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Peer-Reviewed Journal of the Academy of General Dentistry
GENERAL
DENTISTRY
May/June 2015 ~ Volume 63 Number 3
DENTAL MATERIALS n EXODONTIA
COMPUTER DESIGNED/FABRICATED CROWNS
NUTRITION n ROOT CARIES & TREATMENT
ORTHODONTICS n WWW.AGD.ORG
Contents
Departments
8Editorial The peanut butter and
jelly sandwich test
10 To the Editor Discover and defend
the middle ground
12 Pediatrics The pros and cons
of third molar extractions
Cover image adapted from: Nanoleakage
of fiber posts luted with different
adhesive strategies and the effect of
chlorhexidine on the interface of dentin
and self-adhesive cements, on p. 31
78 Oral Diagnosis Apical lesion of
mandibular bicuspid and Apical
lesion of maxillary molar
79 Answers Oral Diagnosis;
Self-Instruction exercises No. 349,
350, 351; and Erratum.
14 Restorative Dentistry Specialist
relationships in interdisciplinary
dentistry
Clinical articles
Continuing Dental
Education (CDE)
Opportunities
Earn 2 hours of CDE
credit by signing up
for and completing the
SELF-INSTRUCTION exercises
based on various subjects.
17 Exodontia A retrospective study
on the use of a dental dressing
to reduce dry socket incidence
in smokers
James T. Murph Jr., DMD
Susan H. Jaques, DMD
Alexander N. Knoell, DMD
Geoffrey D. Archibald, DDS
Stan Yang, PhD
Danielson Guedes Pontes, DDS, MS
Cintia Tereza Pimenta Araujo, DDS, MS
Lucia Trazzi Prieto, DDS, MS
Dayane Carvalho Ramos Salles de Oliveira, DDS, MS
Erick Kamiya Coppini, DDS, MS
Carlos Tadeu Santos Dias, DDS, MS, PhD
Luis Alexandre Maffei Sartini Paulillo, DDS, MS, PhD
38 Self-Instruction Exercise No. 367
26 Orthodontics Kinetics of salivary
pH after acidic beverage intake by
patients undergoing orthodontic
treatment
Please visit www.agd.org/
gdindex to peruse
our Index of Articles.
Arranged by topic,
this index provides a
comprehensive list of
articles published on a
particular topic in past
issues and includes
PubMed citation
information.
31 Dental Materials Nanoleakage
of fiber posts luted with different
adhesive strategies and the effect
of chlorhexidine on the interface of
dentin and self-adhesive cements
22 Nutrition What every dentist
should know about artificial
sweeteners and their effects
Zachary Aaron Starr
Judith A. Porter, DDS, EdD, FICD
Nasir Bashirelahi, PhD
General Dentistry
Index of Articles
available online.
SELF -INSTRUCTION
Cecilia P. Turssi, DDS, MS, PhD
Carolina S. Silva, DDS
Enrico C. Bridi, DDS
Flavia L.B. Amaral, DDS, MS, PhD
Fabiana M.G. Franca, DDS, MS, PhD
Roberta T. Basting, DDS, MS, PhD
39 Computer Designed/Fabricated
Crowns Microcomputed
tomography marginal fit evaluation
of computer-aided design/
computer-aided manufacturing
crowns with different methods of
virtual model acquisition
Flavio Domingues das Neves, DDS, MS, PhD
Celio Jesus do Prado, DDS, MS, PhD
Marcel Santana Prudente, DDS, MS
Thiago Almeida Prado Naves Carneiro, DDS, MS
Karla Zancope, DDS, MS
Leticia Resende Davi, DDS, MS, PhD
Gustavo Mendonca, DDS, MS, PhD
Lyndon Cooper, DDS, MS, PhD
Carlos Jose Soares, DDS, MS, PhD
www.agd.org
General Dentistry
May/June 2015
1
43 Dental Materials The effect of
using propylene glycol as a vehicle
on the microhardness of mineral
trioxide aggregate
Amin Salem Milani, DDS, MSc
Alireza Banifatemeh, DDS
Saeed Rahimi, DDS, MSc
Mohammad Asghari Jafarabadi, PhD
47 Tooth Whitening/Bleaching
Clinical performance of
topical sodium fluoride when
supplementing carbamide peroxide
at-home bleaching gel
Daphne Camara Barcellos, DDS, MS, PhD
Graziela Ribeiro Batista, DDS, MS, PhD
Melissa Aline da Silva, DDS, MS
Patricia Rondon Pleffken, DDS, MS, PhD
Marcia Carneiro Valera DDS, MS, PhD
SELF -INSTRUCTION
51 Dental Materials Physical
properties of a new sonically placed
composite resin restorative material
Emily T. Ibarra, DMD, MS
Wen Lien, DDS, MS
Jeffery Casey, DDS
Sara A. Dixon, DDS, MS
Kraig S. Vandewalle, DDS, MS
57 Self-Instruction Exercise No. 368
58 Cracked Tooth & Restorations
Fracture resistance of weakened
roots restored with different
intracanal retainers
Juliana Broch, MSD
Ana Maria Estivalete Marchionatti, DDS, MSD
Cesar Dalmolin Bergoli, MSD, PhD
Luiz Felipe Valandro, MSD, PhD
Osvaldo Bazzan Kaizer, MSD, PhD
Instructions for
Authors
For information on
submitting a manuscript
for publication in General
Dentistry, please visit
www.agd.org/gdauthorinfo.
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64 Dentistry for the Medically
Compromised Dental management
of a patient with Wilson’s disease
Paulo Sergio da Silva Santos, DDS, MsC, PhD
Karin Sa Fernandes, DDS, MsC, PhD
Alexandre Fraige, DDS, PhD
Marina Gallottini, DDS, MsC, PhD
67 Root Caries & Treatment
Endodontic treatment of mandibular
molars with atypical root canal
anatomy: reports of 4 cases
Raju Chauhan, BDS, MDS
Shweta Singh, BDS, MDS
SELF -INSTRUCTION
71 Practice Management &
Human Relations Hearing loss
associated with long-term exposure
to high-speed dental handpieces
Sarah M. Theodoroff, PhD
Robert L. Folmer, PhD
77 Self-Instruction Exercise No. 369
e1 Dental Materials Evaluation of
the bond strengths of 3 endodontic
cements via push-out test
Nadia de Souza Ferreira, PhD
Raffaela Di Iorio Jeronymo Ferreira, PhD
Patricia Campos Ferreira da Rosa, MS
Ana Paula Martins Gomes, PhD
Carlos Henrique Ribeiro Camargo, PhD
Claudio Antonio Talge Carvalho, PhD
Marcia Carneiro Valera, PhD
e4 Exodontia Management of
uncommon complications in
seemingly routine oral surgeries
Shayan Salim, BS
Andrew Newman, BS
James J. Closmann, DDS
Thomas J. Borris, DDS
Approved PACE Program Provider FAGD/MAGD credit.
Approval does not imply acceptance by a state or
provincial board of dentistry or AGD endorsement.
08/01/2014 to 07/31/2016. Provider ID# 108066
www.agd.org
General Dentistry
May/June 2015
3
Advisory Board
For Advisory Board members’
biographies, visit www.agd.org/
gdadvisoryboard.
Dental Materials
Howard S. Glazer, DDS, FAGD
Dental Public Health
Larry Williams, DDS, ABGD, MAGD
Esthetic Dentistry
Wynn H. Okuda, DMD
Endodontics
Gerald N. Glickman, MS, DDS,
MBA, JD
Geriatric Dentistry
Eric Zane Shapira, DDS, MAGD,
MA, MHAv
Implantology
Wesley Blakeslee, DMD, FAGD
Oral and Maxillofacial
Pathology
John Svirsky, DDS, MEd
Oral and Maxillofacial
Radiology
Dale A. Miles, BA, DDS, MS,
FRCD(C)
e11 Case Presentations Unusual cases
of transmigrated mandibular canines
Lata Goyal, MDS
e16 Pediatric Dentistry Clinical
outcomes of indirect composite
restorations for grossly
mutilated primary molars:
a clinical observation
Neeti Mittal, BDS, MDS
Binita Srivastava, BDS, MDS
e22 Diagnosis of Oral Pathology
Clinicopathological aspects of
25 cases of sialolithiasis of minor
salivary glands
e32 Prosthodontics/Removable
Use of a bite registration vinyl
polysiloxane material to identify
denture flange overextension and/
or excessive border thickness in
removable prosthodontics
C. Brent Haeberle, DMD
Amara Abreu, DDS, MSD
Kurt Metzler, DDS, MS
e36 Dental Materials Low-shrinkage
composites: an in vitro evaluation of
sealing ability after occlusal loading
Marco Tullio Brazao-Silva, DDS, PhD
Fabio Cesar Prosdocimi, DDS, PhD
Celso Augusto Lemos-Junior, DDS, PhD
Suzana Cantanhede Orsini Machado de Sousa,
DDS, PhD
Marcos O. Barceleiro, DDS, MSD, PhD
Giulia Marins Soares, DDS
Olivia Espindola, DDS
Sergio Kahn, DDS, MSD, PhD
Isis Andrea Venturini Pola Poiate, DDS, MSD, PhD
Helio Rodrigues Sampaio Filho, DDS, MSD, PhD
e27 Medical Health History/
Factors Oral manifestations in
gastroesophageal reflux disease
Preetha A., MDS
Sujatha D., MDS
Bharathi A. Patil, MDS
Sushmini Hegde, MDS
Oral and Maxillofacial Surgery
Karl Koerner, DDS, FAGD
Orthodontics
Yosh Jefferson, DMD, FAGD
Pain Management
Henry A. Gremillion, DDS, MAGD
Pediatrics
Jane Soxman, DDS
Periodontics
Samuel B. Low, DDS, MS, MEd
Pharmacology
Thomas Viola, RPh, CCP
Practice Management
Mert N. Aksu, DDS, JD, MHSA, FAGD
Coming next issue
Prosthodontics
In the July/August issue of General Dentistry
Joseph Massad, DDS
Jack Piermatti, DMD
4
May/June 2015
• Maxillary sinus and success of dental implants: an update
• Remineralizing agents: effects on acid-softened enamel
• Influence of irrigation protocols on the bond strength of
fiber posts cemented with a self-adhesive luting agent 24
hours after endodontic treatment
• Detection of Class II caries on the iPad retina display
General Dentistry
www.agd.org
In the May issue of
AGD Impact
• The Dangers of
E-Cigarettes, Water Pipes,
and Smokeless Tobacco
• AGD 2015 Meeting
Preview
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Editor
Roger D. Winland, DDS, MS, MAGD
Associate Editor
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Director, Communications
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General Dentistry
May/June 2015
7
Editorial
The peanut butter and jelly sandwich test
G
ood communication always
includes an effective transfer
of knowledge. As the Chicago
Sun-Times columnist Sydney J.
Harris once pointed out, communication is not about giving out, but
getting through.
Insightful teachers understand the
distinction between giving out and
getting through.
When my daughter Anica was in
the fourth grade, she came home
from school one day and described
how her teacher, Mrs. De Leon, demonstrated to the class the
importance of clear communication. Mrs. De Leon started by
giving a lesson on writing clearly. Then she asked each pupil to
take out a sheet of paper and pencil and write a set of instructions. “Tell me exactly how to make a peanut butter and jelly
sandwich,” she said.
Mrs. De Leon collected the work. “Now we’ll see how well
I can follow your directions,” she announced. She shuffled the
papers and placed them neatly in a stack on her desk. Next, to
the students’ amazement, she opened a drawer and pulled out in
quick succession a loaf of bread, a jar of peanut butter, a squeeze
bottle of grape jelly, a knife, and a roll of paper towels, all of
which she arranged on the desktop next to the papers. Mrs. De
Leon called each child, one by one, up to her desk. Reading aloud
the student’s own instructions, she made each child a sandwich.
The children discovered, personally and graphically, how easily
fragmented phrases and lapses in logic create confusion. One fourth
grader got only a smear of peanut butter on her bread, and one just
got jelly. One kid collected two pieces of bread alone. Another, to
the gleeful howls of his classmates, had peanut butter spread across
the palm of his hand. (“You put on the peanut butter,” the boy had
written. “Put it on what?” Mrs. De Leon asked with a smile as she
grasped his wrist.) Out of nineteen students, only three went back
to their desks holding a complete sandwich of peanut butter and
jelly correctly layered between two slices of bread.
8
May/June 2015
General Dentistry
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Dental patients aren’t so different from those fourth graders.
What do our patients really know about what we try to teach
them? If we gave people a test, asking them to explain back to us
what they understand about their treatment, how many would
get only the peanut butter, or a lonely crust?
Mrs. De Leon’s demonstration suggests four lessons in communications for dentists. First, establish common ground. Don’t
make too many assumptions about what people really grasp. For
instance, my daughter Jillian used to take for granted that her
friends all knew her dad is a dentist. When she was in the eighth
grade, Jillian arrived at softball practice on a hot summer afternoon with gauze in her mouth. “My dad just pulled three of my
teeth,” she explained. There was silence in the dugout. Then one
of her teammates said, quietly, “When I get in trouble, my dad
only puts me in time-out.”
Second, practice precise communication. Explain procedures
slowly, and several times. Articulate each step: “Now I’m putting
a ring around the tooth to keep the edge of the resin smooth and
well formed.” Offer written handouts.
Third, administer a peanut butter and jelly sandwich test. Ask
for feedback. See how much you can understand of what your
patients explain about their own treatment. I am still surprised
at how many people who have three or four crowns in their
mouth don’t know what one is.
Fourth, write more than you think you need to in patient
charts. Describe procedures precisely so others can understand.
Update medical histories, chart existing restorations, and label
radiographs. Don’t forget to record clear diagnoses and visible
treatment plans. You never know when you’ll have to undergo
the peanut butter and jelly sandwich test yourself.
Eric K. Curtis, DDS, MA, MAGD
Associate Editor
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To the Editor
Discover and defend the middle ground
I
found the March/April 2015 Ethics column, Case No. 11: Dear
John, to be both enlightening and troubling. I dutifully followed
the trail of bread crumbs to the destination chosen by the author:
“the [doctor’s] professional ethics appear questionable in this case.”
While a disclaimer was included that all of the information for this
case study was provided from a letter reflecting a one-sided conversation, the overall tone of the article felt narrow and foreordained.
If ethics can be defined as a way of systematizing, exploring, and
discussing concepts of right and wrong conduct, ethical discussions
feel incomplete if only the rightness or wrongness of an isolated
decision or action is reported. Perhaps a more effective way to teach
ethics might be to accurately describe contrast and allow readers
to discover and defend their middle ground. While such a method
would require an adjustment to how case studies generally are
presented, attacks with “should” and “ought to” frequently paralyze
openness to change and activate defense mechanisms.
Exposing that sentiment, I heartily applaud the idea that a
general dentist is a valuable asset in the overall care of all patients.
I further agree that the specialized care offered by general dentists
might have positively impacted the outcomes described in the
case reported. I echo concern that the introduction to the patient
of the idea that he needed care from an additional specialist may
have created a barrier to building trust with a general dentist, and
may have confused the patient about where to go to next on his
journey toward ideal health.
I do not feel the facts presented in this case study support the
consideration of a refund for services rendered, although, should
the assumptions made in the report prove to be factual, it is not
unreasonable for the dentist to consider.
The self-referral of patients to specialists is a long-standing
dilemma in health care. In medicine, more gateways seem to have
been erected between primary care specialists and secondary or
tertiary care specialists. Perhaps patients could be better assisted in
receiving excellent comprehensive care in oral health if the dental
profession considers and implements similar safeguards.
I thank the author for her treatment of such a thought-provoking topic.
David A. Keller, DDS, MBA, MAGD, ABGD, FACD
Vancouver, Washington
Response from Dr. Roucka
Thank you for your letter. Your points are well taken. The onesidedness of the letter in this case is an element that I hoped
would be thought provoking. The fact that we are having this
dialogue leads me to believe I was successful in that regard.
A monetary refund for care or bad outcomes is a topic that
frequently touches a nerve in conversation among health care
providers. The fear that the issuing of a refund in such circumstances will be perceived as an admission of guilt is not
unfounded or unprecedented. In some cases, however, refunds or
account credits may be appropriate.
The major points I hoped to highlight in this dilemma are the
dentist’s obligation to provide informed consent and practice
within the standard of care as well as the dentist’s and patient’s
duty to optimize the treatment outcome. When a patient selfrefers to a specialist, treatment cannot be performed in a vacuum.
The patient cannot be expected to know the implications of
the lack of comprehensive care or noncompliance unless it is
explained explicitly in language he/she understands. This responsibility ultimately falls on the dentist.
Hearing only one side of the story in this case complicates the
matter, but the clues to the ultimate conclusion that was proposed
are the following:
1. The language used in the letter was not appropriate
for most lay people. There was a lot of dental jargon. If
“informed consent” was obtained using the same level
of jargon, then John probably did not fully understand
what was being explained to him regarding the root
canal itself, the long-term prognosis of the tooth, and
the implications of not treating his periodontal disease.
Admittedly, this is an assumption in this case based solely
on the letter.
2. Should Dr. Huper have performed a root canal to completion for a patient with obvious periodontal disease and no
general dentist? Dr. Huper had other options to relieve
John’s pain. Perhaps a pulpectomy would have been more
appropriate until a full treatment plan was developed.
3. The referral of John to a periodontist instead of a general
dentist is also problematic in my opinion. John was
in need of comprehensive care first and foremost, not
immediate referral to another specialist. Perhaps if he had
received comprehensive care, there would be no case to
discuss here. Again, this is another assumption based on
the contents of the letter.
If Dr. Huper had made the referral to a general dentist, had
written the letter in language an average patient could understand, and performed emergency treatment only on tooth No. 2,
and the outcome were the same, the conclusion of this case would
have been much different from my perspective. He would have
practiced within the standard of care.
Once again, I thank you for your thoughtful letter. Ethics is
never black and white but occasionally, especially when it comes
to important issues like informed consent and the standard of
care, it is more black and white than gray.
P.S. I enjoyed your “trail of bread crumbs” analogy. Well put!
General Dentistry welcomes correspondence from its readers. You can send letters to General Dentistry Editor, AGD, 560 W. Lake St., 6th Floor, Chicago, IL 60661-6600,
or email us at [email protected]. The editors reserve the right to edit all submissions. We cannot print letters that have been submitted to other publications.
10
May/June 2015
General Dentistry
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Pediatrics
The pros and cons of third molar extractions
Jane A. Soxman, DDS
T
he decision to recommend the extraction of third molars
for teenaged patients requires consideration of the ramifications of the procedure. Before extraction is discussed for a
particular patient, a panoramic radiograph should be obtained to
determine the presence or congenital absence of third molars. In
a study of American adolescents, 15% of the sample were missing at least 1 third molar, and 2% were congenitally missing all 4
third molars.1 Only 3/4 of patients have all 4 third molars.2 Tooth
bud formation occurs at about 4-5 years of age, initial mineralization at 7-10 years, end crown mineralization at 12-15 years,
and eruption at 17-21 years; root formation is completed at
18-25 years of age.3 The third molar may not be visualized radiographically until a child is about 10 years of age.
Pros
Extraction is typically recommended at ages 15-16 years or
when tooth formation has progressed to a furcation. The risk of
alveolar nerve damage is reduced if root formation is minimal.
If the maxillary third molar is close to the floor of the sinus,
extraction may be delayed, however, to avoid inadvertent perforation of the floor of the sinus and/or displacement of the tooth
into the sinus.
In younger patients, the overlying bone may lift away with a
curette, resulting in more rapid healing and reduced postoperative
morbidity and pain because there is less surgical trauma. When
postoperative outcomes were compared with the surgical difficulty, patients older than 21 years experienced prolonged recovery
for lifestyle and oral function along with pain that lasted for
almost 2 days longer than that experienced by younger patients.2
White & Proffit reported an association between the periodontal pathologies of third molars that affects adjacent, permanent
second molars along with increased chances of pericoronitis and
symptomatic periodontal inflammatory disease in an environment conducive to anaerobic bacteria.2 With partial eruption of
an impacted mandibular third molar, food may become trapped
under the operculum, or the opposing molar may injure the gingival tissue, resulting in pericoronitis. In a study by Garaas et al,
55% of subjects (average age of 25 years) had probing depths of
4 mm or more on the distal surfaces of the third molars.3
Impacted mandibular third molars may result in attachment
loss and periodontal defects on the distal surfaces of the mandibular second molar. Faria et al found that, prior to extraction,
the average probing depth distal to the mandibular second
molar was 5.70 mm. Twelve months after surgery, the probing
depth was 3.77 mm.4
The distal surface of the second molar is difficult to floss,
promoting caries and gingival inflammation. Jung & Cho found
partially impacted mesioangular third molars resulted in a high
incidence of both caries and periodontal bone loss affecting the
adjacent second molar.5 Moreover, maxillary third molars often
12
May/June 2015
General Dentistry
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erupt with a buccal inclination, resulting in pain and inflammation caused by the trapping of the buccal mucosa between the
maxillary and mandibular molars.
Histopathological studies have shown the presence of cystic
changes in up to 50% of patients older than 20 years of age.6 In
addition, early extraction avoids complications that may occur in
patients with later health risk factors, such as history of bisphosphonate use, sexually transmitted diseases, chemotherapy, cardiac
disease with valve replacements, hypertension, diabetes, or smoking, as well as complications associated with deeper impactions.7
Dry socket, or alveolar osteitis, occurs 3 times more frequently in
females taking oral contraceptives.8 The presence of unerupted
third molars creates a 2.5 times greater chance of an angle fracture
of the mandible after a traumatic injury to the face.9
The staggering cost of odontogenic infection is also cited as a
reason for prophylactic removal of third molars. Fifty-five percent
of odontogenic infections requiring hospitalization were caused
by third molars. In a 2012 study, overall hospital costs were
$749,382 with an average of $17,842 per person.10
Cons
Stathopoulos et al found only 2.77% pathology in impacted
third molars and concluded that extraction of asymptomatic
third molars may not be justified.11 Kandasamy also reported
that it is rare to find the development of cysts and tumors around
impacted third molars and that removal may increase probing
depth distal to the second molar.12
Avoidance of mandibular incisor crowding is often a reason
stated for prophylactic removal of third molars. However, studies
have shown there is no proof of a causal relationship between
third molars and lower incisor crowding.13,14
During extraction procedures, muscles and ligaments are
stretched, and considerable force to the mandible may occur.
The temporomandibular joint may be traumatized if the patient’s
mouth is opened beyond the normal range of motion for an
extended period of time. Huang & Rue found a 60% increased
risk of temporomandibular disorder after third molar extraction
in adolescents and young adults.15
Complications associated with the risks of anesthesia due to loss
of protective airway reflexes and adverse reactions to drugs must
be considered as well.
Reaching a verdict
The space between the second molar and the ramus has been
cited as the main etiologic factor determining the possibility for
impaction. Extraction of premolars for orthodontic treatment
may be deemed beneficial for the eruption of mandibular third
molars. However, this theory has not proven to be the case.
Although adequate retromolar space may be present, it is the
inclination of the third molar that determines impaction.
Third molars may become upright during formation and eruption; overdiagnosis of impaction should be avoided. The roots
of the mandibular third molars are not fully formed until 18-21
years of age. Once roots are developed, diagnosis of impaction
is fairly reliable. To determine impending impaction, one line is
drawn through the long axis of the third molar and another line
is drawn tangent to the border of the corpus of the mandible. If
the angle between the long axis of the mandibular third molar
and the border of the mandible is <60 degrees, there is a strong
possibility of impaction.16
The recommendation to extract third molars should be made
after all parameters are considered. The clinician must be prepared to justify such a recommendation with evidence-based
guidelines. If the patient was asymptomatic prior to elective
extraction, the possibility of legal action is increased should perioperative or postoperative complications arise. Collaboration with
other treating dentists, such as the orthodontist or oral surgeon,
is mandatory. Once all of the pros and cons are discussed and
acknowledged, the decision to periodically observe or to proceed
with timely extraction can be made with the best interests of the
patient in mind.
Author information
Dr. Soxman is a general practice residency seminar instructor, a
national speaker for continuing dental education, and a diplomate of the American Board of Pediatric Dentistry. She maintains
a private practice in Allison Park, Pennsylvania.
References
1. Nuvvula S, Kiranmayi M, Shilpa G, Nirmala SV. Hypohyperdontia: a genesis of three
third molars and mandibular centrals associated with midline supernumerary tooth in
mandible. Contemp Clin Dent. 2010;1(3):136-141.
2. White RP Jr, Proffit WR. Evaluation and management of asymptomatic third molars:
Lack of symptoms does not equate to lack of pathology. Am J Orthod Dentofacial Orthop. 2011;140(1):10-16.
3. Garaas RN, Fisher EL, Wilson GH, et al. Prevalence of third molars with caries experience
or periodontal pathology in young adults. J Oral Maxillofac Surg. 2012;70(3):507-513.
4. Faria AI, Gallas-Torreira M, Lopez-Raton M. Mandibular second molar periodontal
healing after impacted third molar extraction in young adults. J Oral Maxillofac Surg.
2012;70(12):2732-2741.
5. Jung YH, Cho BH. Prevalence of missing and impacted third molars in adults aged 25
years and above. Imaging Sci Dent. 2013;43(4):219-225.
6. Popescu MA, Popoviciu O. The third molar—a dentistry topic requiring an interdisciplinary approach. Proc Rom Acad B. 2008;3:175-178.
7. American Association of Oral and Maxillofacial Surgeons (AAOMS). White paper. Evidence based third molar surgery. Available at: http://www.aaoms.org/docs/evidence_
based_third_molar_surgery.pdf. Accessed March 3, 2015.
8. Noroozi AR, Philbert RF. Modern concepts in understanding and management of the
“dry socket” syndrome: comprehensive review of the literature. Oral Surg Oral Med
Oral Pathol Oral Radiol Endod. 2009;107(1):30-35.
9. Subhashraj K. A study of the impact of mandibular third molars on angle fractures.
J Oral Maxillofac Surg. 2009;67(5):968-972.
10. Jundt JS, Gutta R. Characteristics and cost impact of severe odontogenic infections.
Oral Surg Oral Med Oral Pathol Oral Radiol. 2012;114(5):558-566.
11. Stathopoulos P, Mezitis M, Kappatos C, Titsinides S, Stylogianni E. Cysts and tumors
associated with impacted third molars: is prophylactic removal justified? J Oral Maxillofac Surg. 2011;69(2):405-408.
12. Kandasamy S. Evaluation and management of asymptomatic third molars: watchful
monitoring is a low-risk alternative to extraction. Am J Orthod Dentofac Orthop. 2011;
140(1):11-17.
13. Zawawi KH, Melis M. The role of mandibular third molars on lower anterior teeth
crowding and relapse after orthodontic treatment: a systematic review. ScientificWorldJournal. 2014;2014:615429.
14. Ades AG, Joondeph DR, Little RM, Chapko MK. A long-term study of the relationship
of third molars to changes in the mandibular dental arch. Am J Orthod Dentofacial Orthop. 1990;97(4):323-335.
15. Huang GJ, Rue TC. Third-molar extraction as a risk factor for temporomandibular disorder. J Am Dent Assoc. 2006;137(11):1547-1554.
16. Turkoz C, Ulusoy C. Effect of premolar extraction on mandibular third molar impaction
in young adults. Angle Orthod. 2013;83(4):572-577.
There is a clinical article on
PEDIATRIC DENTISTRY
in the online edition.
Clinical outcomes of indirect
composite restorations for
grossly mutilated primary molars:
a clinical observation
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General Dentistry
May/June 2015
13
Restorative Dentistry
Specialist relationships in interdisciplinary dentistry
R.A. Solow, DDS
E
arly in my career, my goal in referring patients to specialists
was for the patient to accept the reality that their problems
required treatment involving another office and increased
cost. Sometimes patients resisted these referrals as I had built good
relationships with them and they didn’t want to see another practitioner. I believed that I was explaining their conditions clearly and
referring when they needed diagnostic or definitive care beyond
my ability. I relied on these specialists to make treatment-planning
decisions as they had residency training, confidence, and experience
that I did not. I was impressed by their examination protocols and
their judgments of which procedures would be appropriate and
predictable. I used their referral slips to jot down names and treatment categories. Occasionally, patients would return to me a little
confused as the specialist had mentioned new considerations for
treatment that I hadn’t discussed. I referred many patients to specialists, but only a few new patient referrals were sent to me (Fig. 1).
After 37 years of private practice and decades of continuing
education, my concept of interdisciplinary dentistry has changed
significantly. My practice—restorative dentistry in a fee-for-service
setting—is focused on my interests and what I do best, and also
allows me to spend extra time with patients. My current relationships with specialists mirror the changes I’ve made in my office. As
a general dentist who limits his practice to restorative procedures,
I make more referrals to specialists. I also have to demonstrate to
these specialists why they should refer comprehensive-care patients
to me and why my plan is indicated and predictable. Currently,
approximately half of my new patients come from specialists, and
many of these specialists are also my patients (Fig. 2).
Today, my goal when referring patients to a specialist is to
ensure that they accept optimal care for long-term success. My
responsibility is to diagnose and educate patients so that they
know what the best treatment is and why that is preferable to any
alternative plan. This approach benefits the specialists as they have
highly informed patients who are oriented to the positive results
provided by specialty care.1 I can then refine treatment plans with
my specialist consults, coordinate all care, and solve occlusal and
restorative problems for comfort, esthetics, and stability.
Once I understand who they are, I share my professional evolution and my philosophy of patient care. I show them PowerPoint
presentations, videos, mounted diagnostic casts, preparation dies,
and provisional restorations of my completed interdisciplinary
cases so they can see how I practice. Patient care in my office
is based on thorough examination and education followed by
appropriate, conservative dentistry designed for long-term success. Using these interdisciplinary cases, I discuss each aspect of
the 4 part examination with the specialist: preclinical interview,
clinical examination, imaging, and occlusal analysis.
My relationships with new patients start with 90-minute
comprehensive examinations; they don’t first enter my practice
via hygiene or emergency visits. My consistent experience is that
patients have a very positive initial visit when there is enough
time to examine and explain every problem, when they visualize
their dental status, and when they learn how to predictably avoid
future breakdown. Most patients comment on how unique this
visit is and ask why their previous dentists did not allocate this
time. My goals for the comprehensive examination are to gain a
thorough understanding of the patient’s problem—as determined
by both me and the patient—to foster in the patient an appreciation of my time and knowledge, and to create a complete record
from which to develop a treatment plan for long-term stability
with only routine maintenance.
The preclinical interview—the most important phase of the
examination—is focused on learning who the patient is. This
helps me communicate precisely what new patients need to
know about future treatment decisions. It is critical to schedule
enough time for patients to tell their stories and for them to
know that they have been heard. Patients with extensive medical
and/or dental histories or highly emotional personalities require
Specialist
Specialist
Restorative dentist
Restorative dentist
The specialist’s introduction to my office
All of my specialists have visited my office so that they have an
in-depth understanding of my practice philosophy, technical dentistry, and treatment-planning protocol. I invite new specialists to
my office for individual 2-hour meetings during which they have
my undivided attention, similar to the setting of my new patient
examinations. Over a casual lunch, the conversation starts with
who they are, what influenced them to go into specialty practices,
where they trained, how they like to practice, and what their ideas
of the best generalist/specialist relationships are. I ask them about
their practice philosophies, techniques and technologies used, and
changes that they have made in their practices.
14
May/June 2015
General Dentistry
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Fig. 1. The author’s early-career
specialist-referral pattern.
Fig. 2. The author’s current referral
pattern with enhanced specialist
relationships.
this time. Conversely, patients who prefer a direct and concise
approach need to have the examination proceed in a tightly organized way so that their time is respected. The dentist needs time
to assess patients and to determine if their requests or limitations
are appropriate for the office.
I conduct my clinical examination process in a co-diagnosis
fashion in which I explain the significance of what we are seeing
as the patient observes in a mirror. By asking questions and
maintaining a dialogue, my objective is to involve patients so
that they visualize and understand what is inside their mouths.
I use these comprehensive treatment cases to show how each
part of a clinical examination relates to the final result. The
importance of occlusal analysis with diagnostic casts mounted
in centric relation and computerized occlusal analysis is emphasized. I use photographs, radiographs, computed tomography,
and magnetic resonance imaging in my diagnoses to convey how
restoration is based on the global diagnosis.
Also, at the end of the examination, I educate patients
about the details of oral hygiene so they can prevent recurrent
problems. It is rare that patients attend to homecare properly.
Educating patients on the details of homecare has a profound
effect on how they value me and how they take care of themselves over the long term. Specialists need to know how I
approach each aspect of patient care so that they can practice
congruently. They need to have the same attention to detail and
priority of education so that our patients understand optimal
dentistry and request appropriate treatment.
My visit to the specialist’s office
My best learning experiences have involved spending time in my
specialists’ offices. Initially, these visits were designed to learn who
they were, what they were doing technically, and to assess whether
I might want to specialize in the future. However, I began to recognize the importance of specialists’ interpersonal skills and how
their staffs cared for patients. I began to consider whether my
patients would fit into a particular specialist’s style of practice or if
they would be better suited being seen by a different specialist.
Although continuing education courses and journals have
helped me to understand more of what my specialists see and
do, the conversations in their operatories during procedures have
shown me in 3 dimensions what their concerns and limitations
are for each procedure. These experiences have made me a better
diagnostician and interdisciplinary team member. I can now tell
patients what can be predictably accomplished and what decisions
they should consider with each specialist. I have also gained an
appreciation for the extensive time and effort my specialists expend
during patient care. In some cases, this relationship has progressed
to the point that I treat a patient during the same appointment
(with restorative procedures) after specialist placement of implants,
allowing every detail of the surgery to be discussed.
Case workup and presentation to the specialist
Interdisciplinary care requires communication and coordination
of treatment planning prior to any procedure. Who a patient is
as a person, as well as their concerns, should be the first things
communicated to the specialist. I do this for all cases—whether
a patient needs a single endodontic procedure or a complex
orthodontic-periodontal-restorative treatment plan. A brief statement may contain all the relevant information in the former
case; significantly more may be necessary in the latter. I note
my experience with the patient and my examination data, the
previous dental/endodontic history, and my diagnosis or difficulty in making the diagnosis. Any information that facilitates
the specialist successfully meeting, diagnosing, or treating the
patient is shared.
Roblee defined unidisciplinary therapy as diagnosis, treatment
planning, therapy, and maintenance provided by 1 dentist.2
Its main deficiency is that the full scope of therapy may not be
addressed. Multidisciplinary therapy involves multiple specialists
but without an overall understanding of where various therapies
fit into a comprehensive treatment plan. Interdisciplinary dentofacial therapy is characterized by regimented diagnostic, treatment
planning, and therapeutic procedures with extensive communication between team members. Complex cases typically need
restoration or occlusal equilibration to complete treatment. The
restorative dentist can coordinate and sequence all specialist treatment so that these final steps are predictable for an optimal result.
The following simple checklist facilitates case discussion with
multiple specialists. (1) Create a 1 page list of problems and solutions. Use the data from the 4 part examination detailed above to
list the problems and show how they were defined and verified.
Outline the proposed interdisciplinary treatment plan and why it
is the most appropriate solution for the patient. (2) Specify what
the specialist needs to do for each site to achieve these goals, eg,
“erupt tooth No. 9 2.5 mm incisally and 1 mm facially.” This section would incorporate the results of my model surgery, diagnostic
waxup, or computerized virtual workup. (3) Discuss the appropriateness, predictability, and alternatives to the recommended plan.
Many times, the experience of the specialist can help determine a
predictable and cost-effective procedure from several possible treatments. (4) Determine the sequence and cost of each phase of treatment. Patients need to know the approximate total time and cost of
all aspects of treatment before deciding on their preferred solutions.
In my community, there is an overabundance of highly trained,
ethical, and intelligent specialists. In some communities, specialists are not geographically available and unidiscipinary dentistry is
required to avoid patient nontreatment. Dentists in this situation
need to create relationships with the nearest specialists to learn as
much as they can about their techniques, how these procedures
may change their office routines, and where their limitations
should be. Additionally, dentists in group practice may focus on 1
or 2 specialty procedures and treat patients accordingly.
Specialists have multiple advantages compared to general
dentists practicing in a unidisciplinary style. They have completed residency training with extensive experience in clinical
diagnosis and treatment, and should understand the relationships between their procedures and a comprehensive treatment
plan. Residencies also give a strong scientific foundation for
practice that is based on the dental literature. It is not possible
to stay current in both the general dentistry and multispecialty
literatures. Specialists practice a more narrow scope of procedures, and it is easier to develop expertise in a few compared to
many procedures. They are trained to treat complications that
a general dentist may not frequently encounter, thus improving
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General Dentistry
May/June 2015
15
the overall quality of care. A higher volume of several procedures
creates an economy of scale that makes it economically feasible
to invest in equipment such as surgical microscopes, cone beam
computed tomography, multiple implant systems, or piezoelectric handpieces, improving procedure predictability and quality.
It is difficult to imagine a general dental office that has all the
equipment and materials of an orthodontist, endodontist, periodontist, pedodontist, and oral surgeon.
Dental practice can be a continually positive, evolving professional lifestyle. It may take years of work to develop the scientific
knowledge, technical ability, and people skills needed to find
fulfillment in dentistry.3 Integral to providing patients with
higher quality, durable, and predictable dentistry is recognizing
the complexity of patient problems and developing an appropriate team to treat them. Relationships with specialists who enjoy
teaching and appreciate the synergy of high-quality interdisciplinary care are fundamental to building a better practice.4
Referrals to and from specialists are primarily based on developing personal relationships reflective of core values such as
integrity and lifelong learning.5 The protocols discussed above
will enhance the development of these professional relationships
and improve the quality of patient care.
Author information
Dr. Solow is in private practice in Mill Valley, California, and
a member of the visiting faculty at the Pankey Institute, Key
Biscayne, Florida.
References
1. Krauser JT. Team approach—What do we want from each other? Fla Dent J. 1988;
59(4):40-41.
2. Roblee RD. Interdisciplinary Dentofacial Therapy. A Comprehensive Approach to Optimal Patient Care. Chicago: Quintessence Publishing; 1994.
3. Vered Y, Zakin Y, Ovadia-Gonen O, Mann J, Zini A. Professional burnout: its relevance
and implications for the general dental community. Quintessence Int. 2014;45(1):8790.
4. Kokich VG. Educate your referring dentists. Am J Orthod Dentofacial Orthop. 2013;
143(6):753.
5. Schlieve T, Funderburk J, Flick W, Miloro M, Kolokythas A. How do general dentists and
orthodontists determine where to refer patients requiring oral and maxillofacial surgical procedures? J Oral Maxillofac Surg. 2015;73:509-513.
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General Dentistry
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Exodontia
A retrospective study on the use of a dental
dressing to reduce dry socket incidence in smokers
James T. Murph Jr., DMD n Susan H. Jaques, DMD n Alexander N. Knoell, DMD n Geoffrey D. Archibald, DDS n Stan Yang, PhD
This study assessed the effectiveness of using an oxidized cellulose dental
dressing in order to reduce the rate of alveolar osteitis after posterior
tooth extraction in smokers. Dry socket incidences of heavy smokers from
4 independent dental clinics, which routinely used oxidized cellulose
dental dressings to mitigate dry socket formation between March 2011
and December 2012, were compiled and evaluated. All extraction sites
healed uneventfully except for those cases that developed dry sockets.
Overall, 1.7% of male patients and 2.2% of female patients developed
dry sockets. No conclusive relationship was found between the number
A
dry socket is characterized by the
nonformation or early loss of a
blood clot from a tooth extraction site before the wound has healed.1
Clinically, dry socket formation is
associated with intense pain, a foul smell,
and the disappearance of blood clots
from the socket after tooth extraction.
Causative investigations of dry socket
formation have often been complicated
by the presence of multiple, interrelated
risk factors, including patient age, gender,
smoking status, practitioner’s experience,
effort of extraction, and postextraction
treatment regimen (such as curetting).
Generally, mandibular third molar
extractions have exhibited the highest
dry socket incidence due to the extensive
effort required to extract the entrenched
root structure.1-3
Smoking is known to increase the
risk of dry socket formation. In a study
of mandibular third molar extractions,
smokers were found to be 5 times as
likely to develop dry sockets as nonsmokers.4,5 Studies have shown that the risk of
dry socket formation increased with an
increased daily consumption of cigarettes.
Individuals who smoked on the day of
surgery or Postoperative Day 1 had the
highest incidence of dry sockets.4 In a
review of 1305 extractions among 805
patients performed in a dental training
center, the incidence of dry sockets was
significantly higher among smokers
(12%) versus nonsmokers (4%).6 Tooth
sectioning, smoking, and degree of smoking were found to be associated with the
of cigarettes smoked and dry socket formation among patients in this
study. The results of this study were consistent with the view that gender,
age, postextraction regimen, and multiple extractions affect dry socket
formation. The results indicate that an oxidized cellulose dental dressing
postextraction is a safe and effective method for mitigating dry socket
formation among smokers.
Received: June 30, 2014
Revised: November 13, 2014
Accepted: February 16, 2015
development of alveolar osteitis, with
a significant odds ratio of 4.3, 4.5, and
12.3, respectively.7
Smoking affects blood coagulation,
platelet aggregation, clotting dynamics,
and fibrin structure.8-14 Smokers exhibit a
decrease in oral leukocyte function, are less
responsive to periodontal treatment, and
exhibit reduced bleeding in the extraction
socket.15-17 The suction action of smoking
was hypothesized to affect the formation
of dry sockets by disrupting or dislocating
immature blood clots and by introducing foreign substances into the extraction
site. However, suction using straws did
not cause dry sockets when third molars
were extracted, implying that the effect
of smoking on dry socket formation was
due to a biological cause rather than a
mechanical one.18
Many preventive methods to reduce
the prevalence of dry sockets have been
reported with varying results. These
methods include postextraction irrigation;
the use of antibiotics, analgesics, antiseptic, and antifibrinolytic agents; as well
as the placement of intra-alveolar dressings.19-34 Drugs were either used alone
or soaked into intra-alveolar dressings
to facilitate the application and release
of the agents.26-31 Studies of Gelfoam
(Pfizer, Inc.)—an intra-alveolar dressing—reported a reduction in dry socket
formation in third molar extraction sites
when impregnated with either tetracycline
or lincomycin; however, no reduction was
reported when Gelfoam was used alone
or mixed with aminoacridine.31,32,35-38
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Despite intensive research, the exact cause
of dry socket formation, as well as an
effective treatment to prevent its formation, remains uncertain.19-31,35-38
Oxidized cellulose is a generic term
referring to chemically oxidized cellulose
material, whose properties depend upon
the selection of the cellulosic material and
the chemical oxidation methods employed.
Several oxidized cellulose products have
been approved for clinical use as hemostatic wound dressings to control bleeding.
However, not all oxidized cellulose products exhibit the same characteristics and
performance. BenaCel oxidized cellulose
dental dressing (Unicare Biomedical, Inc.)
was cleared by the FDA for use as a wound
dressing in extraction sites and for the
management of dry sockets.34 The present
retrospective study was initiated after 1
of the original investigators identified a
significant reduction in the dry socket rate
among heavy smokers, who consumed 1
or more packs of cigarettes per day, after
administering the oxidized cellulose dental
dressing postextraction. The hypothesis
was that an effective wound dressing material will aid in controlling bleeding by
stabilizing blood clots, thus reducing the
incidence of dry socket. The objective was
to determine the safety and effectiveness
of oxidized cellulose dental dressings in
reducing dry socket incidence in a routine,
noncontrolled, clinical setting. The dry
socket incidence obtained from this study
was then compared with values reported
in the literature in order to evaluate the
effectiveness of this method.
General Dentistry
May/June 2015
17
Exodontia A retrospective study on the use of a dental dressing to reduce dry socket incidence in smokers
Chart 1. Age distribution of male and female patients.
Chart 2. Percentage of patients based on the
number of packs of cigarettes smoked per day.
30
80
Female
Male
25
60
Percent (%)
Percent (%)
20
15
10
40
30
10
11-20 21-30 31-40 41-50 51-60 61-70 71-80
Age group
Materials and methods
This retrospective study compiled and
analyzed the incidence of dry socket as
recorded by 4 independent practitioners.
These practitioners operated at their own
clinics at separate locations in 3 different
states (Minnesota, Tennessee, and South
Carolina). Between March 2011 and
December 2012, the practitioners routinely
used oxidized regenerated cellulose dental
dressings to control bleeding and mitigate
dry socket formation for high-risk patients,
such as (but not exclusively) those taking
blood thinners and smokers. One practitioner began the use of the dental dressing
early and produced the bulk of the data
during the full length of the study period.
The remaining 3 practitioners did not use
the dressing until the last 8 months of the
study period and produced significantly less
data. To focus on high-risk scenarios with
subsequent higher dry socket incidences, the
data of all smoking patients, whose extractions involved only posterior teeth (the first
premolar to the third molar)—regardless of
the systemic health of the patients and independent of whether they had diseases such
as blood clotting disorders, hypertension, or
diabetes—were included in the study. Each
practitioner used his/her own preferred
extraction and postextraction regimen. All
extractions were traumatic, and no dental
implants were performed immediately or
planned following extraction. The common
link was the use of oxidized regenerated
cellulose dental dressings to alleviate dry
socket formation for all patients.
18
50
20
5
0
Female
Male
70
May/June 2015
General Dentistry
0
0.5
Two forms of BenaCel (plugs, 5 mm
x 7 mm; sheets, 15 mm x 15 mm) were
used by the practitioners. Both forms are
made of the same material and exhibit
the same performance, differing only in
their configurations.34 Generally, sheets
were used in third molar extractions and
plugs were used in all other posterior sites,
depending on the size of the extraction
site and the doctor’s preference. According
to the manufacturer’s product information, the dental dressing material should
dissolve, transforming into a gelatinous
material after contact with blood,
and then be absorbed within 5 days.34
Depending upon the size of the extraction
socket, 1-2 units of dental dressing were
packed into the extraction site. The dental
dressing was inserted into the apex of the
extraction site without suture retention—
unless the site was shallow or a surgical
extraction was performed, in which case
a crisscrossed suture was used to keep the
dressing in the socket. A roll of wet sterile
gauze was placed over the extraction site,
and biting pressure was applied by the
patient until the bleeding stopped.
In general, patients were instructed to
refrain from smoking 1 day before extraction and for at least 1 day postextraction.
Extractions were performed with patients
under local anesthesia. Postextraction,
3 investigators curetted the sockets, while
1 investigator did not curette except
when the site was infected. Patients
were instructed to return for treatment
if bleeding or excessive pain occurred.
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1.0
1.5
2.0
Packs smoked per day
3.0
If a patient returned, a diagnosis of dry
socket was made based on the following criteria: a constant, radiating pain
3-4 days postoperatively, partial or total
absence of a blood clot, and/or tenderness
upon palpation.
Dry socket incidences were analyzed
for the following variables: patient age,
gender, number of packs of cigarettes
smoked per day, and curetting status.
Results
The data of 472 patients (all smokers,
with 707 posterior extractions performed)
were used for this retrospective analysis.
Of these procedures, 519 extractions
(73%) were generated from 1 clinic, while
47 (7%), 64 (9%), and 77 (10%) extractions were collected from the remaining
3 clinics. The number of extractions
reflects the experience and length of time
the practitioners used the dressing during
the study period and the demographic
of the patient population for each clinic.
Patients’ ages ranged from 11 to 86. The
average ages of male and female patients
were 39 and 41 years of age, respectively,
with men being a larger proportion of the
sample (61%). More than 85% of patients
were between 21 and 60 years of age
(Chart 1). Each patient’s smoking status
was categorized by the number of packs
smoked per day. On average, patients
consumed 1.1 ± 0.4 packs of cigarettes
each day, with a range of 0.5 to 3.0 packs
per day. The majority of patients smoked
1 pack of cigarettes per day (Chart 2).
Chart 3. Percentage of extractions based on extraction site.
Chart 4. Dry socket incidence according to age bracket.
30
5.0
4.5
Female
Male
25
3.5
Percent (%)
20
Percent (%)
Female
Male
4.0
15
10
3.0
2.5
2.0
1.5
1.0
5
0.5
0
First
premolar
Second
premolar
First
molar
Second
molar
Third
molar
0
<20
21-30
31-40 41-50
Age group
Number of patients
Number of
dry sockets
Number of
extractions
Percentage of patients
with dry sockets
7.0
Male
287
5
440
1.7
6.0
Female
185
5
267
2.2
5.0
Total
472
10
707
1.9
One patient developed 2 dry sockets from the same visit.
Percent (%)
Group
a
>60
Chart 5. Dry socket incidence
according to the number of packs
of cigarettes smoked per day.
Table 1. Dry socket incidence according to gender.
a
51-60
4.0
3.0
2.0
Second and third molar extractions
constituted about 50% of all extractions
(Chart 3). The remaining extractions
included first molar, first premolar, and
second premolar extraction sites. Overall,
71% of men and 68% of women received
single extractions, and 22% of men and
women received double extractions. The
remaining patients had >2 extractions
during the same visit.
Table 1 lists patient population, number
of extractions, and the percentage of
patients who developed dry sockets in
accordance with the patients’ genders.
A total of 10 dry sockets developed in
9 of 472 patients with 707 extractions.
Four female and five male patients experienced dry sockets postextraction. One
33-year-old woman who smoked 1 pack
of cigarettes per day had 2 dry sockets
after multiple extractions from the same
visit. Overall, 1.7% of men (1.1% of
extractions) and 2.2% of women (1.9% of
extractions) developed dry sockets.
Chart 4 shows the percentage of patients
in each age bracket that developed dry sockets. The 4 women, who developed a total
of 5 dry sockets, were between 33 and 42
years of age; of these women, 2 each were
between 33 and 40 (4.7%) and between 41
and 42 (4.4%) years of age. Five dry sockets
occurred in 5 men who were between 27
and 54 years of age; of these men, 2 each
were between the ages of 41 and 50 (3.0%)
and between 51 and 60 (5.1%). One man
between the ages of 21 and 30 (1.25%)
also developed a dry socket.
Chart 5 depicts the prevalence of dry
sockets versus the number of packs of
cigarettes smoked by patients per day. The
dry socket prevalence ranged from 1.4%
for 1 pack per day smokers to 6.3% for 1.5
packs per day smokers. The prevalences of
dry sockets were 1.6% and 1.5%, respectively, for men and women who had single
extractions, and 2.2% and 3.8%, respectively, for men and women who underwent
2 or more extractions during the same visit.
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1.0
0
0.5 1.0 1.5 2.0 3.0
Packs smoked per day
The number of extractions performed by
each practitioner and the practitioner’s
postextraction regimen (curetting or noncuretting) along with the respective dry
socket prevalences are listed in Table 2.
Discussion
This work is one of the earliest studies of
the use of oxidized cellulose dental dressings
to prevent dry socket formation in smokers. Although oxidized cellulose products
such as Surgicel (Johnson & Johnson) have
widely been used as hemostatic agents to
control bleeding postextraction, there have
been very few studies on the effectiveness
of oxidized cellulose as a wound dressing to
prevent or manage dry socket formation.33
General Dentistry
May/June 2015
19
Exodontia A retrospective study on the use of a dental dressing to reduce dry socket incidence in smokers
Table 2. Curetting, extraction, and dry sockets statistics per practitioner in study.
Practitioner ID
Curetting
0.8
Yes
77
1
1.3
Yes
64
2
3.1
47
3
6.4
707
10
1.4
2
3
4
Yes
-
Suleiman reported that the use of an
oxidized cellulose dressing increased dry
socket incidence.30 In contrast, the dressing
used in the present study was found to be
biocompatible and noninterfering with
wound healing. The administration of
the oxidized cellulose dental dressing was
reported to be easy and nonintrusive to the
practitioner’s regular routine. All study sites
achieved hemostasis before patients were
discharged from the clinics. Other than the
cases of patients who developed dry sockets, postoperative healing was uneventful.
There were no reported instances of swelling, discomfort, infection, or prolonged
bleeding caused by the use of the dental
dressing. The wound healing characteristics
of oxidized cellulose dressings observed in
this study were similar to the results of a
preliminary retrospective study in which
no postoperative bleeding, infections, or
alveolitis were reported among 150 extractions from 118 patients, including both
smokers and nonsmokers.39
Dry socket incidence rates among
smokers have been reported to range
from 6.4% to 40.0% in mandibular
third molar extractions and from 3.4%
to 12.0% in general extractions, respectively.6,17,19,21,27,38,40 Dry socket incidence
increases with increasing degrees of smoking, and patients who smoke immediately
before or after tooth extraction have the
highest incidence of dry socket formation.4
In the present study, approximately 90%
of smokers smoked an average of 1 pack
per day or more; these patients were considered “heavy” smokers. Despite emphatic
instructions to refrain from smoking, the
degree of patient compliance with these
instructions could not be ascertained. It
could be supposed that not all patients
complied with the instructions, as some
May/June 2015
Percentage of dry sockets
4
No
Total
20
Number of dry sockets
519
1
General Dentistry
Number of extractions
patients were observed smoking immediately after walking out of the clinics. Even
so, the overall dry socket incidence rate for
posterior extractions in smoking patients
was 1.9%. Compared with the reported
data in the literature, the relatively low
incidence of dry sockets in this study
support the hypothesis that oxidized cellulose dental dressings reduce dry socket
incidence among smokers.
Female patients showed a slightly higher
prevalence of dry sockets compared to male
patients (2.2% versus 1.7%). The 4 women
who developed dry sockets ranged in age
between 33 and 42 years. Given the relatively low overall occurrence of dry sockets
in the study, the concentration of dry socket
patients in such a narrow age range was significant and suggested that adult, premenopausal female smokers are at an increased
risk of developing dry sockets. The 5 men
who developed dry sockets ranged in age
from 27 to 54. There appeared to be an
upward trend in dry socket prevalence
among male smokers as age increased, with
the older (51 to 60) age group exhibiting a
higher dry socket prevalence (5.1%) than
other age groups (Chart 4).
There was no trending effect on dry
socket incidence with regard to the
number of packs of cigarettes consumed
per day (Chart 5). However, as approximately 80% of patients smoked 1 pack of
cigarettes per day, it cannot be concluded
that there is any relationship between the
number of packs of cigarettes smoked and
dry socket prevalence.
The practitioner who produced the most
data had the least amount of dry socket
incidence. Thus, the experience of practitioners in extraction appears to affect the
dry socket incidence. However, this factor
is commingled with the postextraction
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curetting regimen, as the most experienced practitioner in this study did not
curette the socket postextraction, while
the remaining 3 practitioners did. Both
male and female patients showed a higher
prevalence of dry socket formation if the
postextraction treatment regimen involved
curetting. In addition, multiple extractions
also resulted in higher percentages of dry
socket formation among both genders.
Conclusion
The findings of this retrospective study are
consistent with those reported in the literature, in that a patient’s gender, age, and
postextraction regimen—along with practitioners’ experience—have been identified
as factors affecting the prevalence of dry
socket formation, even among smoking
patients. While further studies are needed
to substantiate the results derived from
this retrospective study, it can be concluded that the use of the oxidized cellulose dental dressing appears to be safe and
effective in reducing dry socket formation
among smokers. Adult, premenopausal
female smokers and older male smokers emerged as groups who are at higher
risk of developing dry sockets. Multiple
extractions in 1 visit and postextraction
curetting also resulted in higher dry socket
incidences. The overall results appeared to
indicate that the use of oxidized cellulose
is effective in reducing dry socket incidence regardless of the patient’s systemic
health conditions and the practitioner’s
treatment modality.
Author information
Dr. Murph is in private practice in Conway,
South Carolina, Dr. Jaques is in private
practice in Holly Hill, South Carolina,
Dr. Knoell is in private practice in
Henderson, Tennessee, and Dr. Archibald
is in private practice in North Branch,
Minnesota. Dr. Yang works for Unicare
Biomedical, Inc., Laguna Hills, California.
Disclosure
Unicare Biomedical, Inc. manufactures
and sells BenaCel oxidized cellulose dental
dressing, which is largely used in this study.
For their efforts, Unicare Biomedical provided BenaCel at a discounted price to the
doctors to carry out their procedures and
to provide data for this study. In no other
way did Unicare Biomedical, Inc. influence the results or behaviors of the doctors
involved in this study.
References
1. Blum IR. Contemporary views on dry socket (alveolar
osteitis): a clinical appraisal of standardization, aetiopathogenesis and management: a critical review. Int J
Oral Maxillofac Surg. 2002;31(3):309-317.
2. Cardoso CL, Rodrigues MT, Ferreira Junior O, Garlet
GP, de Carvalho PS. Clinical concepts of dry socket.
J Oral Maxillofac Surg. 2010;68(8):1922-1932.
3. Kolokythas A, Olech E, Miloro M. Alveolar osteitis: a
comprehensive review of concepts and controversies.
Int J Dent. 2010;2010:249073.
4. Sweet JB, Butler DP. The relationship of smoking to
localized osteitis. J Oral Surg. 1979;37(10):732-735.
5. Sweet JB, Butler, DP. Predisposing and operative factors: effect on the incidence of localized osteitis in
mandibular third-molar surgery. Oral Surg Oral Med
Oral Pathol. 1978;46(2):206-215.
6. Abu Younis MH, Abu Hantash RO. Dry socket: frequency, clinical picture, and risk factors in a Palestinian
dental teaching center. Open Dent J. 2011;5:7-12.
7. Bortoluzzi MC, Capella DL, Barbieri T, Marchetti S,
Dresch CP, Tirello C. Does smoking increase the incidence of postoperative complications in simple exodontia? Int Dent J. 2012;62(2):106-108.
8. Ambrus JL, Mink IB. Effect of cigarette smoking on
blood coagulation. Clin Pharmacol Ther. 1964;5:428431.
9. Astrup P, Kjeldsen K. Carbon monoxide, smoking, and
atherosclerosis. Med Clin North Am. 1974;58(2):323350.
10. Billimoria JD, Pozner H, Metselaar B, Best FW, James
DC. Effect of cigarette smoking on lipids, lipoproteins,
blood coagulation, fibrinolysis and cellular components of human blood. Atherosclerosis. 1975;21(1):
61-76.
11. Allen RA, Kluft C, Brommer EJ. Effect of chronic smoking
on fibrinolysis. Arteriosclerosis. 1985;5(5):443-450.
12. Hawkins RI. Smoking, platelets and thrombosis. Nature. 1972;236(5348):450-452.
13. Barua RS, Sy F, Srikanth S, et al. Effects of cigarette
smoke exposure on clot dynamics and fibrin structure:
an ex vivo investigation. Arterioscler Thromb Vasc Biol.
2010;30(1):75-79.
14. Moschos CB, Ahmed SS, Lahiri K, Regan TJ. Chronic
smoking in an animal model. Effects on clotting and
fibrinolysis. Atherosclerosis. 1976;23(3):437-442.
15. Eichel B, Shahrik HA. Tobacco smoke toxicity: loss of
human oral leukocyte function and fluid-cell metabolism. Science. 1969;166(3911):1424-1428.
16. Jones JK, Triplett RG. The relationship of cigarette
smoking to impaired intraoral wound healing: a review of evidence and implications for patient care.
J Oral Maxillofac Surg. 1992;50(3):237-239; discussion 239-240.
17. Meechan JG, Macgregor ID, Rogers SN, Hobson RS,
Bate JP, Dennison M. The effect of smoking on immediate post-extraction socket filling with blood and on
the incidence of painful socket. Br J Oral Maxillofac
Surg. 1988;26(5):402-409.
18. Bloomer CR. Straws do not cause dry sockets when
third molars are extracted. Tex Dent J. 2012;129(1):
25-32.
19. Tolstunov L. Influence of immediate post-extraction
socket irrigation on development of alveolar osteitis
after mandibular third molar removal: a prospective
split-mouth study, preliminary report. Br Dent J.
2012;213(12):597-601.
20. Sweet JB, Butler DP, Drager JL. Effects of lavage techniques with third molar surgery. Oral Surg Oral Med
Oral Pathol. 1976;41(2):152-168.
21. Bonine FL. Effect of chlorhexidine rinse on the incidence of dry socket in impacted mandibular third molar extraction sites. Oral Sur Oral Med Oral Pathol Oral
Radiol Endod. 1995;79(2):154-157; discussion 157158.
22. Hall HD, Bildman BS, Hand CD. Prevention of dry socket with local application of tetracycline. J Oral Surg.
1971;29(1):35-37.
23. Sanchis JM, Saez U, Penarrocha M, Gay C. Tetracycline
compound placement to prevent dry socket: a postoperative study of 200 impacted mandibular third molars. J Oral Maxillofac Surg. 2004;62(5):587-591.
24. Reekie D, Downes P, Devlin CV, Nixon GM, Devlin H.
The prevention of ‘dry socket’ with topical metronidazole in general dental practice. Br Dent J.
2006;200(4):210-213; discussion 206; quiz 226.
25. Al–Saffar MT, Al–Sandook TA, Suleiman MS. Protective
effect of topical ibuprofen against dry socket. Al–Rafidain Dent J. 2008;8(2):136-143.
26. Syrjanen SM, Syrjanen KJ. A new combination of
drugs intended to be used as a preventative measure
for the postextraction complications. A preliminary
report. Int J Oral Surg. 1981;10(1):17-22.
27.Poor MR, Hall JE, Poor AS. Reduction in the incidence of alveolar osteitis in patients treated with the
SaliCept Patch, containing Acemannan Hydrogel.
J Oral Maxillofac Surg. 2002;60(4):374-379; discussion 379.
28. Brekke JH, Olson RA, Scully JR, Osbon DB. Influence of
polylactic acid mesh on the incidence of localized osteitis. Oral Surg Oral Med Oral Pathol. 1983;56(3):
240-245.
29. Bloomer CR. Alveolar osteitis prevention by immediate
placement of medicated packing. Oral Surg Oral Med
Oral Pathol Oral Radiol Endod. 2000;90(3):282-284.
30. Suleiman AM. Influence of Surgicel gauze on the incidence of dry socket after wisdom tooth extraction.
East Mediterr Health J. 2006;12(3-4):440-445.
31. Schatz JP, Fiore-Donno G, Henning G. Fibrinolytic alveolitis and its prevention. Int J Oral Maxillofac Surg.
1987;16(2):175-183.
32. Pfizer, Inc. Gelfoam [product information]. Available at:
http://www.pfizer.com/files/products/uspi_gelfoam_
plus.pdf. Accessed March 18, 2015.
www.agd.org
33. Johnson & Johnson. Surgicel [product information].
Available at: http://www.ethicon.com/healthcareprofessionals/products/biosurgery/surgicel-family-ofabsorbable-hemostats/surgicel-original-absorbablehemostat#!overview. Accessed March 18, 2015.
34. Unicare Biomedical, Inc. BenaCel Dental Dressing
[product information]. Available at: http://www.
unicarebiomedical.com/dental-supplies/benacel.html.
Accessed March 18, 2015.
35. Swanson AE. A double-blind study on the effectiveness
of tetracycline in reducing the incidence of fibrinolytic
alveolitis. J Oral Maxillofac Surg. 1989;47(2):165-167.
36. Goldman DR, Kilgore DS, Panzer JD, Atkinson WH. Prevention of dry socket by local application of lincomycin
in Gelfoam. Oral Surg Oral Med Oral Pathol. 1973;
35(4):472-474.
37. Fridrich KL, Olson RA. Alveolar osteitis following surgical removal of mandibular third molars. Anesth Prog.
1990;37(1):32-41.
38. Johnson WS, Blanton EE. An evaluation of 9-aminoacridine/Gelfoam to reduce dry socket formation. Oral
Surg Oral Med Oral Pathol. 1988;66(2):167-170.
39. Huang WT, Lin MS, Yang S. Benacel for post-extraction
wound healing, Unicare Biomedical Internal Research
Report, May 9, 2011.
40. Nusair YM, Younis MH. Prevalence, clinical picture, and
risk factors of dry socket in a Jordanian dental teaching center. J Contemp Dent Pract. 2007;8(3):53-63.
Manufacturers
Johnson & Johnson, Skillman, NJ
800.690.1826, www.jnj.com
Pfizer, Inc., New York, NY
800.879.3477, www.pfizer.com
Unicare Biomedical, Inc., Laguna Hills, CA
949.305.9600, www.unicarebiomedical.com
There is another article on
EXODONTIA
in the online edition.
Management of uncommon
complications in seemingly routine
oral surgeries
Visit www.agd.org/GeneralDentistry
General Dentistry
May/June 2015
21
Nutrition
What every dentist should know about
artificial sweeteners and their effects
Zachary Aaron Starr n Judith A. Porter, DDS, EdD, FICD n Nasir Bashirelahi, PhD
Artificial sweeteners are a ubiquitous commodity on the market. The
idea that people can consume a sweet food or beverage with “zero”
calories seems too good to be true, and perhaps it is. The longevity and
abundance of these products on the market necessitate the study of their
T
oday’s evidence-based practice of
general dentistry demands a thorough understanding of the wide
variety of artificial sweeteners and their
physiological effects. Historically praised
for their decreased cariogenic potential
and caloric neutrality, artificial sweeteners
have recently been linked to alterations
in the gut microflora that may generate
glucose intolerance.1,2 Glucose intolerance
can lead to obesity, Type 2 diabetes, and
other expressions of metabolic syndromes.
Clinicians must weigh the sweeteners’
benefits as sugar-free dietary options
against these recently discovered risks.2
In 1879, Constantine Fahlberg discovered saccharin, which is 300 times sweeter
than sucrose, but has a bitter aftertaste.3
Saccharin, like most artificial sweeteners,
is not digested or absorbed and therefore
provides no caloric contribution to the
diet.4 In 1937, cyclamate was created but
later banned in the United States due to
its potentially carcinogenic properties.
Aspartame, an artificial sweetener
composed of 2 amino acids (phenylalanine
and aspartic acid), was discovered in 1965.
Aspartame is 200 times sweeter than
sucrose and lacks saccharin’s bitter aftertaste.3,4 Unlike other artificial sweeteners,
aspartame is digested and absorbed and
contributes 4 kcal per 1 g of aspartame.
FDA guidelines limit daily aspartame
intake to 50 mg/kg of body weight (192 oz
for adults and 96 oz for children).4
Sucralose (marketed as Splenda), which
is produced from sucrose, was discovered in 1979. Approved for use in food
and drink in 1999, it is the most widely
used artificial sweetener on the market
today and is 600 times sweeter than its
parent compound.3 Acesulfame potassium, another artificial sweetener which
22
May/June 2015
General Dentistry
mechanisms and their relationships to health and disease, including possible links to obesity, cardiovascular disease, and diabetes.
Received: October 27, 2014
Accepted: February 16, 2015
is 200 times sweeter than sucrose, was
approved by the FDA for use in food in
1988.4 Neotame surfaced in 2002 and
is the most potent artificial sweetener
on the market to date—7000 times
sweeter than sucrose.3 In terms of use in
food products, aspartame and acesulfame potassium rank second and third,
respectively, behind sucralose. Artificial
sweeteners are most commonly found in
carbonated beverages.3
It is worth noting the difference
between artificial sweeteners (such as
saccharin, sucralose, and aspartame)
and sugar alcohols (such as xylitol and
mannitol), which are found naturally in
foods and plant products. Sugar alcohols
provide minor caloric contributions when
ingested, separating them from most
artificial sweeteners.4
Digestion and absorption
of carbohydrates
The breakdown of carbohydrates begins
in the mouth with the mechanical
processing of food via chewing and the
addition of saliva to form a food bolus.
Salivary amylase proteins begin the breakdown of starch and polymers of simple
sugars into smaller chains of sugars.4
The bolus is then swallowed and driven
from the mouth through the pharynx,
esophagus, and stomach by peristaltic
movements.4 In the stomach, sugars are
not broken down but churned and mixed
to form a mass known as chyme. Chyme
passes to the duodenum, the first section
of the small intestine, where it meets a
secretion of sodium bicarbonate, a basic
solution that neutralizes acid. Further
along in the small intestine, enzymes
break down the sugar disaccharides into
their monosaccharide components; these
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are then absorbed through specialized
cells in the villi and transported into the
circulatory system.4
Glucose metabolism and satiation
Rising sugar levels in the bloodstream
cause beta cells in the pancreas to release
insulin into the blood. Insulin stimulates
somatic cells to take up more glucose and
hepatic cells to produce a storage product,
glycogen, from available glucose.5-7 A
homeostatic blood glucose level is considered to be approximately 90 mg per
100 ml. If blood glucose levels drop too
low, the alpha cells of the pancreas release
glucagon into the bloodstream, producing
effects opposite to those of insulin. The
opposing actions of these 2 hormones
keep glucose levels in a stable range.5-7 In
addition to insulin and glucagon, there
are other signals—such as glycoproteins
(such as GLP-1), hormones (such as
leptin and ghrelin), and other metabolic
products—that inform the body that it is
satisfied and can stop eating.5-7 This state
is known as satiation.
Satiation vs satiety
Satiation reflects the cumulative inhibitory feedback that the body has obtained
food.5 This feedback comes from digestive, hormonal, cognitive, and sensory
cues. When the body is sated, eating
usually comes to an end. The time from
when a person stops eating to the time of
hunger is known as satiety.5 Satiety is variable in duration, depending on the person
and the quantity and quality of food
consumed. During satiety, the brain’s sensory and cognitive (perceptive) processes
interact with the nutrients absorbed from
the ingested food.5 Satiety stimulates
negative feedback to keep the body in a
state where it physiologically does not feel
the need to eat, facilitating weight control. However, humans can override this
inhibitory effect.5
Overeating and the reward
pathway of the brain
A learned brain response can overwhelm
the body’s natural “off switch” to food
consumption and thus cause overeating. Found in the mesolimbic dopamine
pathway, this response acts as a reward
system that causes people to eat after
meals when they are not truly hungry.5
Exacerbated by stress, especially in those
with belly fat, this reward system allows
cues such as drugs, food, or sexual activity to increase dopamine signaling from
the nerves of the ventral tegmental area
(VTA) to the neurons in the ventral
striatal area of the brain.5 This same
pathway facilitates addiction to a specific
substance or activity.6
Additionally, the dopaminergic pathway
can be modulated through different signals in the body, including food. Sweet or
very tasty foods can stimulate dopamine
release. According to a study performed
by Lutter & Nestler, this dopaminergic
response to food is thought to intensify
the subject’s need for food rewards.6 This
need is demonstrated by increased arousal
of the VTA, psychomotor stimulation,
and classical conditioning due to foodassociated stimuli. Prolonged activation of
the reward pathway contributes to intracellular adaptations that serve to maintain
dopamine signaling homeostasis. Thus,
when the reward pathway is activated for
long periods of time, cells adapt in order
to keep up with the increased dopamine
levels being secreted in the brain.6
The adaptations observed in the VTA
neurons include inhibition of dopamine
secretion, neuronal shrinkage, increased
tyrosine hydroxylase activity, and increases
in the cyclic adenosine monophosphate
response element binding protein.6 These
adaptations are thought to be what
drives the heightened motivation to
secure controlled substances in addicted
patients. Similar adaptations have been
noted in rodents exposed to very desirable
foods for prolonged periods, suggesting
that motivation to obtain food rewards
can be changed by prolonged activation
of the mesolimbic dopamine (reward)
pathway in the brain.6 Humans may
exhibit an addiction-like response to food
by continually activating this reward
center in the brain.6
According to a 2010 study by Yang,
there are 2 pathways to food reward:
sensory (hedonic) and postprandial.3
The sensory pathway deals with the taste
of food: sweet flavors are perceived by
gustatory receptors.2,5 Recent research
has shown that sweet taste receptors are
found in not only the mouth but the
entire digestive tract.7 Signals ascend from
the gut to the thalamus, a relay station
for sensory and motor signals, and then
proceed to the gustatory cortex as well
as the frontal lobe of the brain, where
decision-making and expectation occur.5
The orbitofrontal cortex is also thought
to be an integral part of the perception
of rewards and punishment, resulting in
adaptive learning.3 The mesolimbic dopamine system is then activated to provide
a satisfied feeling after a pleasant taste.
The second pathway to food reward, the
postprandial branch, is dependent on the
body’s metabolism of food.3
Artificial sweeteners and satiety
Natural sweeteners (such as sugars and
sugar alcohols) are metabolized and
contribute calories to the body, activating
the postprandial pathway. When nonnutritive sweeteners—such as saccharin,
acesulfame potassium, and sucralose—are
ingested, they cannot be digested by the
body and therefore do not contribute
calories to the diet. While aspartame is
digested, its metabolites (aspartic acid,
phenylalanine, and methanol) do not
make the same contribution to the postprandial pathway.4 Thus, artificial sweeteners only activate the sensory (hedonic)
portion of the food reward system.
This partial activation may contribute
to an increased appetite by preparing the
body for calories from a sweet flavor but
not reinforcing that sweet flavor with
activation of the postprandial pathway.4
According to Fernstrom et al, the amygdala—a part of the limbic system that
contributes to the reward pathway—preferentially responds to beverages sweetened
with low-calorie sweeteners versus natural
sweeteners.8 Artificially sweetened beverages have also shown the ability to enhance
appetite and elevate the preference for
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sweet flavors.9 Artificial sweeteners “trick”
the body’s signals with a sweet taste but
yield no energy.3 This results in no feeling
of satiety. Satiety requires postabsorptive
feedback, and artificial sweeteners are
unable to provide the needed satisfaction.
Activating only the hedonic portion of
the food reward system may then cause
overeating to compensate for this biological
misconception, potentially continuing to
activate the mesolimbic dopamine pathway
in a vicious cycle.3
Artificial sweeteners and altered
gut microflora
Researchers have begun to look at the gut
as a “microbial” organ due to the large
number of microbial cells, which outnumber those of its human host.10 The gut’s resident microbial cells contribute a genome
that is 100-150 times greater than that of
the entire human genome.11 The resultant
expression of these microbial genes has
the power to affect host physiology.12,13
Thus, changes in gut microflora can lead
to changes in host physiology.12,14 A 2014
article published in General Dentistry
discusses the importance of maintaining a
healthy microbiome with probiotics and
the negative implications of antibiotic
misuse.14 Other studies have demonstrated
that the consumption of common artificial
sweeteners can alter gut microflora in both
animal and human models.2 Moreover, the
diversity and quantity of gut microorganisms are regulated by diet.12
Following human consumption of
artificial sweeteners, researchers have
noticed an overabundance of Bacteroides
species and an underrepresentation
of Clostridiales in some subjects.15
Similar microbiological patterns have
been associated with obese and Type
2 diabetes subjects.5,15 These findings
have led researchers to question whether
our eating behaviors, including moods
and cravings for specific foods, are also
influenced by this resident microbial
population.12 Alcock et al described
a “metagenomic conflict” that pits
microbes against hosts in a battle for survival in which both sides are influenced
by selective evolutionary pressures.12
However, research remains inconclusive
overall because each subject’s gut microflora response to diet—and specifically
artificial sweeteners—is unique.2
General Dentistry
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23
Nutrition What every dentist should know about artificial sweeteners and their effects
Association of cardiovascular
disease with artificial sweeteners
The American Heart Association and the
American Diabetes Association released
the results of a National Health Survey
that stated that people who consume 2
or more servings of artificially sweetened beverages per day had an associated increased risk for cardiovascular
disease and chronic kidney disease.16
This finding was true when compared
with people who drank ≤1 artificially
sweetened beverage per month over an
11-12 year span.16,17
Effect of artificial sweeteners
on glycemic control
A 2009 statement from the American
Heart Association and American Diabetes
Association addressed glycemic control and
artificial sweeteners.18 Because many health
organizations recommend decreasing sugar
consumption to promote glycemic control,
many people are turning toward artificially
sweetened beverages to give them the
desired sweet flavor without the calories or
spikes in blood glucose levels.18 However,
after much research, the data are insufficient to determine if artificially sweetened
beverages are the silver bullet they were
intended to be. They appear to decrease
sugar intake, but their negligible energy
contribution may contribute to metabolic
disturbances, especially if compensatory
mechanisms are in place to acquire energy
from other sources.18
One theory posits that the use of nonnutritive sweeteners enhances appetite
to the point that the calories and carbohydrates “saved” from drinking the artificially sweetened beverage are nullified
due to increased caloric consumption
after a sugar-free beverage or snack.19 A
study by Mattes & Popkin examined the
effects of artificial sweeteners on appetite
and food consumption.19 Eight plausible
mechanisms for increased appetite and
food consumption were evaluated, but
the data collected proved insufficient to
determine a causal relationship among
the 3 variables.19 However, other studies found that sucralose ingestion did
not stimulate the release of satiating
glycoproteins (such as GLP-1) and did
not reduce appetite.20,21 Furthermore,
artificial sweeteners and Type 2 diabetes
mellitus were examined in an attempt to
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General Dentistry
prove a corollary relationship in at least
4 studies.9,22-24 While 2 studies showed
no association, 2 other studies showed a
significant correlation between artificial
sweeteners and Type 2 diabetes.9,22-24
Discussion
Food manufacturers have invested
significant money and effort into the
development of artificial sweeteners in
an attempt to satisfy both the consumers’ addiction to sweetness and their
avoidance of calories. The widespread
use of these sweeteners has compelled
researchers to investigate any possible
harmful effects to the body. With the
recent discovery of artificial sweeteners’ ability to influence gut microbiota,
scientists are closer to establishing a link
between artificial sweetener consumption and an increased risk for metabolic
disease. In their efforts as clinicians
to provide care in the most current
evidence-based approach, dentists should
share this information and provide personalized counseling to those patients
who must monitor their glucose levels
or are at high risk for caries. Simply telling patients to substitute sugar intake
with artificial sweeteners could be
deemed as malpractice and is not in line
with current research. Instead, dentists
should focus on other dietary suggestions, such as enjoying “sweet” foods
in moderation, limiting “real” sugar
consumption to meals, and avoiding
long-term exposure to sugar throughout
the day. It is the authors’ opinion that if
patients desire sugar substitutes, dentists
should emphasize consumption in moderation and a preference for sweeteners
from natural sources.
Conclusion
Artificial sweeteners, seemingly harmless
food additives, preferentially activate
a reward pathway for sweet flavors.
Activation of this pathway can cause
compensatory overeating that may nullify
the rationale for artificial sweetener use.
Artificial sweeteners may also increase
the risk for developing obesity, Type 2
diabetes, and other manifestations of
metabolic disorders due to their ability
to influence gut microflora, but more
investigation needs to be done in order to
determine causality.
www.agd.org
Author information
Mr. Starr is a doctoral candidate at
the University of Maryland School of
Dentistry, Baltimore, where Dr. Porter
is the assistant dean of admissions and
recruitment. Dr. Bashirelahi is a professor of biochemistry, Dental and Medical
Schools of the University of Maryland.
Acknowledgment
We would like to thank Michele Nance
of the Reference & Research Services
Department of the University of Maryland
Health Sciences & Human Services
Library for her aid in the preparation of
this article.
References
1. Giacaman RA, Campos P, Munoz-Sandoval C, Castro
RJ. Cariogenic potential of commercial sweeteners in
an experimental biofilm caries model on enamel. Arch
Oral Biol. 2013;58(9):1116-1122.
2. Suez J, Korem T, Zeevi D, et al. Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature. 2014;514(7521):181-186.
3. Yang Q. Gain weight by “going diet?” Artificial sweeteners and the neurobiology of sugar cravings: neuroscience 2010. Yale J Biol Med. 2010;83(2):101-108.
4. Insel P, Ross D, McMahon K, Bernstein M. Discovering
Nutrition. 4th ed. Burlington, MA: Jones & Bartlett
Learning; 2013.
5. Bellisle F, Drewnowski A, Anderson GH, WesterterpPlantenga M, Martin CK. Sweetness, satiation, and
satiety. J Nutr. 2012;142(6):1149S-1154S.
6. Lutter M, Nestler EJ. Homeostatic and hedonic signals
interact in the regulation of food intake. J Nutr. 2009;
139(3):629-632.
7. Gerspach AC, Steinert RE, Schonenberger L, GraberMaier A, Beglinger C. The role of the gut sweet taste
receptor in regulating GLP-1, PYY, and CCK release in
humans. Am J Physiol Endocrinol Metab. 2011;301(2):
E317-E325.
8. Fernstrom JD, Munger SD, Sclafani A, de Araujo IE,
Roberts A, Molinary S. Mechanisms for sweetness.
J Nutr. 2012;142(6):1134S-1141S.
9. Fagherazzi G, Vilier A, Saes Sartorelli D, Lajous M, Balkau
B, Clavel-Chapelon F. Consumption of artificially and
sugar-sweetened beverages and incident type 2 diabetes in the Etude Epidemiologique Aupres des Femmes
de la Mutuelle Generale de l’Education Nationale-European Prospective Investigation into Cancer and Nutrition cohort. Am J Clin Nutr. 2013; 97(3):517-523.
10. Backhed F, Ley RE, Sonnenburg JL, Peterson DA, Gordon JI. Host-bacterial mutualism in the human intestine. Science. 2005;307(5717):1915-1920.
11. Qin J, Li R, Raes J, et al. A human gut microbial gene
catalogue established by metagenomic sequencing.
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12. Alcock J, Maley CC, Aktipis CA. Is eating behavior
manipulated by the gastrointestinal microbiota? Evolutionary pressures and potential mechanisms. Bioessays. 2014;36(10):940-949.
13. David LA, Maurice CF, Carmody RN, et al. Diet rapidly
and reproducibly alters the human gut microbiome.
Nature. 2014;505(7484):559-563.
14. Klish AJ, Porter JA, Bashirelahi N. What every dentist
needs to know about the human microbiome and probiotics. Gen Dent. 2014;62(1):30-36.
15. Backhed F, Ding H, Wang T, et al. The gut microbiota as
an environmental factor that regulates fat storage.
Proc Natl Acad Sci USA. 2004;101(44):15718-15723.
16. Gardner C, Wylie-Rosett J, Gidding SS, et al. Nonnutritive sweeteners: current use and health perspectives: a
scientific statement from the American Heart Association and the American Diabetes Association. Circulation. 2012;126(4):509-519.
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22. Schulze MB, Manson JE, Ludwig DS, et al. Sugarsweetened beverages, weight gain, and incidence of
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General Dentistry
May/June 2015
25
Orthodontics
Kinetics of salivary pH after acidic beverage intake
by patients undergoing orthodontic treatment
Cecilia P. Turssi, DDS, MS, PhD n Carolina S. Silva, DDS n Enrico C. Bridi, DDS n Flavia L.B. Amaral, DDS, MS, PhD Fabiana M.G. Franca, DDS, MS, PhD n Roberta T. Basting, DDS, MS, PhD
The saliva of patients undergoing orthodontic treatment with fixed
appliances can potentially present a delay in the diluting, clearing,
and buffering of dietary acids due to an increased number of retention
areas. The aim of this clinical trial was to compare salivary pH kinetics of
patients with and without orthodontic treatment, following the intake
of an acidic beverage. Twenty participants undergoing orthodontic
treatment and 20 control counterparts had their saliva assessed for flow
rate, pH, and buffering capacity. There was no significant difference
between salivary parameters in participants with or without an
orthodontic appliance. Salivary pH recovery following acidic beverage
T
he risk of developing carious lesions
during orthodontic treatment with
fixed appliances is high.1-4 Such risk
is related to the presence of brackets, arch
wires, and other orthodontic appliances
that hinder appropriate oral hygiene.5-7
Considering that orthodontic treatment
is usually performed on children and adolescents, who are generally the major consumers of soft drinks and fruit juices, there
is concern about the potential of such
beverages to increase the risk of dental
erosion in patients undergoing orthodontic treatment.8 This concern increases
when one considers the growing body of
evidence that correlates soft drink intake
with dental erosion.9-11 A clinical study by
Prietsch et al reported severe dental erosion
around orthodontic brackets as a result of
the high intake of an acidic soft drink.12
The pathology of dental erosion involves
interplay among chemical, biological,
and behavioral factors and entails the
progressive and irreversible dissolution of
the outer layer of the dental tissues and
demineralization of the underlying surface.13,14 Among the chemical factors, pH,
titratable acidity, and calcium-chelating
properties influence the erosive potential
of acidic beverages.15 Saliva is the principal
biological factor, which acts by diluting,
clearing, and buffering acids and providing
electrolytes.16 These protective functions
are especially important, as the erosiveness
of acidic beverages is time-dependent;
saliva provides intraoral pH recovery after
26
May/June 2015
General Dentistry
intake was slower in the orthodontic subjects compared to controls.
Patients with fixed orthodontic appliances, therefore, seem to be
at higher risk of dental erosion, suggesting that dietary advice and
preventive care need to be implemented during orthodontic treatment.
Received: October 4, 2013
Revised: December 9, 2013
Accepted: January 23, 2014
acidic insults, thus playing a crucial role in
controlling the erosive process.17-21 Thus,
an understanding of the kinetics of salivary
pH following acidic beverage intake would
provide a valuable insight into the physiopathology of dental erosion.
Although some studies have measured
salivary pH after exposure to acidic beverages or solutions, none have yet monitored
the salivary pH of patients undergoing
orthodontic treatment with fixed appliances.19,20,22-27 In these patients, the diluting, clearing, and buffering actions of
saliva may be delayed due to an increased
number of retention areas. Based on this
rationale, the aim of this clinical trial was
to evaluate the salivary pH kinetics of
patients undergoing orthodontic treatment
after sipping an acidic beverage.
Materials and methods
Study outline
This randomized, controlled study followed a combination of parallel-arm and
crossover designs. Twenty participants
undergoing orthodontic treatment with
metallic, fixed appliances in both arches
and 20 not undergoing orthodontic treatment were included. All participants had
their unstimulated and stimulated whole
saliva evaluated for flow rate, pH, and
buffering capacity. Half of the participants
of each group were then instructed to sip
but not swallow 15 ml of orange juice,
then switch to distilled water with 5%
sucrose added. The remaining participants
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Key words: dental erosion, saliva, pH,
acidic beverage, orthodontic patients
performed the reverse sequence. The pH
of the saliva-beverage mixture was assessed
at 15 points in time.
Subjects and ethical aspects
The protocols were reviewed and approved
by the Sao Leopoldo Mandic Institute and
Dental Research Center ethics committee
(No. 2011/0418). Written, informed consent to the protocols was obtained from
each participant. Volunteers were eligible
if they exhibited good conditions of oral
hygiene and normal flow rates of stimulated saliva. Volunteers for the group of
patients undergoing orthodontic treatment
were eligible if they were wearing metallic
fixed appliances in both dental arches.
Volunteers were excluded if they presented
with tooth wear lesions, active caries,
extensive direct restorations, indirect restorations, periodontal disease, or reflux disease. Subjects were further excluded if they
were wearing removable orthodontic appliances, were taking regular medications,
or had any systemic diseases. Smokers
and patients suffering from alcoholism, in
addition to pregnant and/or breastfeeding
women, were also excluded.
Flow rate, pH, and buffering
capacity of saliva
Two days prior to commencing, each
participant was required to use only the
toothpaste and soft-bristle toothbrush provided for the study, refraining from using
any other oral product.
Table 1. Salivary parameters measured for control and orthodontic subjects
in the study.
Subjects
Salivary parameters
Flow rate (ml/min)
Control (SD)
Orthodontic (SD)
Mean (SD)
Unstimulated
0.60 (0.47)
0.41 (0.28)
0.51 (0.40) a
Stimulated
1.45 (0.62)
Unstimulated
6.63 (0.39)
Stimulated
7.18 (0.23)
Unstimulated
3.57 (1.16)
Stimulated
4.53 (1.18)
Student’s t test: P = 0.14
1.59 (0.54)
1.52 (0.58) b
Student’s t test: P = 0.46
pH
6.70 (0.20)
6.66 (0.31) a
Student’s t test: P = 0.52
7.05 (0.25)
7.12 (0.25) b
Student’s t test: P = 0.11
Buffering capacity
(pH)
2.98 (0.37)
3.29 (0.91) a
Student’s t test: P = 0.06
4.69 (0.94)
4.61 (1.06) b
Student’s t test: P = 0.65
Means followed by different lowercase superscript letters denote significant differences between unstimulated and
stimulated saliva for each salivary parameter. Abbreviation: SD, standard deviation.
Saliva was collected between 8:30 and
11:30 am. All subjects abstained from
eating, drinking, or performing any
oral hygiene for 2 hours prior to collection. Once seated upright in a chair, the
subjects relaxed for 5 minutes and were
instructed during the collection to make
as few movements as possible, including
swallowing. All subjects contributed 1
sample each of unstimulated and stimulated whole saliva. Before the collection,
disposable cups were weighed on an electronic scale (ASF11, Marte Cientifica).
For unstimulated saliva, subjects were
instructed to sit with their heads slightly
down and drain their saliva into 1 of the
pre-weighed disposable cups as passively
as possible. After 5 minutes of collection,
the disposable cup was reweighed. The
flow rate was calculated in g/minute,
which is effectively equivalent to ml/
minute. After collection, the unstimulated saliva was also evaluated for pH,
measured using a 3 mm diameter calomel
microelectrode (Accumet EW-5550045, Cole-Parmer) connected to a digital
pH meter (W3B, Bel Equipamentos
Analiticos LTDA). Salivary buffering
capacity was measured as follows. The
collected saliva was mixed by inverting
the covered disposable cup 5 times, and
1 ml of saliva was then transferred to 3
ml of a 5 mM HCl solution. The mixture
was then vortexed for 5 seconds, and the
disposable cup was uncovered to allow
CO2 to escape; after 5 minutes, the pH
of the saliva/HCl mixture was measured
using the Accumet EW-55500-45.
After the collection of the unstimulated
saliva, subjects were instructed to chew
for 30 seconds on a 5 x 5 cm2 piece of
paraffin. The saliva produced during this
time was then swallowed before the collection was started. Chewing was resumed
for 5 minutes, with saliva spat out at short
intervals into pre-weighed disposable
cups. Samples of stimulated saliva were
also measured for flow rate, pH, and buffering capacity.
Monitoring of salivary pH
Half of the orthodontic subjects and half
of the controls were randomly assigned
to initially sip 15 ml of orange juice (Fast
Fruit Gourmet, GlobalFruit) with a pH
of 3.6 and high buffering capacity. The
orange juice was at room temperature
and kept in the mouth for 10 seconds
after which volunteers spat out the orange
juice/saliva mixture into disposable
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screw-capped plastic tubes. Samples of this
mixture were collected at 14 time points
following the first spitting: 15, 30, 45, 60,
90, 120, 150, 180, 210, 240, 270, 300,
360, and 420 seconds. In total, the orange
juice/saliva mixture was spat out 15 times:
at 10 seconds after sipping, then every
15 seconds up to 1 minute, next every
30 seconds up to 5 minutes, and finally
at 6 and 7 minutes. The participants were
asked not to swallow during the time span
covered. The pH of each of the 15 samples
was measured immediately after spitting,
using the calomel microelectrode.
The remaining subjects sipped distilled
water with 5% sucrose added (pH 5.8),
following exactly the same procedures as
described above.
Following a 1-day washout period, volunteers switched to sip the other beverage.
Thus, half of the participants performed
the sequence of orange juice first, switching to distilled water with 5% sucrose
added (pH 6.1), while the remainder performed the reverse sequence.
Statistical analysis
A Student’s t test was applied to assess
differences in salivary parameters between
participants undergoing orthodontic treatment and those not undergoing orthodontic treatment.
The pH values of the saliva samples
collected at the different time intervals
were evaluated with a 3-way ANOVA for
repeated measurements and with Tukey’s
test. The significance level was set at 5%.
Statistical calculations were performed using
SPSS version 20 software (SPSS, Inc.).
Results
The Student’s t test demonstrated no
significant difference in salivary parameters
in either the orthodontic subjects or the
controls (Table 1).
Three-way ANOVA of repeated measurements demonstrated a significant
interaction between metallic fixed orthodontic appliances and time after sipping
(P < 0.001). Tukey’s test demonstrated
that when subjects sipped water, the salivary pH values in the orthodontic subjects
did not differ from those measured in the
controls, regardless of the time interval.
For the control subjects, sipping orange
juice kept salivary pH significantly lower
than sipping the distilled water with
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May/June 2015
27
Orthodontics Kinetics of salivary pH after acidic beverage intake by patients undergoing orthodontic treatment
5% sucrose added for up to 60 seconds,
during which the salivary pH was below
the critical value for enamel (pH 5.5) for
30 seconds. For the orthodontic subjects,
sipping orange juice kept salivary pH significantly lower than sipping the distilled
water with 5% sucrose added for up to
210 seconds, during which time the salivary pH was below the critical value for
enamel for 60 seconds (Table 2).
The Chart depicts the kinetics of salivary pH of the orthodontic and control
groups according to the beverage sipped.
Salivary pH presented a significant
exponential drop, followed by a pH rise
to the basal salivary pH values, and was
succeeded by a leveling off as a result of
orange juice sipping.
Discussion
This trial was designed to test whether the
presence of metallic, fixed, orthodontic
appliances would retard salivary pH
recovery following acidic beverage intake.
Orange juice was the beverage of choice as
it presents a high buffering capacity, causing saliva to require longer periods of time
to neutralize it than other beverages.28-30
In addition, the erosive capacity of orange
juice has previously been demonstrated.31
Distilled water with 5% sucrose added
was used as the control beverage instead
of plain water. This experimental component was an attempt to calibrate the
potential gustatory stimulation of saliva
provided by both beverages, since orange
juice typically has around 5% sucrose
occurring naturally.32
Although salivary parameters did
not differ between the orthodontic and
control subjects, after sipping orange
juice, the presence of the orthodontic
appliances doubled the time during which
salivary pH was below the critical pH
for enamel. For the control subjects, the
pH remained below 5.5 for 30 seconds,
while the salivary pH remained below
5.5 for 60 seconds for the orthodontic
subjects. This increase may be attributed
to the presence of brackets and arch wires,
which create more retentive areas and
thereby reduce the effectiveness of saliva
in clearing and diluting acids. In addition,
fixed orthodontic appliances may potentially preclude the friction exerted by soft
tissues, which are known to displace soft
drinks adhered to enamel.33
28
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General Dentistry
Table 2. Kinetics of salivary pH of control and orthodontic subjects in the study.
Mean salivary pH
Distilled water with 5% sucrose added
Orange juice
Time (s)
Control (SD)
Orthodontic (SD)
Control (SD)
Orthodontic (SD)
0
6.30 (0.58)
a
6.38 (0.43)
a
3.72 (0.15)
3.61 (0.24) b
15
6.65 (0.74)
a
6.72 (0.29)
a
4.78 (0.43)
30
6.73 (0.80) a
6.71 (0.26) a
5.48 (0.43) b*
4.95 (0.84) c
45
6.66 (0.72)
6.68 (0.34)
5.93 (0.43)
5.21 (0.79) c
60
6.66 (0.80) a
6.63 (0.30) a
6.01 (0.43) b¥
5.46 (1.02) c*
90
6.66 (0.65)
6.60 (0.34)
6.32 (0.43)
a
5.87 (0.93) b
120
6.63 (0.52) a
6.56 (0.39) a
6.45 (0.43) a
5.94 (0.84) b
150
6.56 (0.58)
6.55 (0.36)
6.51 (0.43)
a
6.04 (0.84) b
180
6.58 (0.48) a
6.50 (0.41) a
6.54 (0.43) a
6.11 (0.74) b
210
6.58 (0.37)
6.48 (0.43)
6.61 (0.43)
a
6.19 (0.68) b¥
240
6.63 (0.43) a
6.48 (0.39) a
6.60 (0.43) a
6.22 (0.68) a
270
6.53 (0.37)
6.46 (0.45)
6.63 (0.43)
a
6.23 (0.70) a
300
6.52 (0.37) a
6.48 (0.41) a
6.68 (0.43) a
6.31 (0.66) a
360
6.54 (0.32)
6.47 (0.42)
6.66 (0.43)
a
6.31 (0.60) a
420
6.55 (0.27) a
6.70 (0.43) a
6.32 (0.60) a
a
a
a
a
a
a
a
a
a
a
a
a
6.49 (0.46) a
b
b
b
4.61 (0.92) b
Means followed by different lowercase superscript letters denote significant differences within a row. *pH value in
relation to critical pH of enamel. ¥ pH value in relation to critical pH of dentin. Abbreviation: SD, standard deviation.
The current results showed that salivary
pH substantially dropped in the first
15 seconds for both the orthodontic and
control subjects. These 2 curves, however,
deviated from one another over time, as
the control subjects demonstrated faster
recoveries of their salivary pH values. In
fact, after 60 seconds, the salivary pH after
sipping orange juice did not differ from
that after sipping distilled water with 5%
sucrose added. Conversely, among the
orthodontic subjects, at 210 seconds the
salivary pH—as a consequence of orange
juice intake—remained significantly lower
than that observed for distilled water with
5% sucrose added. Therefore, among the
orthodontic subjects, not only was the
salivary pH below the critical value for
enamel for twice the amount of time when
sipping orange juice, it remained significantly lower for 3.5 times longer in comparison to the scenario in which distilled
water with 5% sucrose added was sipped.
In this study, salivary pH was monitored using a microelectrode in samples
of beverage/saliva mixture spat out into
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containers. The major advantage of
this methodology was the possibility of
measuring salivary pH within short time
intervals in low saliva volumes and in a
very simple manner. In some studies, pH
electrodes were held in vacuum-formed
splints.20,23,24 The main drawback of such
splints is that they can increase salivary
flow rate and, therefore, salivary buffering capacity.24 In other studies, intraoral
pH was recorded using the microtouch
method in which electrode tips are placed
on the tooth surface.19,25-27 However,
despite the fact that there were no splints,
the electrode tips had to be repositioned
at different sites within the oral cavity.27
Therefore, using the microtouch method
somewhat hinders data acquisition when
used within short time periods, such
as those in which acidic beverages are
kept in the mouth.20,26 In addition, with
the microtouch method, a salt bridge
needs to be established between a reference electrode and the subject’s finger.27
Another method found in the literature
for measuring salivary pH refers to the
Chart. Salivary pH observed in control and orthodontic patients.
7
pH
6
5
Patients not undergoing orthodontic treatment following
sipping of distilled water with 5% sucrose added
Patients undergoing orthodontic treatment following
sipping of distilled water with 5% sucrose added
4
Patients not undergoing orthodontic treatment following
sipping of orange juice
Patients undergoing orthodontic treatment following
sipping of orange juice
3
Base 0
15
30
45
60
90 120 150 180 210 240 270 300 360 420
Time (seconds)
usage of telemetry systems from which
continuous readings are taken.25 The
main drawback of such telemetric measurements is the requirement of skin
reference electrodes, which need to be
attached to a subject’s arm.
It is important to note that the pH
recorded when analyzing the orange
juice/saliva mixture in this study
reflected the overall pH of the oral cavity
and not the values of site-specific locations, which may retain acids distinctively.22 Therefore, it is possible that acids
may be retained longer on dental surfaces
than in total saliva, which would create a
more problematic erosive scenario, especially in fixed orthodontic patients. In
addition, under real-life conditions, not
only would one sip be taken but rather
repeated sips, therefore increasing the
contact time between the beverages and
the oral tissues.
Conclusion
Based on the current findings, salivary
pH recovery after acidic beverage intake
was found to be slow in patients undergoing orthodontic treatment with fixed
appliances, potentially placing them at
higher risk of dental erosion. Therefore,
dietary advice and preventive care should
be directed toward patients undergoing
orthodontic treatment.
Author information
Drs. Turssi, Amaral, Franca, and Basting are
assistant professors, Division of Cariology
and Restorative Dentistry, Sao Leopoldo
Mandic Institute and Dental Research
Center, Campinas, Brazil, where Dr. Bridi
is a masters student, Division of Cariology
and Restorative Dentistry, and Dr. Silva is a
masters student, Division of Orthodontics.
Acknowledgments
The authors are especially grateful for the
valuable participation and cooperation of
the volunteers. Thanks are also given to
Tatiana Ricci and Lucimar Cruz for their
technical assistance.
Disclaimer
The authors have no financial, economic,
commercial, and/or professional interests
related to topics presented in this article.
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17. Amaechi BT, Higham SM, Edgar WM. Factors influencing the development of dental erosion in vitro: enamel
type, temperature and exposure time. J Oral Rehabil.
1999;26(8):624-630.
18. Eisenburger M, Addy M. Evaluation of pH and erosion
time on demineralisation. Clin Oral Investig. 2001;
5(2):108-111.
19. Johansson AK, Lingstrom P, Birkhed D. Comparison of
factors potentially related to the occurrence of dental
erosion in high- and low-erosion groups. Eur J Oral
Sci. 2002;110(3):204-211.
20. Millward A, Shaw L, Harrington E, Smith AJ. Continuous monitoring of salivary flow rate and pH at the surface of the dentition following consumption of acidic
beverages. Caries Res. 1997;31(1):44-49.
21. Lindquist B, Lingstrom P, Fandriks L, Birkhed D. Influence of five neutralizing products on intra-oral pH after rinsing with simulated gastric acid. Eur J Oral Sci.
2011;119(4):301-304.
22. Bashir E, Gustavsson A, Lagerlof F. Site specificity of
citric acid retention after an oral rinse. Caries Res.
1995;29(6):467-469.
23. Moazzez R, Smith BG, Bartlett DW. Oral pH and
drinking habit during ingestion of a carbonated drink
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Orthodontics Kinetics of salivary pH after acidic beverage intake by patients undergoing orthodontic treatment
in a group of adolescents with dental erosion. J Dent.
2000;28(6):395-397.
24. Bartlett DW, Bureau GP, Anggiansah A. Evaluation of
the pH of a new carbonated soft drink beverage: an in
vivo investigation. J Prosthodont. 2003;12(1):21-25.
25. Johansson AK, Lingstrom P, Imfeld T, Birkhed D. Influence of drinking method on tooth-surface pH in relation
to dental erosion. Eur J Oral Sci. 2004;112(6):484-489.
26. Hassan L, Wilson R, Bartlett D. Comparison of acid
clearance of noncarbonated and carbonated soft drinks
in the mouth. Int J Prosthodont. 2007;20(2): 181-182.
27.Lussi A, von Salis-Marincek M, Ganss C, Hellwig E,
Cheaib Z, Jaeggi T. Clinical study monitoring the pH
on tooth surfaces in patients with and without erosion. Caries Res. 2012;46(6):507-512.
28. Zero DT, Lussi A. Erosion—chemical and biological
factors of importance to the dental practitioner. Int
Dent J. 2005;55(4 Suppl 1):285-290.
29. Edwards M, Creanor SL, Foye RH, Gilmour WH. Buffering capacities of soft drinks: the potential influence
on dental erosion. J Oral Rehabil. 1999;26(12):923927.
30. Lussi A, Jaeggi T, Zero D. The role of diet in the aetiology of dental erosion. Caries Res. 2004;38(Suppl 1):
34-44.
30
May/June 2015
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31. Lussi A, Kohler N, Zero D, Schaffner M, Megert B. A
comparison of the erosive potential of different beverages in primary and permanent teeth using an in
vitro model. Eur J Oral Sci. 2000;108(2):110-114.
32. Baldwin EA, Bai J, Plotto A, et al. Effect of extraction
method on quality of orange juice: hand-squeezed,
commercial-fresh squeezed and processed. J Sci Food
Agr. 2012;92(10):2029-2042.
33. Ireland AJ, McGuinness N, Sherriff M. An investigation into the ability of soft drinks to adhere to enamel. Caries Res. 1995;29(6):470-476.
Manufacturers
Bel Equipamentos Analiticos LTDA, Piracicaba, Brazil
19.3435.3534, www.beleng.com.br
Cole-Parmer, Vernon Hills, IL
800.323.4340, www.coleparmer.com
GlobalFruit, Visconde do Rio Branco, Minas Gerais, Brazil
55.32.3551.8200, www.globalfruit.com.br
Marte Cientifica, Sao Paulo, Brazil
55.11.3411.4500, www.marte.com.br
SPSS, Inc., Chicago, IL
312.651.3000, www.spss.com
www.agd.org
AGDPODCAST
Orthodontics:
Six Month Smiles
Dental Materials
Nanoleakage of fiber posts luted with
different adhesive strategies and the effect
of chlorhexidine on the interface of dentin
and self-adhesive cements
Danielson Guedes Pontes, DDS, MS n Cintia Tereza Pimenta Araujo, DDS, MS n Lucia Trazzi Prieto, DDS, MS Dayane Carvalho Ramos Salles de Oliveira, DDS, MS n Erick Kamiya Coppini, DDS, MS n Carlos Tadeu Santos Dias, DDS, MS, PhD Luis Alexandre Maffei Sartini Paulillo, DDS, MS, PhD
The aim of this in vitro study was to evaluate the nanoleakage of
fiber posts luted using different adhesive strategies and to investigate
the effect of 2% chlorhexidine (CHX) on nanoleakage at the resindentin interfaces of self-adhesive cements. The self-adhesive and
etch-and-rinse adhesive groups tested demonstrated similar results
with regard to nanoleakage. Pretreatment with CHX promoted an
F
iber posts are widely used to restore
endodontically treated teeth.1,2 Glass
fiber posts are biocompatible, do not
corrode, and offer the most favorable optical properties for reproducing the natural
aspect of the restored tooth.3 Resin cements
have been widely used for luting fiber
posts due to their enhanced mechanical
properties.4 Several factors play a role in
the intraradicular bonding of resin-based
materials.5 The peculiar histological characteristics of root dentin, the presence of
endodontic smear layers (created either by
endodontic instruments or modified by
irrigants), and adverse geometric factors—
such as the extremely high cavity configuration (C-factor) and the difficult to achieve
direct irradiation by light in deep regions of
the root canal—are consistent factors that
negatively affect the bonding of glass fiber
posts to root canal dentin.6-9 In addition,
the type of bonding system used, the luting
cement, and its cure may interfere with
hybrid layer formation along the root canal
walls, thus affecting post retention.10,11 This
hybridization is critical in the apical third
of the post space due to the difficulty in
establishing adhesion in this area.12
Traditional resin cements with chemical
or dual activation are commonly used to
overcome problems in supplying the necessary irradiation of light into the root canal.9
However, alternative adhesive strategies—
such as luting systems with self-etching
adhesives—are less complex since these
adequate seal at the resin-dentin interface for self-adhesive cements.
Received: July 25, 2013
Accepted: November 12, 2013
Key words: nanoleakage, self-adhesive
cement, chlorhexidine, fiber post
self-etch adhesives are generally applied on
dry dentin and do not require the additional step of rinsing with phosphoric acid,
thus eliminating the problem of dentin
wetness control.13 Compared to the traditional resin cements, self-etching adhesives
require no previous treatment of the dental
substrate, since the stages of acid etching
and adhesive system application have been
eliminated.14 The bonding mechanism of
self-adhesive cements is based on micromechanical retention and chemical adhesion.4
When self-adhesive cements are bonded
to dentin, there is a rapid change in pH
(ranging from 2.0 to 2.4) that causes an
early activation of the matrix metalloproteinase (MMP), along with increased collagenolytic activity (approaching maximum
levels).15,16 During dentin demineralization, latent MMP is denatured as more
proteases are exposed.16 As a result, collagen fibrils that are not completely protected by resin monomers during dentin
hybridization become highly susceptible to
hydrolytic degradation.4
Chlorhexidine (CHX) has been shown
to have an inhibitory effect on endogenous collagenolytic activity in dentin.17
Although CHX diminishes the loss of
bond strength over time, not much is
known about the influence of a CHX solution—when applied prior to the cementation of indirect restorations—on the
integrity of the bonded interface formed
by self-adhesive cements to root dentin.18
www.agd.org
In 2009, Hiraishi et al speculated that the
deterioration of the bonding efficacy of
commercial self-adhesive luting cements
might be related to the presence of moisture contamination on the dentin surface.19 Hence, it is of interest to examine
the influence of different luting systems
and the effect of 2% CHX on the nanoleakage at the cement-dentin interface.
Materials and methods
Thirty bovine roots were stored for 7 days
in a saturated thymol solution at 5°C
for disinfection and used within 1 week
postextraction. The roots’ inclusion criteria
were completely formed apices, without
excessive root curvature, and root canals
with a diameter smaller than the diameter of a Largo No. 5 bur (DENTSPLY
Maillefer), cut to the length of 17 mm.
Teeth were divided into 6 experimental
groups (n = 3) and restored with different
cementation techniques (Table 1).
Endodontic treatment
For endodontic treatment, a step-back preparation technique was used with stainless
steel K-files and Gates-Glidden burs (No.
3-5) (Miltex, Inc.) at the working length;
the roots were irrigated with distilled water
after every change of instrument. Roots were
dried with paper points and filled with gutta
percha cones (DENTSPLY Maillefer) using
the lateral condensation technique. The
roots were stored in distilled water at 37°C.
General Dentistry
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31
Dental Materials Nanoleakage of fiber posts luted with different adhesive strategies
Post luting procedures
The next step involved the removal of
the gutta percha, leaving at least 5 mm of
the endodontic filling at the apex of each
canal. The post spaces were prepared to
a distance of 10 mm from the cementoenamel junction, using a No. 4 Largo drill
(DENTSPLY Maillefer). The roots were
separated randomly into 6 experimental
groups (n = 3) according to the luting
system used: Group 1, Scotchbond MultiPurpose Plus (3M ESPE) chemical cure
etch-and-rinse adhesive + RelyX ARC
dual-cured cement (3M ESPE); Group 2,
Clearfil SE Bond (Kuraray America, Inc.)
self-etching adhesive + ED Primer (Kuraray
America, Inc.) dual cure + Panavia F dualcured cement (Kuraray America, Inc.);
Group 3, Clearfil SE Bond s physical cure
+ Panavia F; Group 4, Scotchbond MultiPurpose Plus physical cure + RelyX ARC;
Group 5, RelyX U100 self-adhesive cement
(3M ESPE); Group 6, RelyX Unicem (3M
ESPE) self-adhesive cement.
The glass fiber posts (Reforpost, Angelus
Industria de Produtos Odontologicos
S/A) were cleaned with 70% alcohol for
1 minute, then dried. Afterward, a silane
coupling agent (Silano Angelus, Angelus
Industria de Produtos Odontologicos
S/A) was applied on each post surface
for 1 minute; then, the posts in each of
the 6 groups were luted following their
respective manufacturer’s instructions
(Table 2). The materials were manipulated
and inserted into the canal with a Centrix
syringe with a metallic tip (Centrix, DFL
Industria e Comercio). RelyX Unicem was
applied with a capsule and elongation tip
provided by the manufacturer. For activation purposes, the dual-cure cements and
adhesive systems were cured from the top
of the post with a halogen curing light unit
(Optilux 501, Kerr Corporation) at 600
mW/cm2. To simulate clinical conditions,
a wax protection barrier was applied to the
external surface of the roots to prevent the
passage of light.
CHX
To evaluate the effect of CHX in the
self-adhesive cements, the prepared root
canals were randomly divided into 4
subgroups: Subgroup A, RelyX Unicem;
Subgroup B, 2% CHX + RelyX Unicem;
Subgroup C, RelyX U100; Subgroup
D, 2% CHX + RelyX U100. Prior to
32
May/June 2015
General Dentistry
Table 1. Luting system, adhesive strategies, and mode of cure used in each group
in the study.
Luting system, adhesive
Group strategies, and mode of cure Composition
1
Scotchbond Multi-Purpose
Activator: ethyl, alcohol, benzene sulfinic acid, sodium salt
Plus adhesive system,
Primer: water, hydroxyethyl methacrylate (HEMA), Vitrebond
etch-and-rinse, chemical cure copolymer
Catalyst: bisphenol A glycidyl methacrylate (Bis-GMA), HEMA,
benzoyl peroxide
Rely X ARC resin cement,
dual cure
Silane-treated ceramic, triethyleneglycoldimethacrylate
(TEGDMA), Bis-GMA, silane-treated silica, functionalized
dimethacrylate polymer
ED Primer, self-etching,
self-cure
Primer A: HEMA, N-methacryloyl 5-aminosalicylic acid (5-NMSA),
methacryloyloxydecyl dihydrogen phosphate (MDP), water,
accelerator
Primer B: HEMA, 5-NMSA, water, initiator, accelerator
Clearfil SE Bond adhesive
system, self-etching,
dual cure
Primer: HEMA, MDP, hydrophilic aliphatic dimethacrylate,
dicamphorquinone, water, accelerators, dyes
Bond: Bis-GMA, HEMA, MDP, hydrophobic aliphatic dimethacrylate, colloidal silica, dicamphorquinone, initiators, accelerators
Panavia F resin cement,
dual cure
Paste A: dimethacrylate, MDP, barium glass powder, sodium
fluoride, silica
Paste B: dimethacrylate, MDP, barium glass powder, sodium
fluoride, silica, benzoyl peroxide, amine, sodium aromatic sulfinate
Clearfil SE Bond adhesive
system, self-etching,
physical cure
Primer: HEMA, MDP, hydrophilic aliphatic dimethacrylate,
dicamphorquinone, water, accelerators, dyes.
Bond: Bis-GMA, HEMA, MDP, hydrophobic aliphatic dimethacrylate, colloidal silica, dicamphorquinone, initiators, accelerators
Panavia F resin cement,
dual cure
Paste A: dimethacrylate, MDP, barium glass powder, sodium
fluoride, silica
Paste B: dimethacrylate, MDP, barium glass powder, sodium
fluoride, silica, benzoyl peroxide, amine, sodium aromatic sulfinate
Scotchbond Multi-Purpose
Plus adhesive system,
etch-and-rinse, physical cure
Activator: ethyl, alcohol, benzene sulfinic acid, sodium salt
Primer: water, HEMA, Vitrebond copolymer
Catalyst: Bis-GMA, HEMA, benzoyl peroxide
Rely X ARC resin cement,
dual cure
Silane-treated ceramic, TEGDMA, Bis-GMA, silane-treated silica,
functionalized dimethacrylate polymer
5
RelyX U100 resin cement,
self-adhesive, dual cure
Glass powder, methacrylated phosphoric acid esters, TEGDMA,
silane-treated silica, sodium persulfate, glass powder, substituted
dimethacrylate, silane-treated silica, sodium p-toluene sulfinate,
calcium hydroxide
6
RelyX Unicem, resin cement,
self-adhesive, dual cure
Powder: glass powder, silica, calcium hydroxide, substitute
pyrimidine, peroxy compound, pigment, initiator
Liquid: methacrylated phosphoric ester, dimethacrylate,
stabilizer, initiator
2
3
4
cementing the root canals, Subgroups
B and D were irrigated with 2% CHX
digluconate solution for 1 minute; the
excess was dried with absorbent paper
points. The luting procedures of the
fiberglass posts with self-adhesive cements
were performed as described previously.
www.agd.org
Nanoleakage test
After cementation procedures were performed, the restored roots were stored in
relative humidity for 24 hours at 37°C.
Using an Isomet 1000 digital cutting
machine (Buehler), the roots were sectioned perpendicular to the long axis.
Table 2. Bonding procedures used in the study.
Group
Dentin pretreatment
Resin cement application
1 Etch-and-rinse Apply etch (37% phosphoric acid) for 15 seconds. Rinse with water
and dry with paper points. Apply primer. Dry with gentle airflow
for evaporation of solvent (5 seconds). Apply adhesive (Scotchbond
Multi-Purpose). After each application, remove excess with paper
points. Light cure for 10 seconds.
Dispense Rely X Arc cement onto mixing pad and mix for 30 seconds.
Apply mixed paste with aid of Centrix syringe and seat post in root
canal. Remove excess cement. Light cure for 40 seconds.
2 Self-etching
Clearfil SE Bond: Actively apply primer for 20 seconds. Dry with
gentle airflow for evaporation of solvent. Apply adhesive (Clearfil SE
Bond). Dry with gentle airflow for 3 seconds. After each application,
remove excess with paper points. Light cure for 10 seconds.
ED Primer: Mix 1 drop each of Primers ED-A and ED-B. Apply mixture
to root canal; leave in place for 60 seconds. Remove excess primer
with paper points. Dry with gentle airflow.
Mix Panavia F paste A and paste B for 20 seconds. Apply mixed paste
with aid of Centrix syringe and seat post in root canal. Remove excess
cement. Light cure for 40 seconds.
3 Self-etching
Actively apply primer for 20 seconds. Dry with gentle airflow for
evaporation of solvent. Apply adhesive (Clearfil SE Bond). Dry with
gentle airflow for 3 seconds. After each application, remove excess
with paper points. Light cure for 10 seconds.
Mix Panavia F paste A and paste B for 20 seconds. Apply mixed paste
with aid of Centrix syringe and seat post in root canal. Remove excess
cement. Light cure for 40 seconds.
4 Etch-and-rinse Apply etchant (37% phosphoric acid) for15 seconds. Rinse with water
and dry with paper points. Apply Scotchbond Multi-Purpose activator
and gently agitate for 5 seconds. Apply primer. Apply catalyzer. After
each application, remove excess with paper points.
Dispense Rely X ARC cement onto a mixing pad and mix for
30 seconds. Apply mixed paste with aid of Centrix syringe and seat
post in root canal. Remove excess cement. Light cure for 40 seconds.
5 Self-adhesive
No pretreatment.
Dispense Rely X U100 cement onto mixing pad and mix for 30
seconds. Apply mixed paste with aid of Centrix syringe and seat post
in root canal. Remove excess cement. Light cure for 40 seconds.
6 Self-adhesive
No pretreatment.
Rinse with water. Dry by blowing with air syringe and with paper
points. Activate capsule and mix Rely X Unicem cement in mixer for
15 seconds. Remove excess cement after seating of the restoration.
Light cure for 40 seconds.
The first slice (1 mm thick) of each root
was discarded. The samples were cleaned
with 10% liquid phosphoric acid for
10 seconds, washed, and submitted to
ultrasound for 10 minutes. Next, each
specimen was immersed in a 50% ammoniac silver nitrate solution for 24 hours in
dark conditions at 37°C. The specimens
were then thoroughly rinsed in distilled
water for 2 minutes and immersed in
a photodeveloping solution for 8 hours
(Kodak Developer D-76, Eastman Kodak
Company) under fluorescent light, in
order to reduce silver ions to metallic
silver grains along the bonded interface,
adhesive resin, and cement polymeric
structure. Next, the stained specimens
were embedded in a polystyrene resin and
wet-polished sequentially with aluminum
oxide papers (600, 1200, and 2000 grit)
and finished with a diamond paste of
decreasing grain using a metallographic
polisher (PL02, Arotec SA). After each
step of the polishing procedure, the specimens were immersed in distilled water
and placed in ultrasonic baths (Ultrasone
D 1440, Odontobras) for 10 minutes.
The specimens were dried with absorbent papers and immersed in a solution
of 50% phosphoric acid for 10 seconds,
followed by rinsing in distilled water.
For deproteinization, a 10% solution of
sodium hypochlorite was used for 10
minutes. The specimens were then rinsed,
dried at room temperature for 2 hours,
and dehydrated with ethanol (at increasing concentrations of 25%, 50%, 75%,
90%, and 100%), for 10 minutes each.
The specimens were carbon-coated (SCD050 Sputter Coater, Leica Microsystems)
and analyzed in a scanning electron
microscope (SEM) (JEOL Ltd.) at 15 kV.
The images of silver-infiltrated specimens
were taken in order to calculate the
marked area using the computer software
Image Tool 3.0 (University of Texas,
www.agd.org
Health Science Center at San Antonio).
The integrity of the interface in each third
was then expressed as the percentage of
the continuous (gap-free) interface. The
percentage of the continuous interface
along the entire cement-radicular dentin
interface was also calculated.
Statistical analysis
Data were analyzed using ANOVA followed by Tukey’s test at a 5% level of
significance (P = 0.05).
Statistical analysis of the data obtained
in the nanoleakage test was performed
according to a casual split-plot design,
in which the factors under study were
the cements, the plot, and the root third;
Tukey’s test was applied.
Results
Nanoleakage evaluation
ANOVA indicated statistically significant
differences between the different luting
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33
Dental Materials Nanoleakage of fiber posts luted with different adhesive strategies
Table 3. Mean nanoleakage percentage and standard deviation (SD) for the luting systems and the root thirds.
Groups
1 Etch-and-rinse
2 Self-etching
3 Self-etching
4 Etch-and-rinse
5 Self-adhesive
6 Self-adhesive
Coronal
Root thirds
17.56 (2.28) aA
17.52 (1.12) aA
23.64 (2.17) bA
21.85 (2.18) aA
13.32 (0.71) aA
23.26 (2.65) aA
Middle
15.49 (1.99) aA
24.09 (4.25) aA
23.02 (3.36) bA
20.88 (3.86) aA
15.79 (4.04) aA
21.07 (7.64) aA
Apical
12.23 (3.89)
22.65 (2.07)
37.11 (1.13)
20.42 (7.30)
16.43 (3.18)
20.43 (5.30) aA
aA
aA
aB
aA
aA
Data with same superscript letters (uppercase for rows, lowercase for columns) are not significantly different ( P < 0.05).
Groups: Group 1, Scotchbond Multi-Purpose Plus chemical cure + RelyX ARC; Group 2, Clearfil SE Bond + ED Prime dual cure + Panavia F;
Group 3, Clearfil SE Bond physical cure + Panavia F; Group 4, Scotchbond Multi-Purpose Plus physical cure + RelyX ARC; Group 5, RelyX U100; Group 6, RelyX Unicem.
systems and between interactions of luting
systems and root thirds. The results of
Tukey’s test are presented in Table 3.
Group 3 presented greater nanoleakage
in the apical third, with statistically significant differences between the middle
and cervical thirds (Fig. 1A). A statistically significant difference was also found
in the apical thirds of the other groups.
The resin tags formed inside the
dentinal tubule by the specimens in
Group 3 were short and/or not very
pronounced (Fig. 1B). A lower mean
nanoleakage percentage was achieved by
the Group 1 specimens in the apical third,
but it did not differ significantly from the
other remaining groups (Fig. 2A). It was
also possible to observe extensive resin tag
formation inside the dentinal tubules in
Group 1 specimens (Fig. 2B).
In the specimens of Groups 5 and 6,
the SEM images showed no formation of
a hybrid layer at the adhesive interface of
these cements. This was also true with
Subgroups B and D which were pretreated with CHX. All the specimens of
self-adhesive cement presented nanoleakage (Fig. 3 and 4).
Nanoleakage evaluation for CHX
ANOVA indicated statistically significant
differences between the self-adhesive
cements not pretreated with CHX and
the self-adhesive cements treated with
CHX. No difference was observed among
the root thirds of the CHX groups.
The results of Tukey’s test are presented
in Table 4.
Discussion
Fiber posts can be cemented using conventional dual-cure resin-based cements
34
May/June 2015
General Dentistry
Fig. 1. A. Scanning electron miscroscope (SEM) image showing a large quantity of nanoleakage in the adhesive
interface of a specimen in Group 3. B. SEM image showing that the hybrid layer is extensively infiltrated by silver.
Fig. 2. A. SEM image showing low nanoleakage in a specimen from Group 1. B. SEM image at 250X magnification.
in combination with etch-and-rinse
or self-etch adhesives, or by using the
recently formulated self-adhesive cements
that allow simultaneous bonding between
the root dentin and the post. Due to the
large variety of products and the intrinsic difficulties of bonding within the
endodontic space, the use of an adequate
luting strategy is particularly important as
it directly affects the quality of the toothluting interface.13,20
www.agd.org
When the nanoleakage patterns between
the root dentin and the luting system were
evaluated, a better quality, thicker hybrid
layer with long resin tags in the dentinal
tubules could be observed for Group 1 at
the apical thirds (Fig. 5). With the exception of Group 3, there were no statistically
significant differences for the other groups.
A 3-step etch-and-rinse adhesive system
increases the interfacial adaptation of dualcure luting cements because it increases
Table 4. Mean nanoleakage (%)
and standard deviation (SD) for the
self-adhesive cements pretreated
with chlorhexidine (CHX).
Group
Fig. 3. A. SEM image showing a very low silver infiltration by a specimen in Group 5 (magnification 50X).
B. SEM image at 500X magnification.
Mean % (SD)
Tukey’s
RelyX Unicem
with CHX
9.17 (2.47)
a
RelyX U100
with CHX
9.27 (3.16)
a
RelyX U100
without CHX
15.18 (2.96)
b
RelyX Unicem
without CHX
21.59 (5.00)
c
Data with same lowercase letters are not
significantly different ( P < 0.05).
Fig. 4. A. SEM image of a Group 6 specimen showing nanoleakage occurring throughout the adhesive
interface (magnification 50X). B. SEM image at 500X magnification.
Fig. 5. A. Image in secondary electron imaging (SEI) mode at the adhesive interface of a specimen from Group
1 (magnification 1000X). B. SEI image at 3500X magnification.
adhesive penetration into the dentinal
tubules, forming long resin tags in the
tubules that are opened by acid etching,
thereby improving the pattern of dentin
hybridization.21 However, during the
post space preparation, a thick smear
layer was created on the root canal walls
(mainly in the apical third) which, due
to the root’s anatomical configuration,
favors the accumulation of debris in the
apical region. In this sense, the dentin
pretreatment with the use of phosphoric
acid in the etch-and-rinse technique
may have been the determining factor
in the lower nanoleakage percentage at
the apical third in Group 1 compared
to Group 3 (P < 0.0001). It is possible
that the self-etch adhesive used in Group
3 (Clearfil SE Bond) was not acidic
enough to etch the dentin surface and
www.agd.org
dissolve the thick root dentin smear layer
accumulated in the apical region.
On the other hand, specimens of Group
2 (self-etching adhesive strategy) showed
values in the apical third similar to the
ones found in Group 1 (etch-and-rinse
adhesive strategy). Group 2 incorporated
the dual-cured Panavia F cement with the
self-etching Clearfil SE Bond and the selfetching and self-curing ED Primer. The
use of Clearfil SE Bond without the ED
Primer in Group 3 may have contributed
to poor infiltration of the resin cementdentin interface due to possible incompatibility with the dual-cured Panavia F
resin cement. After photoactivation of
Clearfil SE Bond, a nonpolymerized resin
layer (with a pH of 1.35) remained on
the top of the polymerized adhesive resin
layer due to an oxygen interaction.22,23
The acid resin monomers—caused by
oxygen inhibition in the nonpolymerized adhesive residual layer—react with
the tertiary amine of the resin cement.24
Moreover, these adhesives promote a
permeable hybrid layer, allowing water
diffusion from the dentin and forming water droplets along the adhesive
resin-cement interface, which may have
contributed to the significant interfacial
nanoleakage demonstrated in the apical
third of the specimens of Group 3.25 The
further application of the ED Primer in
Group 2 of this study probably helped
eliminate the inherent incompatibility
between the self-etch adhesive Clearfil
General Dentistry
May/June 2015
35
Dental Materials Nanoleakage of fiber posts luted with different adhesive strategies
and the dual-cured Panavia F resin
cement, via the t-isopropylic benzenic
sodium sulfinate co-initiator that is added
to ED Primer liquid B, which reacts with
the acidic resin monomers present in the
EB Primer liquid A along with the resin
cement itself to produce free radicals that
can enhance the polymerization reaction.26,27 The importance of ED Primer
on the polymerization effectiveness of
Panavia F was confirmed by Grande da
Cruz et al in 2012.28
Another aspect that justifies the use
of Panavia F with Clearfil SE Bond for
fiber post luting is the fact that the 2-step
self-etch adhesive Clearfil SE Bond used
in this study presents a high amount
of viscous hydrophobic monomers on
the bonding agent. This increases the
viscosity of this adhesive, which can then
reduce its diffusion, resulting in lower
microretention, decreasing the quality
of adhesive interlocking, and eventually
compromising the sealing ability of the
adhesive. The results in this study showing high values of nanoleakage for this
resin luting system in the apical third can
be explained by the difficulty in achieving direct irradiation by light in the deep
regions of root canals.29,30
Groups 5 and 6 (self-adhesive cements)
were comparable with Groups 1 and 4
(RelyX ARC in combination with etchand-rinse adhesive groups). Other
studies have related satisfactory results
using RelyX Unicem cement, which is
chemically identical to RelyX U100.20
The favorable adhesion to root canal
dentin may have occurred due to the fact
that both the RelyX U100 and RelyX
Unicem self-adhesive cements are highly
compatible with the substrate and can
optimize physical interactions, such as
micromechanical retention and chemical
bonding.31 RelyX Unicem has a chemical interaction with hydroxyapatite; this
interaction may be based on the chelation of the calcium ions by acid groups,
leading to chemical adhesion to the
hydroxyapatite in the tooth. The 10%
fluoride content in RelyX Unicem has led
to speculation that minor nanoleakage
could be related to the water repulsion
effect of the fluoride ions, which may help
to reduce residual water in the bonding
interface and thus improve its resistance
to hydrolytic degradation.32,33
36
May/June 2015
General Dentistry
The multifunctional, phosphoric acidmodified, methacrylate monomers of RelyX
U100 (pH <2) demineralize root dentin
as well as infiltrate the substrate and react
with the hydroxyapatite of hard tissues.34
The micromechanical retention associated
with the chemical adhesion to hydroxyapatite provides self-adhesiveness to the RelyX
U100 cement.35 This chemical interaction
produces water, which accelerates neutralization of phosphoric-acid methacrylate,
basic fillers, and hydroxyapatite.34 The
system likely gained water resistance, and,
although water and buffering of the smear
layer may have reduced demineralization
capacity, the effectiveness of the RelyX
U100 cement was not compromised.
The analysis of the results of the effect
of 2% CHX pretreatment on the adhesive
interface quality of self-adhesive resin
cements showed significantly lower nanoleakage on the tooth-luting interfaces that
were pretreated with CHX prior to luting
with self-adhesive systems. The decreased
nanoleakage results of the self-adhesive
cements results can be explained by the
increase in the dentin surface energy, and
the interaction between the dentin surface
and the resin cement is strongly dependent
upon the equilibrium of high surface
energy and high wettability.36,37
In addition, self-adhesive cements do not
require acid etching. Thus, when CHX is
applied to smear-covered dentin surfaces,
it can partially remove the smear layer and
even expose some underlying dentinal
tubules. CHX has cationic properties,
thereby enabling it to bind to phosphorated groups in apatite, and thus producing
a strong affinity for tooth surfaces.19,38
This study assessed the interfacial
nanoleakage of fiber posts after 24 hours
of water storage. The results showed that
the extension of silver nitrate deposition
along the bonded interface of fiber posts
was significantly influenced by the luting
system. However, the study findings do not
indicate with certainty that any 1 of the 3
investigated adhesive approaches is better
than the others. It is possible that a longer
storage time and/or thermal cycling in
future studies would give different results.
Nevertheless, according to the results
observed in this study, the self-etching
approach may offer less favorable adhesion
to root canal dentin in comparison with
etch-and-rinse or self-adhesive approaches.
www.agd.org
Based on these findings, clinicians
should be aware that, although in the
majority of clinical investigations fiber
posts are cemented using dual-cured resin
cements with etch-and-rinse adhesives,
the number of clinical steps in these
procedures might favor the occurrence of
errors.1,2,39-41 Scientists and manufacturers
have been continuously challenged to
simplify clinical procedures.14 The selfadhesive cements require no techniquesensitive steps and should therefore be
considered as an interesting alternative
for luting of intracanal posts because they
also present a satisfactory performance, as
indicated in the results of the laboratory
nanoleakage test in this study. Regarding
the effect of dentin pretreatment with
CHX, in addition to the inhibitory
effects of CHX on dentin proteases, the
application of CHX appears to promote
an adequate seal at the resin cementdentin interface.17,42
Conclusion
Within the limitations of this study,
it was possible to conclude that Group
3 (Clearfil SE Bond + Panavia F) group
showed higher nanoleakage patterns in
the apical third compared to the other
groups; the specimens of the self-adhesive
strategies groups (Groups 5 and 6) demonstrated similar results as compared to
the conventional etch-and-rinse adhesive
strategies; and in CHX-treated adhesive
interfaces of self-adhesive luting cements,
reduced uptake of silver particles
was observed.
Author information
Drs. Pontes, Araujo, Prieto, de Oliveira,
and Coppini are students in Restorative
Dentistry, Department of Restorative
Dentistry, Piracicaba Dental School, State
University of Campinas, Brazil, where Dr.
Paulillo is a titular professor. Dr. Pontes is
also an adjunct professor, Department of
Dentistry, State University of Amazonas,
Brazil. Dr. Araujo is also an assistant professor, Department of Dentistry, Faculty
of Sciences of Health, Federal University
of Jequitinhonha and Mucuri Valley,
Diamantina, Brazil. Dr. Dias is a titular
professor, Department of Statistical
Mathematics, Luiz de Queiroz Higher
School of Agriculture, University of Sao
Paulo, Piracicaba, Brazil.
References
1. Cagidiaco MC, Radovic I, Simonetti M, Tay F, Ferrari M.
Clinical performance of fiber post restorations in endodontically treated teeth: 2-year results. Int J Prosthodont. 2007;20(3):293-298.
2. Ferrari M, Cagidiaco MC, Goracci C, et al. Long-term
retrospective study of the clinical performance of fiber
posts. Am J Dent. 2007;20(5):287-291.
3. Torbjorner A, Karlsson S, Syverud M, Hensten-Pettersen A. Carbon fiber reinforced root canal posts. Mechanical and cytotoxic properties. Eur J Oral Sci. 1996;
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4. Stape TH, Menezes MS, Barreto BC, Aguiar FH, Martins
LR, Quagliatto PS. Influence of matrix metalloproteinase synthetic inhibitors on dentin microtensile bond
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6. Ferrari M, Mannocci F, Vichi A, Cagidiaco MC, Mjor IA.
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7.Schwartz RS, Fransman R. Adhesive dentistry and
endodontics: materials, clinical strategies and procedures for restoration of access cavities: a review.
J Endod. 2005;31(3):151-165.
8. Tay FR, Loushine RJ, Lambrechts P, Weller RN, Pashley DH. Geometric factors affecting dentin bonding
in root canals: a theoretical modeling approach.
J Endod. 2005;31(8):584-588.
9. Foxton RM, Nakajima M, Tagami J, Miura H. Bonding
of photo and dual-cure adhesives to root canal dentin.
Oper Dent. 2003;28(5):543-551.
10. Vichi A, Grandini S, Davidson CL, Ferrari M. An SEM
evaluation of several adhesive systems used for bonding fiber posts under clinical conditions. Dent Mater.
2002;18(7):495-502.
11. Asmussen E, Peutzfeldt A, Heitmann T. Stiffness, elastic
limit, and strength of newer types of endodontic posts.
J Dent. 1999;27(4):275-278.
12. Calixto LR, Bandeca MC, Clavijo V, Andrade MF, Vaz
LG, Campos EA. Effect of resin cement system and
root region on the push-out bond strength of a translucent fiber post. Oper Dent. 2012;37(1):80-86.
13. Mazzoni A, Marchesi G, Cadenaro M, et al. Push-out
stress for fibre posts luted using different adhesive
strategies. Eur J Oral Sci. 2009;117(4):447-453.
14. Radovic I, Monticelli F, Goracci C, Vulicevic ZR, Ferrari M. Self-adhesive resin cements: a literature review.
J Adhes Dent. 2008;10(4):251-258.
15. Saskalauskaite E, Tam LE, Mccomb D. Flexural strength,
elastic modulus, and pH profile of self-etch resin luting
cements. J Prosthodont. 2008;17(4):262-268.
16. Nishitani Y, Yoshiyama M, Wadgaonkar B, et al. Activation of gelatinolytic/collagenolytic activity in dentin by
self-etching adhesives. Eur J Oral Sci. 2006;114(2):
160-166.
17. Carrilho MR, Geraldeli S, Tay F, et al. In vivo preservation of the hybrid layer by chlorhexidine. J Dent Res.
2007;86(6):529-533.
18. Breschi L, Mazzoni A, Nato F, et al. Chlorhexidine stabilizes the adhesive interface: a 2-year in vitro study.
Dent Mater. 2010;26(4):320-325.
19. Hiraishi N, Yiu CK, King NM, Tay FR. Effect of 2%
chlorhexidine on dentin microtensile bond strengths
and nanoleakage of luting cements. J Dent. 2009;
37(6):440-448.
20. Silva RA, Coutinho M, Cardozo PI, Silva LA, Zorzatto
JR. Conventional dual-cure versus self-adhesive resin
cements in dentin bond integrity. J Appl Oral Sci.
2011;19(4):355-362.
21. Radovic I, Corciolani G, Magni E, et al. Light transmission through fiber post: the effect on adhesion, elastic
modulus and hardness of dual-cure resin cement. Dent
Mater. 2009;25(7):837-844.
22. Schittly E, Bouter D, Le Goff S, Degrange M, Attal JP.
Compatibility of five self-etching adhesive systems
with two resin luting cements. J Adhes Dent. 2010;
12(2):137-142.
23. Rueggeberg FA, Margeson DH. The effect of oxygen
inhibition on an unfilled/filled composite system.
J Dent Res. 1990;69(10):1652-1658.
24. Tay FR, Pashley DH, Yiu CK, Sanares AM, Wei SH. Factors contributing to the incompatibility between simplified-step adhesives and chemically-cured or
dual-cured composites. Part I. Single-step self-etching
adhesive. J Adhes Dent. 2003;5(1):27-40.
25. Carvalho RM, Pegoraro TA, Tay FR, Pegoraro LF, Silva
NR, Pashley DH. Adhesive permeability affects coupling of resin cements that utilise self-etching primers
to dentin. J Dent. 2004;32(1):55-65.
26. Kuraray America, Inc. ED Primer B MSDS USA [product
information]. Available at: kuraraydental.com/msds/
item/panavia-21-ed-primer-B-msds-usa. Accessed February 20, 2015.
27. Ikemura K, Endo T. Effect of adhesion of new polymerization initiator systems comprising 5-monosubstituted barbituric acids, sulfinate amides, and tert-butyl
peroxymaleic acid in dental adhesive resin. J Appl
Polym Sci. 1999;72(13):1655-1668.
28. Grande da Cruz FZ, Grande CZ, Roderjan DA, Galvao
Arrais CA, Buhrer Samra AP, Calixto AL. Effect of etchand-rinse and self-etching adhesive systems on hardness uniformity of resin cements after glass fiber post
cementation. Eur J Dent. 2012;6(3):248-254.
29. Van Landuyt KL, Snauwaert J, De Munck J, et al. Systematic review of the chemical composition of contemporary dental adhesives. Biomaterials. 2007;
28(26):3757-3785.
30. Prieto LT, Souza EJ Jr, Araujo CT, Lima AF, Dias CT, Paulillo LA. Knoop hardness and effectiveness of dualcured luting systems and flowable resin to bond
leucite-reinforced ceramic to enamel. J Prosthodont.
2013;22(1):54-58.
31. Goracci C, Cury AH, Cantoro A, Papacchini F, Tay FR,
Ferrari M. Microtensile bond strength and interfacial
properties of self-etching and self-adhesive resin cements used to lute composite onlays under different
seating forces. J Adhes Dent. 2006;8(5):327-335.
32. Gerth HU, Dammaschke T, Zuchner H, Schafer E.
Chemical analysis and bonding reaction of RelyX Unicem and Bifix composites—a comparative study. Dent
Mater. 2006;22(10):934-941.
33. Yuan Y, Shimada Y, Ichinose S, Tagami J. Hybridization
quality in cervical cementum and superficial dentin using current adhesives. Dent Mater. 2008;24(5):584-593.
34. Bitter K, Paris S, Pfuertner C, Neumann K, Kielbassa
AM. Morphological and bond strength evaluation of
different resin cements to root dentin. Eur J Oral Sci.
2009;117(3):326-333.
www.agd.org
35. 3M ESPE. RelyX U100 Self-Adhesive Universal Cement
[product information]. Available at: www.eugenol.
com/attachments/0007/9029/u100_sell_in.pdf. Accessed February 20, 2015.
36. Perdigao J, Denehy GE, Swift EJ Jr. Effects of chlorhexidine on dentin surfaces and shear bond strengths. Am
J Dent. 1994;7(2):81-84.
37. Di Hipolito V, Rodrigues FP, Piveta FB, Azevedo Lda C,
et al. Effectiveness of self-adhesive luting cements in
bonding to chlorhexidine-treated dentin. Dent Mater.
2012;28(5):495-501.
38. Fardal O, Turnbull RS. A review of the literature on use
of chlorhexidine in dentistry. J Am Dent Assoc. 1986;
112(6):863-869.
39. Monticelli F, Grandini S, Goracci C, Ferrari M. Clinical
behavior of translucent-fiber posts: a 2-year prospective study. Int J Prosthodont. 2003;16(6):593-596.
40. Grandini S, Goracci C, Tay FR, Grandini R, Ferrari M.
Clinical evaluation of the use of fiber posts and direct
resin restorations for endodontically treated teeth. Int
J Prosthodont. 2005;18(5):399-404.
41. Naumann M, Blankenstein F, Kiessling S, Dietrich T.
Risk factors for failure of glass fiber-reinforced composite post restorations: a prospective observational
clinical study. Eur J Oral Sci. 2005;113(6):519-524.
42. Loguercio AD, Stanislawczuk R, Polli LG, Costa JA,
Michel MD, Reis A. Influence of chlorhexidine digluconate concentration and application time on resindentin bond strength durability. Eur J Oral Sci.
2009;117(5):587-596.
Manufacturers
Angelus Industria de Produtos Odontologicos S/A,
Londrina, Brazil
55.43.2101.3200, www.angelus.ind.br
Arotec SA, Sao Paulo, Brazil
55.11.4613.8600, arotek.com.br
Buehler, Lake Bluff, IL
800.283.4537, www.buehler.com
DENTSPLY Maillefer, Tulsa, OK
800.924.7393, www.maillefer.com
DFL Industria e Comercio, Rio de Janeiro, Brazil
55.21.3528.6766, www.dfl.com.br
Eastman Kodak Company, Rochester, NY
800.698.3324, www.kodak.com
JEOL Ltd., Welwyn Garden City, England
44.170.7377.117, www.jeol.com
Kerr Corporation, Orange, CA
800.537.7123, www.kerrdental.com
Kuraray America, Inc., New York, NY
800.879.1676, www.kuraraydental.com
Leica Microsystems, Buffalo Grove, IL
800.248.0123, www.leica-microsystems.com
Miltex, Inc., York, PA
800.654.2873, www.miltex.com
Odontobras, Curitiba, Brazil
55.16.4141.2969, www.odontobras.com
3M ESPE, St. Paul, MN
888.364.3577, solutions.3m.com
General Dentistry
May/June 2015
37
Case Presentations Dental findings in a child with chronic renal failure secondary to cystinosis
Exercise No. 367 Dental
Materials Subject Code 017
The 15 questions for this exercise are based on the
article, Nanoleakage of fiber posts luted with different
adhesive strategies and the effect of chlorhexidine
on the interface of dentin and self-adhesive cements,
on pages 31-37. This exercise was developed by Kim
Capehart, DDS, MBA, PhD(c), in association with the
General Dentistry Self-Instruction committee.
1. All of the following are consistent
problems that affect the bonding of
glass fiber posts to root canal dentin
except one. Which is the exception?
A.adverse geometric factors
B. peculiar histological characteristics of
root dentin
C.presence of accessory canals
D.difficulty in achieving direct irradiation
by light in deep regions of the root canal
2. Hybrid layer formation is critical in the
________ of the post space.
A.entire length
B. coronal third
C.middle third
D.apical third
3. The pH range that occurs immediately
after mixing self-adhesive cements is
_________.
A.1.5-1.9
B.2.0-2.4
C.2.5-2.9
D.3.0-3.4
4. CHX has been shown to have (an)
_________ effect on the endogenous
collagenolytic activity in dentin.
A.no
B.unknown
C.inhibitory
D.unrestrictive
5. All of the following were inclusion
criteria of the bovine roots except one.
Which is the exception?
A.multiple canals
B. completely formed apices
C.no excessive curvature
D.roots with tight canals
Reading the article and successfully completing this exercise will enable you to:
•identify the characteristics of fiber posts and dentin using various adhesive
strategies;
•identify the effects of various luting systems and chlorhexidine (CHX) in
dentin; and
•recognize the advantages of the various luting systems used for luting
fiber posts.
6. After the storage of the roots,
the gutta percha was removed and
at least ___ mm of endodontic filling
was left at the apex of each canal.
A.1
B.3
C.5
D.7
11. The acid resin monomers in the
nonpolymerized adhesive residual layer
react with the _______ amine of the
resin cement.
A.primary
B.secondary
C.tertiary
D.quaternary
7. The glass fiber posts were cleaned
with _____ % alcohol for 1 minute
followed by drying.
A.60
B.70
C.80
D.90
12. RelyX Unicem has a chemical
interaction with hydroxyapatite that
may be based on the chelation
of the __________ ions.
A.magnesium
B.phosphorus
C.calcium
D.oxygen
8. The specimens were carbon-coated
and analyzed by a scanning electron
microscope at _____ kV.
A.10
B.15
C.20
D.25
9. Data were analyzed using ANOVA
followed by ______ test at a 5% level
of significance.
A.Fisher’s LSD
B. Student Newman-Keuls (SNK)
C.Cronbach’s alpha
D.Tukey’s
10. The resin tags formed inside the
dentinal tubules by Group 3 specimens
were short and/or not very pronounced.
A lower mean nanoleakage percentage
was achieved by the Group 1 specimens
in the apical third.
A.Both statements are true.
B. The first statement is true;
the second is false.
C.The first statement is false;
the second is true.
D.Both statements are false.
13. Cationic properties of _____________
enable the binding of phosphorated
groups in apatite, producing a strong
affinity for the tooth surface.
A.phosphoric acid
B.hydroxyapatite
C.CHX
D.modified methacrylate monomers
14. The group consisting of Clearfil SE
Bond combined with ________ showed
higher nanoleakage patterns in the
apical third compared to other groups.
A.RelyX Unicem
B. ED Primer
C.CHX
D.Panavia F
15. CHX-treated adhesive interfaces of selfadhesive luting cements reduced the
uptake of ____________ particles.
A.hydroxyapatite
B.calcium
C.magnesium
D.silver
Answer form is on the inside back cover. Answers for this exercise must be received by April 30, 2016.
38
May/June 2015
General Dentistry
www.agd.org
Computer Designed/Fabricated Crowns
Microcomputed tomography marginal fit
evaluation of computer-aided design/computeraided manufacturing crowns with different
methods of virtual model acquisition
Flavio Domingues das Neves, DDS, MS, PhD n Celio Jesus do Prado, DDS, MS, PhD n Marcel Santana Prudente, DDS, MS Thiago Almeida Prado Naves Carneiro, DDS, MS n Karla Zancope, DDS, MS n Leticia Resende Davi, DDS, MS, PhD Gustavo Mendonca, DDS, MS, PhD n Lyndon Cooper, DDS, MS, PhD n Carlos Jose Soares, DDS, MS, PhD
This in vitro study used microcomputed tomography to evaluate
the marginal fit of crowns fabricated using a chairside computeraided design/computer-aided manufacturing (CAD/CAM) system
with different methods of virtual model acquisition. Crowns were
fabricated to fit in a cast containing a single human premolar. Four
methods of virtual model acquisition were used: Group 1 (control),
digital impressioning of a typodont; Group 2, digital impressioning
of a powdered typodont; Group 3, digital impressioning of a regular
impression; and Group 4, digital impressioning of a master cast.
C
eramic crowns can be produced using
different techniques, including computer-aided design/computer-aided
manufacturing (CAD/CAM) procedures,
available in dental practices, laboratories,
and production centers.1 The major advantage of this technology when compared to
conventional fixed prostheses is the reduction of both chair and laboratory time.2
A new CAD/CAM material, Lava
Ultimate Restorative (3M ESPE), is a resin
nanoceramic block that reportedly achieves
superior esthetic results and can be used in
chairside CAD/CAM systems (E4D, E4D
Technologies LLC).3-5 These blocks are
made of nanoceramic particles embedded
in a highly cured resin matrix; therefore
glaze firing is not recommended, as it
would melt the restoration. This nanoceramic material only needs to be subjected
to a polishing process before fixation, thus
enabling intra- or extraoral adjustments.3
An important issue to consider regarding
the clinical success of an all-ceramic restoration is the marginal fit.6-8 There is currently
no consensus regarding a defined clinically
acceptable marginal fit. Some studies have
shown that a marginal fit ≤120 µm is
clinically acceptable, whereas others have
recommended ≤100 µm or ≤75 µm.9-14 The
survival of ceramic inlays is also fundamentally dependent on durable bonding.15
Statistically significant differences were found between the marginal
gap of Group 2 and the other groups ( P < 0.05); no differences were
found among Groups 1, 3, and 4. The results showed that crowns
fabricated using the chairside CAD/CAM system exhibited significantly
smaller vertical misfit when a thin layer of powder was applied over the
typodont before digital impressioning.
Received: April 10, 2014
Revised: October 17, 2014
Accepted: November 10, 2014
Stereomicroscopy, scanning electron
microscopy, optical microscope and
microcomputed tomography (µCT)
are methods used to evaluate marginal
fit.7,13,16-26 Stereomicroscope techniques
require a transverse section of the sample
to measure the marginal gap, but this procedure can cause sample deformations.13
Analyses involving a scanning electron
microscope can be inaccurate, considering
the overlap, depending on the positioning
of the sample.22 The µCT system can be
relatively expensive; however, it is a nondestructive method.24-27 This 3-dimensional
(3D) system also provides detailed highresolution imaging, allowing an internal
view of the sample.28,29
To date, there has been little research
on the marginal fit of resin nanoceramic
crowns captured using the E4D chairside
CAD/CAM system.5 In this study, µCT
was used to evaluate the marginal fit of
crowns. The null hypothesis of this study
was that different methods of virtual
model acquisition would not influence the
marginal fit of resin nanoceramic crowns.
Materials and methods
Sample preparation
A human mandibular left first premolar
and adjacent teeth were fastened to a
typodont model and prepared by an
www.agd.org
experienced operator for an all-ceramic
crown. This procedure was approved
by the Federal University of Uberlandia
Ethics Committee (381/06). A standard
set of diamond burs (1014, 3145, 3098,
and 3098F, KG Sorensen) was used. The
preparation was free of undercuts, the
angles were rounded, and the walls were
tapered 6 degrees to the occlusal surface.
The margins were prepared with shoulders
and rounded axiogingival line angles.30
Restoration fabrication
The 4 experimental groups were based
on different methods for acquiring the
virtual models. All groups used Lava
Ultimate Restorative and were designated
as Group 1 (control), digital impressioning of a typodont; Group 2, digital
impressioning of a typodont with a thin
layer of titanium dioxide powder; Group
3, digital impressioning of a regular
impression; and Group 4, digital impressioning of a master cast.
The same scanning technology (E4D
laser scanner, E4D Technologies LLC)
was used for the 4 groups. For the control
group (Group 1), 5 digital impressions
were made of the prepared tooth fastened
to a typodont. For Group 2, 5 digital
impressions of the prepared tooth were
made, but not before a thin layer of
General Dentistry
May/June 2015
39
Computer Designed/Fabricated Crowns µCT marginal fit evaluation of CAD/CAM crowns
powder (ES-CAD Spray, Henry Schein
Dental) was applied. For Group 3, 5 regular impressions with heavy and light vinyl
polysiloxane impression material (Imprint
3 Quick Step, 3M ESPE) were taken from
the prepared tooth. For Group 4, 5 regular
impressions with Imprint 3 Quick Step
were made to obtain 5 stone dies with type
V dental stone (Die-Keen Green, Heraeus
Kulzer). For all 4 groups, the same operator made all the impressions at room temperature and obtained all the stone dies.
The crowns were designed for all 4
groups using E4D DentaLogic software
(version 2.0, E4D Technologies LLC)
with luting space and an adhesive gap
set to 10 μm. Finally, an E4D mill (E4D
Technologies LLC) was used for CAM processing of the designed crowns. The same
experienced operator made all the crowns.
Measuring procedures
No adjustments were made to the ceramic
crowns before marginal fit measurements.
The prepared tooth was removed, and
each crown was fixed to the same tooth
using silicone material (Fit Checker, GC
America, Inc.). To acquire images for marginal fit measurements, all specimens were
scanned using µCT (SCANCO CT40,
SCANCO Medical AG). Imaging was
performed at 70 kVp and 112 μA with
a resolution of 1024 x 1024 pixels. Pixel
size and slice width were both 8 μm, and
the scan time was approximately 1 hour.
A total of 630 2-dimensional images were
acquired for each specimen. Transaxial
images of the crown and prepared tooth
were captured first.
Thirteen images from the sagittal set
and 13 images from the coronal set (Fig. 1
and 2) were selected to illustrate sample
extension in 2 different planes. The 13
selected images were evenly distributed
between the first and last images that
contained the cervical margin. For each
image, 2 measurements of horizontal
fit and 2 measurements of vertical fit
were performed at 400X magnification
using CTAn processing software (version
1.12.0.0, Skyscan, Bruker microCT). For
vertical fit, measurements were taken
from the external crown margin to the
most external point of the tooth (Fig. 3).
For horizontal fit, measurements were
taken from the most external point at
the prepared margin of the tooth to the
40
May/June 2015
General Dentistry
Fig. 1. Microcomputed tomography (µCT) sagittal
image of a crown fixed on a prepared tooth.
Fig. 2. µCT coronal image of a crown fixed on a
prepared tooth.
B
A
Fig. 3. Schematic showing vertical misfit measurements (A).
Fig. 4. Schematic showing horizontal misfit
measurements (B).
crown margin (Fig. 4). The marginal fit
was measured at 52 sites for each specimen, according to the method used by
Groten et al.20
the vertical misfit (µm) and standard
deviation (SD) for each group. The mean
vertical misfits (SD) were Group 1, 66.5
(29.97); Group 2, 34.9 (6.67); Group
3, 59.7 (17.45); and Group 4, 92.34
(21.51). Statistically significant differences
in vertical fit between Group 2 and the
other groups were detected (P = .042),
but no difference was detected among
Groups 1, 3, and 4, which exhibited low
vertical misfit values. Horizontal misfit
values (defined as underextended, equally
extended, or overextended) were also calculated for each group: Group 1, 83.1%;
Group 2, 93.7%; Group 3, 75.4%, and
Group 4, 84.6% (Chart 2).
Statistical analyses
Statistical analyses were performed with
Sigma Plot statistical software (version
12.0, Systat Software, Inc.). A 1-way
ANOVA test was performed to determine the significance among groups,
followed by the Tukey test (α = 0.05) for
post hoc comparisons. Vertical marginal
fits were grouped according to the following values from previous studies:
<75 µm, 75-100 µm, 100-120 µm, and
>120 µm.9-12,14,31 The maximum acceptable vertical misfit was set to 75 µm.32,33
In addition, horizontal misfit values were
placed into 3 categories: underextended,
equally extended, and overextended.31,33
Results
With the exception of Group 4, the majority of vertical misfit values for the crowns
were <75 µm (Table). Chart 1 shows
www.agd.org
Discussion
The null hypothesis—that a different
method of virtual model acquisition does
not affect the marginal fit of resin nanoceramic crowns—was rejected. Data from
this study revealed statistically significant
differences in marginal fit when resin
nanoceramic crowns were produced with
different methods.
Table. Vertical misfit for each group
Minimum vertical misfit
Group
1
Misfit range (%)
µm
%
<75 µm
0
13.5
63.5
75-100 µm 100-120 µm
13.8
6.2
>120 µm
Maximum vertical
misfit (µm)
16.5
272.9
2
0
21.2
83.8
8.6
3.8
3.8
284.6
3
0
18.8
70.4
10.8
3.8
15.0
280.6
4
0
11.5
47.3
70.8
9.6
32.3
599.0
Chart 1. Vertical misfit (µm) and standard deviation (SD) for each group.
120
Vertical misfit (µm)
100
80
60
40
20
0
Typodont
Group 1
Powdered Typodont
Group 2
Regular Impression
Group 3
Master Cast
Group 4
Chart 2. Percentage of underextended, equally extended,
or overextended crowns fitted to the prepared tooth.
100
Typodont—Group 1
Powdered Typodont—Group 2
Regular Impression—Group 3
Master Cast—Group 4
Percent (%)
80
60
40
20
0
Underextended
Equally extended
Results concerning vertical misfit
favored the digital impressioning of
Group 2. This may be due to the powder
applied to the surface eliminating any
reflection and shine that may have
Overextended
affected the scanner.34 Although the
results revealed a statistically significant
difference between Groups 1 and 2, the
E4D manufacturer recommends an intraoral digital impression without powder
www.agd.org
application.5 Digital impressioning of
the typodont with powder could result
in lower misfit values. The present study
suggests that the upper limit of acceptable
misfit should be 75 µm.
Results of the horizontal misfit comparisons favored the digital impression of
Group 3. This may be due to the way 3D
scanners convert the optical data to a 3D
model, based on the distance from the
scanner’s sensor tip to the object.34 The
margin surface of Group 3 was the nearest to the scanner sensor tip of all groups
tested. Restorations with significant
horizontal misfit can facilitate the retention of food and bacterial plaque.6 This
makes a patient’s hygiene more difficult
to maintain, leading to periodontal problems and possible caries that may reduce
restoration longevity. Nevertheless, a horizontal misfit could be reduced by adjusting the crown or tooth. This adjustment
is not possible with a vertical misfit.
Five different impressions were made
to generate 5 virtual models, eliminating
the effect of variation associated with
preparation. This revealed marginal fit
discrepancies that specifically resulted
from different digital impression methods. Previous in vitro studies have used
different numbers of specimens per
group.10,15,25,26,29,35 In the present study,
52 measurements were performed per
sample. While other studies have used
magnifications of 250X, the present study
analyzed at 400X magnification.8.11
The clinical cementation process could
damage the master die, thus increasing
the marginal discrepancy, and a crosssection may be necessary before the
measurements are taken.8,13,25,29 In the
current study, a silicone material was used
to temporarily fix each crown in the same
tooth, using digital pressing.
General Dentistry
May/June 2015
41
Computer Designed/Fabricated Crowns µCT marginal fit evaluation of CAD/CAM crowns
Long-term clinical data are required to
verify the relative efficacy and importance of
these techniques. Within the limitations of
this study, the crowns manufactured by the
E4D chairside CAD/CAM process exhibited significantly smaller vertical misfit when
a thin layer of powder was applied over
the typodont before digital impressioning.
Further studies should be performed using
different types of dental stone to understand their influence on vertical misfit.
Author information
Drs. das Neves, do Prado, and Davi
are associate professors, Department
of Occlusion, Fixed Prostheses and
Dental Materials, Federal University of
Uberlandia, Brazil, where Dr. Soares
is an associate professor, Department
of Operative Dentistry and Dental
Materials. Drs. Prudente and Carneiro
are doctoral students, Federal University
of Uberlandia, Brazil, where Dr. Zancope
is a postdoctoral research fellow. Drs.
Mendonca and Cooper are associate
professors, Department of Prosthodontics,
The University of North Carolina at
Chapel Hill, UNC School of Dentistry.
Disclaimer
The authors have no financial, economic,
commercial, and/or professional interests
related to topics presented in this article.
References
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preparation angles on the precision of zirconia crown
copings fabricated by CAD/CAM system. Dent Mater J.
2008;27(6):814-820.
2. Renne W, McGill ST, Forshee KV, DeFee MR, Mennito
AS. Predicting marginal fit of CAD/CAM crowns based
on the presence or absence of common preparation
errors. J Prosthet Dent. 2012;108(5):310-315.
3. Koller M, Arnetzl GV, Holly L, Arnetzl G. Lava ultimate
resin nano ceramic for CAD/ CAM: customization case
study. Int J Comput Dent. 2012;15(2):159-164.
4. 3M ESPE. LAVA Ultimate CAD/CAM Restorative [product information]. Available at: http://www.3m.com/
wps/portal/en_US/3M/Dental/Products/Lava-Ultimate/.
Accessed March 9, 2015.
5. E4D Technologies, LLC. Planmeca Planscan System
[product information]. Available at: http://e4d.com/
planscan-complete-system/. Accessed March 9, 2015
6. Sorensen JA. A rationale for comparison of plaqueretaining properties of crown systems. J Prosthet Dent.
1989;62(3):264-269.
7. Baig MR, Tan KB, Nicholls JI. Evaluation of the marginal fit of a zirconia ceramic computer-aided machined
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May/June 2015
General Dentistry
(CAM) crown system. J Prosthet Dent. 2010;104(4):
216-227.
8. Pak HS, Han JS, Lee JB, Kim SH, Yang JH. Influence of
porcelain veneering on the marginal fit of Digident
and Lava CAD/CAM zirconia ceramic crowns. J Adv
Prosthodont. 2010;2(2):33-38.
9. McLean JW, von Fraunhofer JA. The estimation of cement film thickness by an in vivo technique. Br Dent J.
1971;131(3):107-111.
10. Davis DR. Comparison of fit of two types of all-ceramic
crowns. J Prosthet Dent. 1988;59(1):12-16.
11. Holmes JR, Sulik WD, Holland GA, Bayne SC. Marginal
fit of castable ceramic crowns. J Prosthet Dent. 1992;
67(5):594-599.
12. Reich S, Gozdowski S, Trentzsch L, Frankenberger R,
Lohbauer U. Marginal fit of heat-pressed vs. CAD/CAM
processed all-ceramic onlays using a milling unit prototype. Oper Dent. 2008;33(6):644-650.
13. Keshvad A, Hooshmand T, Asefzadeh F, Khalilinejad F,
Alihemmati M, Van Noort R. Marginal gap, internal fit,
and fracture load of leucite-reinforced ceramic inlays
fabricated by CEREC inLab and hot-pressed techniques. J Prosthodont. 2011;20(7):535-540.
14. Hung SH, Hung KS, Eick JD, Chappell RP. Marginal fit
of porcelain-fused-to-metal and two types of ceramic
crown. J Prosthet Dent. 1990;63(1):26-31.
15. Frankenberger R, Lohbauer U, Taschner M, Petschelt A,
Nikolaenko SA. Adhesive luting revisited: influence of
adhesive, temporary cement, cavity cleaning, and curing mode on internal dentin bond strength. J Adhes
Dent. 2007;9(Suppl 2):269-273.
16. Lee KB, Park CW, Kim KH, Kwon TY. Marginal and internal fit of all-ceramic crowns fabricated with two
different CAD/CAM systems. Dent Mater J. 2008;
27(3):422-426.
17. Grenade C, Mainjot A, Vanheusden A. Fit of single
tooth zirconia copings: comparison between various
manufacturing processes. J Prosthet Dent. 2011;
105(4):249-255.
18. Yuksel E, Zaimoglu A. Influence of marginal fit and
cement types on microleakage of all-ceramic crown
systems. Braz Oral Res. 2011;25(3):261-266.
19. Vanlioglu BA, Evren B, Yildiz C, Uludamar A, Ozkan YK.
Internal and marginal adaptation of pressable and
computer-aided design/computer-assisted manufacture onlay restorations. Int J Prosthodont. 2012;25(3):
262-264.
20. Groten M, Axmann D, Probster L, Weber H. Determination of the minimum number of marginal gap measurements required for practical in-vitro testing.
J Prosthet Dent. 2000;83(1):40-49.
21. Oyague RC, Sanchez-Jorge MI, Sanchez Turrion A.
Evaluation of fit of zirconia posterior bridge structures constructed with different scanning methods
and preparation angles. Odontology. 2010;98(2):
170-172.
22. Trifkovic B, Budak I, Todorovic A, et al. Application of
replica technique and SEM in accuracy measurement of
ceramic crowns. Measure Sci Rev. 2012;12(3):90-97.
23. da Costa JB, Pelogia F, Hagedorn B, Ferracane JL. Evaluation of different methods of optical impression making on the marginal gap of onlays created with CEREC
3D. Oper Dent. 2010;35(3):324-329.
24. Pelekanos S, Koumanou M, Koutayas SO, Zinelis S, Eliades G. Micro-CT evaluation of the marginal fit of different In-Ceram alumina copings. Eur J Esthet Dent.
2009;4(3):278-292.
www.agd.org
25. Borba M, Cesar PF, Griggs JA, Della Bona A. Adaptation of all-ceramic fixed partial dentures. Dent Mater.
2011;27(11):1119-1126.
26. Krasanaki ME, Pelekanos S, Andreiotelli M, Koutayas
SO, Eliades G. X-ray microtomographic evaluation of
the influence of two preparation types on marginal fit
of CAD/CAM alumina copings: a pilot study. Int J
Prosthodont. 2012;25(2):170-172.
27.Rungruanganunt P, Kelly JR, Adams DJ. Two imaging
techniques for 3D quantification of pre-cementation
space for CAD/CAM crowns. J Dent. 2010;38(12):
995-1000.
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the marginal and internal gaps in Cerec3 partial ceramic crowns. J Dent. 2009;37(5):374-382.
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30. Goodacre CJ, Campagni WV, Aquilino SA. Tooth preparations for complete crowns: an art form based on scientific principles. J Prosthet Dent. 2001;85(4):363-376.
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Procera crowns. Int J Prosthodont. 1997;10(5):478-484.
32. Neves FD, Carneiro TAPN, Prado CJ, et al. Micrometric
precision of prosthetic dental crowns obtained by optical scanning and computer-aided designing/computeraided manufacturing system. J Biomed Opt. 2014;
19(8):088003.
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disilicate crowns fabricated by using chairside CAD/
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Manufacturers
Bruker MicroCT, Kontich, Belgium
32.3.877.5705, www.skyscan.be
E4D Technologies LLC, Richardson, TX
972.234.3880, e4d.com
GC America, Inc., Alsip, IL
800.323.7063, www.gcamerica.com
Henry Schein Dental, Melville NY
800.372.4346, www.henryschein.com
Heraeus Kulzer, South Bend, IN
800.435.1785, www.heraeus-dental-us.com
KG Sorensen, Cotia, Brazil
55.11.4777.1061, www.kgsorensen.com.br
SCANCO Medical AG, Bruttisellen, Switzerland
41.44.805.9800, www.scanco.ch
Systat Software, Inc., Chicago, IL
312.220.0060, www.systat.com
3M ESPE, St. Paul, MN
888.364.3577, solutions.3m.com
Dental Materials
The effect of using propylene glycol as a vehicle on
the microhardness of mineral trioxide aggregate
Amin Salem Milani, DDS, MSc n Alireza Banifatemeh, DDS n Saeed Rahimi, DDS, MSc n Mohammad Asghari Jafarabadi, PhD
While it has been proven that the handling properties of mineral trioxide
aggregate (MTA) are improved upon mixing it with propylene glycol
(PG), this study sought to evaluate how PG affects the microhardness of
MTA in terms of setting quality. MTA was mixed with different proportions of distilled water (DW) and PG to prepare 5 groups (n = 30). The
DW/PG percent proportions used in Groups 1-5 were 100/0, 80/20,
50/50, 20/80, and 0/100, respectively. The mixed MTA was condensed
into acrylic molds. Half of the samples of each group were evaluated on
Day 4, the other half on Day 28. The results indicated that PG reduces
M
ineral trioxide aggregate (MTA)
was introduced initially as a
root perforation repair material.1
Subsequent studies revealed other favorable properties of MTA.2-6 As a result of
these studies, MTA is now recommended
as a root-end filling material, pulp capping agent, repair material for tooth
resorption, coronal barrier, canal obturation material, and an apical barrier for
open apex teeth.2-6
A primary drawback of MTA is that it is
difficult to handle.7,8 Studies have shown
attempts to improve MTA handling by
incorporating additives or mixing it with
different vehicles.7,9-11 One of the mixing
agents used with MTA is propylene glycol
(PG), a clear, nearly odorless, viscous
alcoholic compound with hygroscopic
properties.12,13 PG has been used as an
FDA-cleared food additive and in the
composition of systemic medications,
including diazepam and phenytoin.13,14
The special consistency of PG improves
handling of the materials.15,16
In 1962, Laws showed that mixing PG
with calcium hydroxide (Ca(OH)2) facilitates its placement into the root canal.17
Other studies demonstrated the antibacterial activity of PG against common
endodontic pathogens and found that it
penetrates root dentin better than distilled
water (DW).18-20 These favorable properties prompted other researchers to mix
Ca(OH)2 with different amounts of PG to
improve handling and enhance antibacterial activity; the results revealed that PG
increases the dissociation rate of Ca(OH)2.21
the microhardness of MTA, thus adversely affecting its setting process.
Group 2 (80% DW/20% PG) best improved the handling of MTA
without a significant reduction in setting quality.
Received: September 13, 2013
Accepted: December 16, 2013
Key words: mineral trioxide aggregate,
microhardness, MTA, propylene glycol
Because PG is biodegradable, it induces
the most favorable sustained release of
calcium and hydroxyl ions compared with
other vehicles, including DW. In 2012,
Ximenes & Cardoso found that blending
Ca(OH)2 paste with PG resulted in the
greatest diffusion of calcium and hydroxyl
ions through the dentin and cementum.22
Studies have also demonstrated the
enhanced antibacterial activity of Ca(OH)2
mixed with PG against Enterococcus faecalis,
which may be attributed to the increased
release of hydroxyl ions.19,23 Conversely,
Safavi & Nakayama showed that higher
concentrations of PG reduce the dissociation of Ca(OH)2 while a small amount
of PG in water (20%-30%) increases the
release of calcium and hydroxyl ions.24
Some studies have attempted to mix
MTA with varying amounts of PG to
improve its handling and physical properties.9,12,13 A 2007 study by Holland
et al evaluated the periapical tissue
response in dogs after the root canal
was filled with an MTA/PG or MTA/
DW paste; the results showed that the
MTA/PG paste could be placed into
root canals more easily than the MTA/
DW mixture.9 The study also found that
mixing MTA and PG does not influence
the biocompatibility of MTA. In a 2010
bacterial leakage study, Brito-Junior et
al reported that PG increased the sealing
ability of MTA.12 More recent studies
have shown that while PG prolongs the
setting of MTA, it improves the material’s push-out strength, flowability, pH,
and calcium ion release.13,15 The authors
www.agd.org
of these studies recommended the ratio
of 80% DW/20% PG as a suitable
vehicle for MTA.
There have been concerns that mixing
MTA with PG and DW can have an
adverse effect on its setting reaction.25-27 As
noted earlier, PG has hygroscopic properties, and water is absolutely essential for
MTA setting. It is possible that adding PG
to MTA interferes with the hydration process and adversely affects the latter’s properties; in fact, the microhardness of MTA is
related directly to its hydration and setting
process.25-27 The present study sought to
evaluate how different amounts of PG
affected the surface microhardness of MTA.
Materials and methods
Specimen preparation
MTA was mixed with DW and PG in
different proportions to create 5 different
groups (n = 30). Group 1 samples used
100% DW, Group 2 samples combined
80% DW and 20% PG, Group 3 samples
combined 50% DW and 50% PG, Group
4 samples mixed 20% DW with 80%
PG, and Group 5 samples used 100%
PG. The DW/PG ratios were determined
by volume, and the powder/liquid ratio
was the same for all groups (1 g MTA
powder/0.4 ml liquid).
Using an amalgam carrier, the samples
were packed incrementally into acrylic resin
molds (5 mm diameter x 4 mm height).
The extruded material was removed with
a No. 11 scalpel to provide a flat MTA
surface flush with the end of the molds.
The samples were covered by an oasis
General Dentistry
May/June 2015
43
Dental Materials The effect of using propylene glycol as a vehicle on the microhardness of mineral trioxide aggregate
sponge soaked in synthetic tissue fluid.
Half of the samples in each group were
incubated at 37°C and 95% humidity for
4 days and the remainder for 28 days. After
incubation, the surface of each sample was
wet polished using minimal hand pressure
and various silicon carbide–based sandpapers (300, 600, 1200, and 2400 grit).
The polished samples were cleaned gently
with DW to remove surface debris; at that
point, the surfaces were dried immediately
using an oil-free air spray.
Microhardness test
The Vickers hardness test was performed
using a microhardness tester with a square
base, pyramid-shaped indenter. A load of
300 g was applied for 10 seconds; at that
point, the microhardness values (kgf/mm2)
appeared on the digital readout of the
tester. For each specimen, the microhardness was measured on 3 separate locations
(no closer than 1 mm to each other or to
the sample periphery). The mean microhardness value was calculated and recorded.
Statistical analysis
The data were statistically analyzed
using SPSS software (Version 16, IBM
Corporation). Due to the heterogeneity
of variances (Levene test; P < 0.05), the
Welch robust test was used to compare
the mean hardness values among groups,
followed by the Games-Howell post hoc
test for pairwise comparison. Within each
group, a paired samples t test was used to
assess the different microhardness values
at Day 4 and Day 28. Values of P < 0.05
were considered significant.
Results
Group 5 was excluded from this study, as
the 100% PG prevented the MTA from
setting, making it impossible to measure
microhardness. The mean microhardness (kgf/mm2) values for the other
experimental groups are summarized
in the Table. The results of the Welch
robust test revealed significant differences among 4 groups at both Day 4
and Day 28 (P = 0.000). In addition, the
Games-Howell post hoc test showed that
all pairwise comparisons between groups
were significant (P < 0.05). The microhardness in Group 1 (100% DW) was
significantly higher than in other groups
(P < 0.05), and there was a corresponding
44
May/June 2015
General Dentistry
Table. Mean and standard deviation (SD) of Vickers surface microhardness
(kgf/mm2) in experimental groups.
Group
1
2
3
4
(100% DW) (80% DW/20% PG) (50% DW/50% PG) (20% DW/80% PG)
P value
Day 4
11.6 (3.5)
5.5 (1.5)
4.2 (0.9)
2.8 (0.6)
<0.001
Day 28
28.6 (10.7)
7.8 (2.6)
4.8 (1.6)
2.0 (0.6)
<0.001
P value
<0.001
0.019
0.252
0.006
Abbreviations: DW, distilled water; PG, propylene glycol.
Note: The P values in the right column are related to the difference of hardness among different groups at each time
point; however, the P values in the 3rd row are related to the differences in hardness of each group at 2 time points. For
example, 0.019 in the 3rd row means that the hardness of MTA with 80% DW/20% PG is greater at day 28 than day 4.
significant decrease in microhardness as
the proportion of PG to DW increased
(P < 0.05). The microhardness at Day 28
was significantly higher for Groups 1 and 2
(P < 0.05). By contrast, the microhardness
in Group 4 was significantly lower at Day
28 compared to Day 4 (P < 0.05). Group
3 samples showed no difference in microhardness between 4 and 28 days (P > 0.05).
Discussion
Mixing MTA powder with PG alone or
with a PG/DW mixture alters its consistency and improves handling.9,13,15 This
study sought to evaluate the effect of PG
on the microhardness of MTA as a criterion for the setting quality. Microhardness
is not a fundamental material property;
rather, it represents an arbitrary quantity
that is used to provide a relative idea of
other physical properties, such as yield
strength, tensile strength, and modulus of
elasticity; in addition, it is used as an indicator of MTA setting.26,28,29 The results of
the present study showed that adding PG
reduced MTA microhardness.
Adequate hydration is a factor that has a
direct effect on MTA’s setting reaction.25,30,31
The literature has shown that any environmental factor that affects the hydration of
MTA has the potential to change its physical properties.27,32 Therefore, the decrease
in microhardness that resulted from the
addition of PG may be explained by the
reduced percentage of DW in the liquid.
The hygroscopic property of PG means
it is likely to absorb more water from the
mixed MTA and further reduce the amount
of DW available for hydration. Duarte et
www.agd.org
al evaluated the effect of different DW/
PG ratios on pH and calcium ion release as
an indicator of MTA’s hydration process.13
Adding PG increased the pH and calcium
ion release during the initial setting phase;
however, both decreased consistently over
time and, after 24 hours, there was no
significant difference compared to samples
treated with 100% DW. Duarte et al concluded that adding PG reduced the amount
of water in the mixture without affecting
the hydration process.13 This conclusion
appears to contrast with the findings of the
present study. The authors of the present
study propose that evaluating pH and calcium ion release is not suitable as a single
criterion for the setting quality of MTA.
Alterations of other MTA properties (such
as microhardness) should also be considered as another indicator of the setting
process. An animal study found that MTA
pastes prepared with either DW or PG had
similar biocompatibility.9 Therefore, the
authors of the present study conclude that
although PG may have a negative effect on
the setting process, the effect is not so great
as to influence its biocompatibility.
Another finding in this study was
the increasing surface microhardness of
MTA with DW over time, corroborating the findings reported in previous
studies.27,33 This increased hardness value
indicates that MTA is likely to continue
to set and gain hardness over time.
However, in the present study, adding
PG to DW reduced this trend, in that the
hardness did not increase over time in
Group 3 (P > 0.05), and the hardness in
the Group 4 samples actually decreased
by Day 28. The mechanism for decreased
microhardness is unclear, and further
investigation is warranted. It seems that
20% PG combined with 80% DW had
the least adverse effect on this increasing
hardness trend over time compared to
higher PG concentrations.
Present data show that acidity, reduced
humidity, greater condensation pressure,
and contact with fetal bovine serum or
blood during setting have an adverse effect
on the setting process and reduce MTA
microhardness.25,26,33-35 Different mechanisms have been proposed for these findings. Kim et al suggested that the proteins
in fetal bovine serum interfere with the
setting reaction of MTA and reduce hardness.35 In addition, it has been hypothesized
that the scarcity of needle-like crystals when
MTA is set in contact with blood could
have a role in reduced microhardness.34,36
The exact mechanism of how PG affects
MTA microhardness is unclear. Future
studies might consider using scanning
electron microscopic analysis and energy
dispersive X-ray spectroscopy to characterize the surface of MTA mixed with PG and
thus elucidate the underlying mechanism.
A previous study showed that PG
increases the setting time of MTA.13
Other studies are underway to control this
adverse effect of PG on the setting time of
MTA by incorporating accelerants; however, additional study is needed to determine the effects these PG accelerants will
have on the different properties of MTA.
Conclusion
Based on the results of this study, it was
concluded that PG reduces the surface
microhardness of MTA and is likely
to have an adverse effect on its setting
process. A mixture of 80% DW and
20% PG is recommended to improve
MTA handling.
Author information
Dr. Salem Milani is an assistant professor
of Endodontics, Dental and Periodontal
Research Center, Tabriz University
of Medical Sciences, Iran, where Dr.
Banifatemeh is a general dental practitioner, Dr. Rahimi is a professor of
Endodontics, Department of Endodontics,
and Dr. Asghari Jafarabadi is an associate
professor of Biostatistics, Department of
Statistics and Epidemiology.
Acknowledgments
This article is a report resulting from
a DDS thesis registered at the Tabriz
University of Medical Sciences, Iran. The
authors wish to thank the Dental and
Periodontal Research Center at the Tabriz
University of Medical Sciences for their
financial support of this project.
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4. Milani AS, Rahimi S, Borna Z, Jafarabadi MA, Bahari
M, Deljavan AS. Fracture resistance of immature teeth
filled with mineral trioxide aggregate or calciumenriched mixture cement: an ex vivo study. Dent Res J
(Isfahan). 2012;9(3):299-304.
5. Vosoughhosseini S, Lotfi M, Shahmoradi K, et al. Microleakage comparison of glass-ionomer and white
mineral trioxide aggregate used as a coronal barrier in
nonvital bleaching. Med Oral Patol Oral Cir Bucal.
2011;16(7):e1017-e1021.
6. Parirokh M, Torabinejad M. Mineral trioxide aggregate:
a comprehensive literature review, III: clinical applications, drawbacks, and mechanism of action. J Endod.
2010;36(4):400-413.
7. Ber BS, Hatton JF, Stewart GP. Chemical modification
of ProRoot MTA to improve handling characteristics
and decrease setting time. J Endod. 2007;33(10):
1231-1234.
8. Milani AS, Shakouie S, Borna Z, Sighari Deljavan A, Asghari Jafarabadi M, Pournaghi Azar F. Evaluating the
effect of resection on the sealing ability of MTA and
CEM cement. Iran Endod J. 2012;7(3):134-138.
9. Holland R, Mazuqueli L, de Souza V, Murata SS, Dezan
Junior E, Suzuki P. Influence of the type of vehicle and
limit of obturation on apical and periapical tissue response in dogs’ teeth after root canal filling with mineral trioxide aggregate. J Endod. 2007;33(6):693-697.
10. AlAnezi AZ, Zhu Q, Wang YH, Safavi KE, Jiang J. Effect
of selected accelerants on setting time and biocompatibility of mineral trioxide aggregate (MTA). Oral
Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;
111(1):122-127.
11. Jafarnia B, Jiang J, He J, Wang YH, Safavi KE, Zhu Q.
Evaluation of cytotoxicity of MTA employing various
additives. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod. 2009;107(5):739-744.
12. Brito-Junior M, Viana FA, Pereira RD, et al. Sealing
ability of MTA-Angelus with propyleneglycol in furcal
perforations. Acta Odontol Latinoam. 2010;23(2):124128.
13. Duarte MA, Alves de Aguiar K, Zeferino MA, et al.
Evaluation of the propylene glycol association on
some physical and chemical properties of mineral trioxide aggregate. Int Endod J. 2012;45(6):565-570.
14. Ishiwata H, Nishijima M, Fukasawa Y. Estimation of
inorganic food additive (nitrite, nitrate and sulfur
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dioxide), antioxidant (BHA and BHT), processing
agent (propylene glycol) and sweetener (sodium saccharin) concentrations in foods and their daily intake
based on official inspection results in Japan in fiscal
year 1998. Shokuhin Eiseigaku Zasshi. 2003;44(2):
132-143.
15. Salem Milani A, Froughreyhani M, Charchi Aghdam S,
Pournaghiazar F, Asghari Jafarabadi M. Mixing with
propylene glycol enhances the bond strength of mineral trioxide aggregate to dentin. J Endod. 2013;39(11):
1452-1455.
16. Pacios MG, de la Casa ML, de los Angeles Bulacio M,
Lopez ME. Calcium hydroxide’s association with different vehicles: In vitro action on some dentinal components. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod. 2003;96(1):96-101.
17. Laws AJ. Calcium hydroxide as a possible root filling
material. N Z Dent J. 1962;58:199-215.
18. Bhat KS, Walkevar S. Evaluation of bactericidal property of propylene glycol for its possible use in endodontics. J Health Sci (Arogya). 1975;1:54-59.
19. Vaghela DJ, Kandaswamy D, Venkateshbabu N, Jamini
N, Ganesh A. Disinfection of dentinal tubules with two
different formulations of calcium hydroxide as compared to 2% chlorhexidine: as intracanal medicaments
against Enterococcus faecalis and Candida albicans:
an in vitro study. J Conserv Dent. 2011;14(2):182-186.
20. Cruz EV, Kota K, Huque J, Iwaku M, Hoshino E. Penetration of propylene glycol into dentine. Int Endod J.
2002;35(4):330-336.
21. Simon ST, Bhat KS, Francis R. Effect of four vehicles on
the pH of calcium hydroxide and the release of calcium ion. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod. 1995;80(4):459-464.
22. Ximenes M, Cardoso M. Assessment of diffusion of
hydroxyl and calcium ions of root canal filling materials in primary teeth. Pediatr Dent. 2012;34(2):122126.
23. Silveira CF, Cunha RS, Fontana CE, et al. Assessment of
the antibacterial activity of calcium hydroxide combined with chlorhexidine paste and other intracanal
medications against bacterial pathogens. Eur J Dent.
2011;5(1):1-7.
24. Safavi K, Nakayama TA. Influence of mixing vehicle on
dissociation of calcium hydroxide in solution. J Endod.
2000;26(11):649-651.
25. Nekoofar MH, Adusei G, Sheykhrezae MS, Hayes SJ,
Bryant ST, Dummer PM. The effect of condensation
pressure on selected physical properties of mineral trioxide aggregate. Int Endod J. 2007;40(6):453-461.
26. Namazikhah MS, Nekoofar MH, Sheykhrezae MS, et al.
The effect of pH on surface hardness and microstructure of mineral trioxide aggregate. Int Endod J. 2008;
41(2):108-116.
27. Sato EY, Svec T, Whitten B, Sedgley CM. Effects of bone
graft materials on the microhardness of mineral trioxide aggregate. J Endod. 2012;38(5):700-703.
28. Bentz DP. Cement hydration: building bridges and
dams at the microstructure level. Mater Structures.
2007;40(4):397-404.
29. Camilleri J. Hydration mechanisms of mineral trioxide
aggregate. Int Endod J. 2007;40(6):462-470.
30. Camilleri J, Montesin FE, Brady K, Sweeney R, Curtis
RV, Ford TR. The constitution of mineral trioxide aggregate. Dent Mater. 2005;21(4):297-303.
31. Santos AD, Moraes JC, Araujo EB, Yukimitu K, Valerio
Filho WV. Physico-chemical properties of MTA and a
novel experimental cement. Int Endod J. 2005;38(7):
443-447.
General Dentistry
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45
Dental Materials The effect of using propylene glycol as a vehicle on the microhardness of mineral trioxide aggregate
32. Shie MY, Huang TH, Kao CT, Huang CH, Ding SJ. The
effect of a physiologic solution pH on properties of
white mineral trioxide aggregate. J Endod. 2009;35(1):
98-101.
33. Kayahan MB, Nekoofar MH, Kazandag M, et al. Effect
of acid-etching procedure on selected physical properties of mineral trioxide aggregate. Int Endod J. 2009;
42(11):1004-1014.
34. Nekoofar MH, Oloomi K, Sheykhrezae MS, Tabor R,
Stone DF, Dummer PM. An evaluation of the effect of
blood and human serum on the surface microhardness
and surface microstructure of mineral trioxide aggregate. Int Endod J. 2010;43(10):849-858.
35. Kim Y, Kim S, Shin YS, Jung IY, Lee SJ. Failure of setting
of mineral trioxide aggregate in the presence of fetal
bovine serum and its prevention. J Endod. 2012;
38(4):536-540.
36. Salem Milani A, Rahimi S, Froughreyhani M, Vahid
Pakdel M. Effect of blood contamination on marginal
adaptation and surface microstructure of mineral trioxide aggregate: a SEM study. J Dent Res Dent Clin
Dent Prospects. 2013;7(3):156-162.
Manufacturer
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•Low-shrinkage composites:
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Tooth Whitening/Bleaching
Clinical performance of topical sodium
fluoride when supplementing carbamide
peroxide at-home bleaching gel
Daphne Camara Barcellos, DDS, MS, PhD n Graziela Ribeiro Batista, DDS, MS, PhD n Melissa Aline da Silva, DDS, MS Patricia Rondon Pleffken, DDS, MS, PhD n Marcia Carneiro Valera, DDS, MS, PhD
This clinical study evaluated the use of 0.11% topical sodium
fluoride (SF) desensitizing agent to treat tooth sensitivity during
a nightguard tooth whitening procedure. Thirty-two subjects
bleached their teeth with 10% carbamide peroxide (CP) gel
using an at-home bleaching technique with custom trays. During
bleaching treatment, subjects were divided into 2 groups (n = 16).
The subjects in Group 1 received a topical gel containing 0.11% SF;
the subjects in Group 2 received a placebo gel (PG). Each subject
was instructed to place the gel in his/her bleaching tray for 30 min
every day following bleaching treatment.
A
t-home tooth bleaching has been
greatly successful in dentistry. The
current agents used for bleaching
procedures are hydrogen peroxide or
carbamide peroxide (CP) in a variety of
concentrations.1 Tooth sensitivity is the
most common side effect associated with athome bleaching techniques. Clinical studies
of at-home bleaching treatments report
tooth sensitivity in 9%-100% of subjects.1,2
One of several etiological factors associated
with this complication is the low pH of
bleaching materials, which may produce
an acid-etch effect on dentin, consequently
removing minerals from the teeth.3 Other
factors in tooth sensitivity due to at-home
bleaching are the low levels of water content
within the bleaching materials and the
anhydrous materials used to dry the teeth.4
To decrease tooth sensitivity, the best
solution during at-home tooth bleaching is
to reduce either the frequency or duration
of bleaching applications.2 Also, the use of
topical fluorides or desensitizing pastes after
the bleaching session may reduce tooth sensitivity.5 Topical fluoride advantages include
being noninvasive, cost-effective, and easy
to apply, and it can be used either in inoffice or at-home techniques, depending on
the concentration of the solution.5
Most investigators have studied the use
of fluorides and other desensitizing agents
(such as potassium nitrate) in order to
effectively manage tooth sensitivity.1,2,6 The
Results showed the use of SF did not affect the whitening efficacy
of the 10% CP gel. Subjects who received the PG had significantly
higher tooth sensitivity when compared with subjects who received
SF (P < 0.00). The use of daily 0.11% SF after 10% CP bleaching gel
reduced tooth sensitivity during the bleaching treatment.
Received: August 19, 2013
Revised: December 9, 2013
Accepted: January 13, 2014
Key words: dental bleaching, carbamide peroxide, fluoride, tooth sensitivity
purpose of this clinical study is to evaluate
the use of topical fluoride on tooth sensitivity during a nightguard tooth whitening
procedure. The null hypothesis tested was
that the use of topical fluoride would not
affect tooth sensitivity during at-home
tooth bleaching.
Materials and methods
Initial shades
All subjects were evaluated for initial (baseline) shades with 3 calibrated examiners
(85% inter-rater reliability). Shades were
assessed using a shade guide (Vita Lumin
Vacuum, VITA Zahnfabrik) to record the
shades of the anterior teeth from the left to
the right canines.
This study was submitted to and
approved by the Ethical Committee in
Research of Sao Jose dos Campos School
of Dentistry, Sao Paulo State University,
Brazil (Protocol No. 039/2009-PH/CEP).
All subjects read and signed informed
consent forms.
Bleaching product
The home bleaching was accomplished
with a 10% CP gel (Bioformula Farmacia
de Manipulacao) that was manufactured
specifically for this study. In this formulation, the bleaching agent did not contain
desensitizing agents.
Subject selection
Thirty-two volunteer subjects (19 women
and 13 men) with a mean age of 24.8 years
participated in this study. Inclusion criteria
were teeth that were minimally A2-shaded
and good general health. Exclusion criteria
were restorations in anterior teeth, tooth
sensitivity, pregnancy/breastfeeding,
smoking, active caries, previous bleaching
treatments, and/or subjects who were <17
years of age.6
Bleaching trays
Alginate impressions (Jeltrate, DENTSPLY
International) of both dental arches of
each subject were taken to obtain stone
casts, which were then cut into horseshoe
shapes. Custom-fabricated bleaching trays
of ethyl vinyl acetate (FGM Produtos
Odontologicos) were formed for each
subject using a vacuum machine (Bio-Art
Equipamentos Odontologicos Ltda). The
bleaching trays did not have reservoirs
and were trimmed 1 mm above the
gingival margin without contacting the
gingival tissue.
All subjects received a syringe with
10% carbamide peroxide gel and were
instructed on how to load the bleaching
Bleaching procedure
The subjects received a complete oral
prophylaxis using rubber cups with
pumice then rinsing with water/air spray
for 30 seconds.
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General Dentistry
May/June 2015
47
Tooth Whitening/Bleaching Clinical performance of topical sodium fluoride when supplementing at-home bleaching gel
Table 1. Conversion of Vita Classical Shade
Guide tabs to numeric values.
Tab
Value
Tab
Value
Tab
Value
Tab
Value
B1
1
A2
5
A3
9
B4
13
Groups
A1
2
C1
6
D3
10
C3
14
Mean score (SD) of tooth sensitivity
P value
1 (SF)
0.84 (0.62)
<0.00*
1.39 (0.28)
<0.00*
B2
3
C2
7
B3
11
A4
15
2 (PG)
D2
4
D4
8
A3.5
12
C4
16
*Indicates statistical significance. Abbreviation: SF, sodium fluoride; PG, placebo gel.
Tooth sensitivity
After applying the SF or PG, the subjects
were instructed to record (on a visual scale
from 0 to 10) the degree of sensitivity
perceived during the whitening treatments:
Grade 0, absence of sensitivity; Grades 1-3,
slight sensitivity not necessitating suspension of treatment; Grades 4-6, moderate
sensitivity that forced suspension of treatment for 1 day; Grades 7-9, severe sensitivity that led to suspension of treatment for
more than 1 day; Grade 10, intolerable
sensitivity that led to complete suspension
of treatment.7,8 The subjects scored their
sensitivities every day after applying either
the desensitizing agent or the placebo. The
degree of sensitivity was calculated as the
mean of the treatment days.
Final shades
The bleaching outcomes were evaluated
with the Vita Lumin Vacuum shade guide
30 days after the onset of treatment using
May/June 2015
General Dentistry
Chart. Representation of tooth sensitivity (mean score)
reported during the bleaching treatment period.
2.5
Group 1 (Sodium fluoride)
Group 2 (Placebo)
2.0
Scale (mean score)
trays. The subjects received verbal and
written instructions regarding the bleaching procedure. All subjects employed
the bleaching product by filling both
the maxillary and mandibular trays for
14 consecutive nights in an 8 hour regimen. However, if a subject experienced
tooth sensitivity, he or she had the option
to discontinue the treatment at any time.
During the bleaching treatment, subjects were divided into 2 groups (n = 16).
Group 1 subjects received a gel containing
an 0.11% sodium fluoride (SF) desensitizing agent (Bioformula Farmacia de
Manipulacao); Group 2 subjects received a
placebo gel (PG) (Bioformula Farmacia de
Manipulacao). Each subject was instructed
to apply the gel in his/her bleaching tray
for 10 minutes every day following the
bleaching treatment.
48
Table 2. Mean score and standard deviation (SD) of tooth
sensitivity and results of the Wilcoxon signed-rank test.
1.5
1.0
0.5
0
12 345 678 91011121314
Days
the same 3 calibrated examiners from
the earlier visual evaluation. The shade
changes were obtained by Vita shade tabs
ranging from 1 (B1) to 16 (C4) (Table 1).7
Statistical analysis
The data collected from each treatment
group for changes in tooth sensitivity were
submitted to a Wilcoxon signed-rank test.
The data collected regarding the changes
in tooth shades were submitted to a statistical t test with a 5% level of significance.
Results
Tooth sensitivity
All 32 participants completed the study.
The data (mean score and standard deviations) collected regarding the changes in
tooth sensitivity are presented in Table 2.
A significant statistical difference in tooth
sensitivity was detected when Group 1
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and Group 2 were compared (P < 0.00).
Group 2 (placebo gel) demonstrated
statistically higher tooth sensitivity than
Group 1 (SF gel). The Chart describes the
comparison of tooth sensitivity during
the 14 days of bleaching treatment for
Groups 1 and 2.
Tooth shade
Table 3 presents the data collected for
changes in tooth shade. It was noted that
the 10% CP bleaching gel did significantly
whiten teeth.
Discussion
The first null hypothesis was rejected,
because there was a significant reduction
in tooth sensitivity for subjects in Group 1
compared to Group 2. SF is a compound
that—when in contact with mineralized
tooth structures—apparently causes
Conclusion
Table 3. Means and standard deviations (SDs) of subjective evaluation of tooth
shades and results of the statistical t test.
Group
Mean (SD) initial shade
Mean (SD) final shade
t value
P value
1 (SF)
5.48 (3.60)
2.87 (1.82)
6.35
<0.00*
2 (PG)
5.10 (2.95)
2.73 (1.58)
6.92
<0.00*
*Indicates statistical significance. Abbreviations: SF, sodium fluoride; PG, placebo gel.
reductions in the diameters of the dentinal
tubules by precipitating calcium fluoride
crystals.5 The speculated mode of action is
the formation of a calcified barrier blocking the tubule openings, consequently
decreasing tooth sensitivity.5 The results
of this present study were consistent with
the findings of Tam, Alonso de la Pena &
Balboa Cabrita, and Haywood et al, who
observed decreases of tooth sensitivity
when desensitizing agents such as fluoride
were used after at-home bleaching treatments with 10% CP bleaching gel.2,8,9
This study also corroborated the findings
of Armenio et al, who observed that using
1.23% SF for 4 minutes a day after bleaching with 16% CP reduced the intensity of
tooth sensitivity.10
The Chart depicts a significant reduction in tooth sensitivity for Group 1 on
Day 3. Calcium fluoride is an unstable
compound, providing a short period of
desensitizing effect, indicating the necessity
of regular daily applications after at-home
tooth bleaching to reduce tooth sensitivity.5
The typical duration of daily exposure to
fluorides (mouthrinses, dentifrices, pastes,
and gels) in contact with teeth is a few
minutes at most. In this study, the duration of daily exposure to SF after a bleaching treatment was 10 minutes. Therefore,
at least 10 minutes are necessary to achieve
satisfactory tooth desensitization after an
at-home bleaching treatment with SF.
Some studies have shown that bleaching
agents can cause changes in the surface
morphology of enamel, including such
negative effects as demineralization, erosion, wear, roughness, mineral content
loss, and reduction in enamel microhardness.11-16 Additionally, cleaning one’s teeth
with toothbrushing and/or using abrasive
toothpastes after a bleaching treatment
can enhance the phenomena of erosion
and wear.17 Therefore, toothbrushing
immediately following the use of topical
fluoride after a bleaching treatment should
be avoided, in order to prevent erosion
of the enamel surface.14,15 Also, the use of
daily SF therapy increases enamel hardness and may reverse the demineralizing
effect of the bleaching agent on the enamel
surface, potentially preventing the loss of
mineral content.6,16-20
For changes in tooth shade, this study
demonstrated that 10% CP bleaching gel
did significantly whiten teeth for Groups 1
and 2 (P < 0.00). Both treatment groups
in this study produced equivalent color
changes, and these results suggested that
topical fluoride therapy after at-home
tooth bleaching did not significantly affect
the bleaching efficacy within the parameters of this study. These results are in
agreement with other studies, which found
that various desensitizing agents (such as
fluoride) did not affect the efficacy of the
bleaching treatment.2,8
The current trend of incorporating
desensitizing agents in the bleaching agent
has shown promising results in reducing
tooth sensitivity and enamel remineralization without affecting the efficiency of the
bleaching. A major advantage of this new
technique is the reduced time required, as
there is no need to apply the agent before
or after a bleaching procedure, reducing
the risk of noncooperation by the patient.
This study indicated that the 10-minute
application of 0.11% SF gel as a desensitizing agent could be very helpful in
decreasing tooth sensitivity; it also did not
significantly affect the bleaching efficacy of
the 10% CP bleaching gel. Reducing tooth
sensitivity improves patient comfort during
bleaching procedures. Further research
should be conducted to determine whether
the 0.11% SF gel would exhibit this same
effect when different concentrations of CP
and/or hydrogen peroxide are used.
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The application of 0.11% topical SF gel
after a 10% CP bleaching gel treatment
reduced tooth sensitivity during a 2 week
at-home bleaching treatment.
Author information
Drs. Barcellos, Batista, da Silva, and
Pleffken received their PhDs from the
Sao Jose dos Campos School of Dentistry,
Universidade Estadual Paulista, Brazil,
where Dr. Valera is an associate professor,
Restorative Dentistry Department.
References
1. Matis BA, Cochran MA, Eckert GJ, Matis JI. In vivo
study of two carbamide peroxide gels with different
desensitizing agents. Oper Dent. 2007;32(6):549-555.
2. Tam L. Effect of potassium nitrate and fluoride on
carbamide peroxide bleaching. Quintessence Int.
2001;32(10):766-770.
3. Price RB, Sedarous M, Hiltz GS. The pH of tooth-whitening products. J Can Dent Assoc. 2000;66(8):421426.
4. Yarborough DK. The safety and efficacy of tooth
bleaching: a review of the literature 1988-1990.
Compend Contin Educ Dent. 1991;12(3):191-196.
5. Wichgers TG, Emert RL. Dentine hypersensitivity. Gen
Dent. 1996;44(3):225-230; quiz 231-232.
6. Tay LY, Kose C, Loguercio AD, Reis A. Assessing the effect of a desensitizing agent used before in-office
tooth bleaching. J Am Dent Assoc. 2009;140(10):
1245-1251.
7. Bernardon JK, Sartori N, Ballarin A, Perdigao J, Lopes
GC, Baratieri LN. Clinical performance of vital bleaching techniques. Oper Dent. 2010;35(1):3-10.
8. Alonso de la Pena V, Balboa Cabrita O. Comparison of
the clinical efficacy and safety of carbamide peroxide
and hydrogen peroxide in at-home bleaching gels.
Quintessence Int. 2006;37(7):551-556.
9. Haywood VB, Caughman WF, Franier KB, Myers ML. Tray
delivery of potassium nitrate-fluoride to reduce bleaching sensitivity. Quintessence Int. 2001;32(2):105-109.
10. Armenio RV, Fitarelli F, Armenio MF, Demarco FF, Reis
A, Loguercio AD. The effect of fluoride gel use on
bleaching sensitivity: a double-blind randomized controlled clinical trial. J Am Dent Assoc. 2008;139(5):
592-597; quiz 626-627.
11. Spalding M, Taveira LA, de Assis GF. Scanning electron
microscopy study of dental enamel surface exposed to
35% hydrogen peroxide: alone, with saliva, and with
10% carbamide peroxide. J Esthet Restor Dent. 2003;
15(3):154-164.
12. Efeoglu N, Wood DJ, Efeoglu C. Thirty-five percent
carbamide peroxide application causes in vitro demineralization of enamel. Dent Mater. 2007;23(7):900904.
13. Sulieman M, Addy M, Macdonald E, Rees JS. A safety
study in vitro for the effects of an in-office bleaching
system on the integrity of enamel and dentine. J Dent.
2004;32(7):581-590.
14. Worschech CC, Rodrigues JA, Martins LR, Ambrosano
GM. In vitro evaluation of human dental enamel surface roughness bleached with 35% carbamide peroxide and submitted to abrasive dentifrice brushing.
Pesqui Odontol Bras. 2003;17(4):342-348.
General Dentistry
May/June 2015
49
Tooth Whitening/Bleaching Clinical performance of topical sodium fluoride when supplementing at-home bleaching gel
15. Imfeld T. Prevention of progression of dental erosion
by professional and individual prophylactic measures.
Eur J Oral Sci. 1996;104:215-220.
16. Attin T, Kocabiyik M, Buchalla W, Hannig C, Becker K.
Susceptibility of enamel surfaces to demineralization
after application of fluoridated carbamide peroxide
gels. Caries Res. 2003;37(2):93-99.
17. Chen HP, Chang CH, Liu JK, Chuang SF, Yang JY. Effect
of fluoride containing bleaching agents on enamel
surface properties. J Dent. 2008;36(9):718-725.
18. Borges AB, Samezima LY, Fonseca LP, Yui KC, Borges
AL, Torres CR. Influence of potentially remineralizing
agents on bleached enamel microhardness. Oper Dent.
2009;34(5):593-597.
19. Navarra CO, Reda B, Diolosa M, et al. The effects of
two 10% carbamide peroxide nightguard bleaching
agents, with and without desensitizer, on enamel and
sensitivity: an in vivo study. Int J Dent Hyg. 2014;12(2):
115-120.
20. Borges AB, Dantas RL, Caneppele TM, Borges AL, Rocha Gomes Torres C. Effect of remineralizing agents on
the bleaching efficacy of gels. Gen Dent. 2013;61(7):
67-71.
Manufacturers
Bio-Art Equipamentos Odontologicos Ltda,
Sao Carlos, Brazil
55.16.3371.6502, www.bioart.com.br
Bioformula Farmacia de Manipulacao,
Sao Jose dos Campos, Brazil
11.2065.6936, www.bioformula.com.br
DENTSPLY International, York, PA
800.877.0020, www.denstply.com
FGM Produtos Odontologicos, Joinville, Brazil
55.47.3441.6100, www.fgm.ind.br
VITA Zahnfabrik, Bad Sackingen, Germany
49.7761.56.20, www.vita-zahnfabrik.com
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May/June 2015
General Dentistry
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Dental Materials
Physical properties of a new sonically placed
composite resin restorative material
Emily T. Ibarra, DMD, MS n Wen Lien, DDS, MS n Jeffery Casey, DDS n Sara A. Dixon, DDS, MS n Kraig S. Vandewalle, DDS, MS
A new nanohybrid composite activated by sonic energy has been recently introduced as a single-step, bulk-fill restorative material. The purpose of this study was to compare the physical properties of this new
composite to various other composite restorative materials marketed
for posterior or bulk-fill placement. The following physical properties
were examined: depth of cure, volumetric shrinkage, flexural strength,
flexural modulus, fracture toughness, and percent porosity. A mean
and standard deviation were determined per group. One-way ANOVA
and Tukey’s post hoc tests were performed per property (α = 0.05).
Percent porosity was evaluated with a Kruskal-Wallis/Mann-Whitney
C
omposite resin was first introduced
in the 1960’s as an alternative to
acrylic resins for esthetic dental
restorations.1 Initially these materials
performed poorly, but increased popularity and demand for esthetic restorations
have driven continued improvement in
strength, wear resistance, handling, and
esthetics.2 For many years, composite
resin restorations have been considered
an acceptable treatment choice for anterior applications. Recent advances in
composite resin mechanical properties
and improved adhesive systems have
broadened the application of these materials to include the restoration of posterior teeth.3 However, it is still generally
accepted that posterior composite resin
restorations have limitations and that
there is no one ideal material available.4
A volumetric shrinkage occurs when a
composite resin material is cured.1 The
shrinkage is the result of conversion of
monomer molecules into a more dense
polymer network, which leads to bulk
contraction.5 In vivo studies have demonstrated the percentage of marginal gaps
in a composite resin restoration may vary
between 14% and 54% depending on
the materials and technique.6 The resulting marginal gap may provide a site for
recurrent caries; this is cited as the most
common cause of failure for composite
resins.7 In spite of significant advances in
composite resin composition, there has
not been an equivalent decrease in microleakage and gap formation.8
test (α = 0.005). Significant differences were found between groups
( P < 0.001) per test type. Compared to the other composite restorative
materials, the new nanohybrid composite showed low shrinkage and
percent porosity, moderate fracture toughness and flexural modulus,
and high flexural strength. However, it also demonstrated a relatively
reduced depth of cure compared to the other composites.
Received: May 24, 2013
Revised: October 18, 2013
Accepted: November 14, 2013
Another concern regarding composite
resin is the depth of cure during placement. When composite resin is applied
as a single bulk layer, there may be a low
degree of polymerization at the depth of
deeper cavity preparations due to attenuation of the light.1 An insufficient degree of
curing affects the composite resin’s chemical properties and may lead to the elution of possible irritant, allergic, or toxic
components from the material.9 Uncured
composite resin at the base of a restoration
may also cause microleakage with resulting
pulpal sensitivity, staining, and recurrent
caries.10 Additionally, incomplete curing is
associated with a reduction in the mechanical properties of the material.11
Historically, composite resin restorations have been advocated for use in areas
of minimal stress.10 However, increased
demand has led to a greater use of these
restorations on posterior teeth, where
considerable mechanical challenges
occur during function.12 To withstand
these stresses, the modification of filler
particle size and morphology has resulted
in improved mechanical properties.13
Heavily filled composite resins have
improved mechanical strength, fracture
properties, and wear resistance.4 However,
as the maximum filler volume is about
70%, overloading can result in poor
handling characteristics and technical
difficulties, such as decreased wettability.14 Filler content not only directly
determines the mechanical properties
of composite resin but also allows for a
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reduction in monomer content; improves
handling properties; and influences wear
resistance, translucency, opalescence,
radiopacity, intrinsic surface roughness,
and polishability.15
Another clinical aspect of concern
regarding composite resins is their handling characteristics. The ability of a
composite material to flow may play a
major role in the ultimate success of a
restoration.16 However, in many Class II
cavity preparations, it is difficult to obtain
proper contour and adequate proximal
contacts because the composite resin is not
packable.17 The desire for composite resins
with certain flow characteristics has been
addressed by the introduction of packable
and flowable composite resins. Packable
composite resins were first introduced
as an alternative to amalgam.10 They are
characterized by a high filler load and a
filler distribution that gives them a different consistency when compared with
traditional composite resins. Flowable
composite resins contain lower filler
concentrations and are characterized by a
lower elastic modulus and viscosity.18 For
the average clinician, the ideal composite
resin material would be viscous enough to
facilitate placement but flowable enough
for adequate marginal adaptation.19
SonicFill (Kerr Corporation) is a new
composite resin material that the manufacturer claims to address many of the
problems listed above. SonicFill is a single-step, bulk-fill composite resin system
that, according to the manufacturer, has
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Dental Materials Physical properties of a new sonically placed composite resin restorative material
Table 1. Composite resin components.
Composite
Type
Manufacturer Resin
Filler
SonicFill
Nanohybrid
Kerr
Corporation
3-trimethoxysilylpropyl methacrylate,
ethoxylated bisphenol-Adimethacrylate (Bis-EMA),
bisphenol-A-bis-(2-hydroxy3-methacryloxypropyl) ether,
triethyleneglycoldimethacrylate
(TEGDMA)
Silicon dioxide, barium glass
83
QuiXX
Hybrid
DENTSPLY
Caulk
Urethane dimethacrylate (UDMA),
TEGDMA
Silanated strontium aluminum
sodium fluoride phosphate
silicate glass
86
66
Unreported
Tetric EvoCeram Nanohybrid
Bulk Fill
Ivoclar
Vivadent,
Inc.
UDMA, bisphenol A
glycidylmethacrylate (Bis-GMA)
Barium glass,
ytterbium trifluoride,
mixed oxide prepolymer
82-84
64
550 nm mean
particle size;
range: 40 nm
to 3000 nm
Filtek Z250
Microhybrid
3M ESPE
TEGDMA, UDMA, Bis-EMA
Zirconia/silica particles
82
60
0.01-3.5 µm
Average: 0.6 µm
Filtek LS
Silorane
3M ESPE
Silorane
Quartz, ytterbium trifluoride
76
55
0.04-1.7 μm
“…ultraefficient curing characteristics
that ensure an optimal, full 5 mm depth
of cure in 20 seconds.”20 Sonic activation purportedly lowers the viscosity of
the material to allow for easy adaptation
to cavity walls. The manufacturer also
claims that, after placement, the composite resin returns to a “non-slumping state”
that allows for easy contouring.20
To fully understand SonicFill’s place
in a clinician’s daily practice, one must
first understand the different types of
composite resins available on the market.
Most dental composite resin materials are
composed of a polymeric matrix (typically
dimethacrylate), reinforcing fillers (typically radiopaque glass), a silane coupling
agent to bind the filler to the matrix, and
chemicals that promote or modulate the
polymerization reaction. Because of the
major influence of fillers on the physical
properties of dental composite resins,
their classification is based on the type
and particle size of fillers.4 Currently, the
most traditional methacrylate composite
resins for restorative purposes are the
hybrid and microfill types.21 Microfill
composite resins are formulated with
fillers having an average particle size
ranging from 0.01 to 0.05 µm and prepolymerized particles approximately 50
µm in size. These composite resins were
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General Dentistry
designed to overcome the problems of
poor esthetic properties. However, the
mechanical properties of microfills are
typically too low for applications in areas
of high functional stress.4 Microhybrids
offer intermediate esthetic properties but
excellent mechanical properties by the
incorporation of fillers with different
average particle sizes, 15-20 µm and 0.010.05 µm.21 A recent development with
methacrylate-based composites has been
nanocomposites, which contain nanoscale
particles and nanohybrids, which contain
a mixture of nanoscale particles and larger
particles.4 The manufacturers of these
nanocomposites claim that they combine
the mechanical strength of hybrids and
the superior polishabiliy of microfills,
in addition to high wear resistance and
reduced polymerization shrinkage.22 In
general, it is difficult to discern dramatic
differences between nanohybrids and the
more traditional microhybrids because
many manufacturers have simply modified their microhybrid composition to
include more nanoparticles or even prepolymerized resin fillers.21 The physical
properties of the flexural strength and
modulus of nanohybrids and microhybrids tend to be similar.4 Filtek Z250
(3M ESPE) is a traditional microhybrid
composite resin that has demonstrated
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Weight % Volume % Filler size
Unreported Unreported
excellent mechanical properties in multiple laboratory studies and is often used
as a standard to compare various new
restorative materials.22
In addition to the traditional composite resin restorative materials, a unique
composite resin, Filtek LS (3M ESPE),
has recently been marketed for posterior
restorations. Instead of the conventional
methacrylate-derived monomer, Filtek LS
utilizes a ring-opening silorane monomer.
It demonstrates mechanical properties
similar to those of methacrylate composite resins but has the distinct advantage
of reduced polymerization shrinkage.
The expansion of the ring before polymerization has been shown to decrease the
polymerization shrinkage to <1.5%.22
Historically, the maximum incremental
thickness with composite resin placement has been 2 mm. However, restoring
deeper preparations with 2 mm increments is time consuming and relatively
technique sensitive. Manufacturers have
introduced new “bulk-filled” restorative
composites, which reportedly can be
cured in increments of ≥4 mm. Examples
include SonicFill, Tetric EvoCeram Bulk
Fill (Ivoclar Vivadent, Inc.), and QuiXX
(DENTSPLY Caulk). The compositions
of the new bulk-fill composites appear to
be similar to those of the nanohybrid and
microhybrid restorative composites currently available. However, a greater depth
of cure may be obtained by improving
the translucency or by the incorporation of additional photoinitiators.23 Very
little information has been published
on the physical properties of this new
class of materials.
The purpose of this study was to compare the physical properties of the new
sonically placed composite and other composite resin restorative materials marketed
for posterior placement or bulk fill. The
null hypothesis tested was that there would
be no significant difference in physical
properties among the various composite
resin restorative materials.
Materials and methods
The resin composites used in this study
were SonicFill (shade A2), QuiXX (universal shade), Tetric EvoCeram Bulk Fill
(shade IVA), FiltekZ250 (shade A2), and
Filtek LS (shade A2) (Table 1). The following properties were evaluated: depth of
cure, volumetric polymerization shrinkage,
flexural strength, flexural modulus, fracture toughness, and internal porosity.
Depth of cure
To determine depth of cure, the composite resins were tested using the scraping
technique (ISO 4049).24 Five specimens
per group were created. A 4 mm diameter
by 14 mm long stainless steel split mold
(Sabri Dental Enterprises, Inc.) was placed
on a plastic strip-covered glass slide on a
standard white background. The composite resin was injected into the mold and
a plastic strip was placed. The composite
resin was condensed with a glass slide
to displace excess resin. The glass slide
was removed and the specimens were
immediately polymerized with a curing
light (Bluephase G2, Ivoclar Vivadent,
Inc.) for 20 seconds. Each specimen was
polymerized at a distance of 0 mm utilizing a clamp to hold the curing light. The
light emission from the Bluephase G2 was
analyzed with a spectrophotometer (Blue
Light Analytics, Inc.) and a laser power
meter (FieldMax II, Coherent, Inc.). The
curing light was connected to a power
cord to provide continuous, consistent
operation. The emitted light was analyzed
during a 20-second curing cycle and
the following data were collected: mean
irradiance, 1132 mW/cm2; total energy
density, 22.8 J/cm2; energy density in
the 360-420 nm spectrum, 4.2 J/cm2;
and energy density in the 420-540 nm
spectrum, 18.6 J/cm2. The uncured resin
was then scraped with a plastic instrument
starting from the deepest point on the
underside of the mold until polymerized
resin was reached. The composite resin was
removed from the mold and the length of
the remaining polymerized material was
measured with an electronic digital caliper
(GA182, Grobet USA) and divided by 2,
according to the ISO standard.24
Volumetric polymerization
shrinkage
To determine polymerization shrinkage,
the AcuVol method by Bisco, Inc. was
used.25 Ten specimens per group were
created. The composite resins were placed
on a pedestal in a video imaging device
(AcuVol, Bisco, Inc.). The specimens
were imaged from the side at a distance
of 10 cm. The video camera digitized and
analyzed the images with the provided
image processing software. The specimens
were light-cured for 40 seconds using the
curing light unit as before. Polymerization
shrinkage was recorded continuously for
5 minutes after the light initiation.
Flexural strength and
flexural modulus
To determine flexural strength and
flexural modulus, a 3-point bending test
was used. Ten specimens per group were
created. A 2 x 2 x 25 mm stainless steel
mold (Sabri Dental Enterprises, Inc.)
was placed on a plastic strip-covered
glass slide. The specimens were created
by injecting the restorative material into
the mold until completely filled. The
top surface of the mold was covered with
a second plastic strip and glass slide as
before. One side of the specimen was
exposed to a light polymerization unit in
5 separate overlapping increments of 20
seconds each. Next, the mold was turned,
and the opposite side of the specimen was
exposed to the light in a similar manner.
The specimens were then removed from
the mold and stored in distilled water
at an intraoral temperature of 37°C for
24 hours. Each specimen was placed
on a 3-point bending test device which
was constructed with a 20 mm span
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length between the supporting rods.
The central load was applied with a head
diameter of 2 mm, and a crosshead speed
of 0.25 mm/min using a universal testing
machine (MTS Systems Corporation).
The flexural strength was calculated
using the equation:
sFS = 3Fl2
2bd
Where F is the loading force at the
fracture point, l is the length of the
support span (20 mm), b is the width,
and d is the depth. Measurements were
made using the electronic digital caliper. Flexural modulus was determined
from the slope of the linear region of
the load-deflection curve using analytical software (TestWorks 4, MTS
Systems Corporation).
Fracture toughness
Fracture toughness was determined by a
single-edge notched beam method. Ten
specimens per group were created. To
prepare each specimen, a knife-edged split
2 x 2 x 25 mm stainless steel mold (Sabri
Dental Enterprises, Inc.) was placed on a
plastic strip-covered glass slide as before.
The specimens were made by inserting the
restorative material into the mold until
completely filled. Then the top surface
of the mold was covered with a second
plastic strip and glass slide as before. One
side of the specimen was then exposed to
a light polymerization unit for 20 seconds
each in 5 separate overlapping increments.
Next, the mold was turned over, and the
opposite side of the specimen was exposed
to the light in a similar manner. The
specimens were stored as before, and after
24 hours, the notched specimens were
fractured in the universal testing machine
similar to flexural strength testing, but at
a crosshead speed of 1.0 mm/min, with
the notch on the tensile side. The loaddeflection (F = load vs u = deflection)
curves were recorded; the height, h, and
width, w, of the specimens were measured
with the inside jaws of an electronic digital caliper as before and the notch depth,
a, with a measuring stereomicroscope
(Nikon SMZ-1B, Nikon USA) at 10X
magnification. Fracture toughness (K IC )
was calculated from measurements with
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Dental Materials Physical properties of a new sonically placed composite resin restorative material
Table 2. Physical properties of the restorative materials.
Physical property mean (standard deviation)
Restorative material
Depth of
cure (mm)
Volumetric polymerization
Flexural
shrinkage (%)
strength (MPa)
SonicFill (A2 shade)
3.67 (0.02) b
1.88 (0.15) b
QuiXX (universal shade)
6.31 (0.02) e
Tetric EvoCeram Bulk Fill (IVA shade)
4.08 (0.03)
Filtek LS (A2 shade)
2.06 (0.02) a
1.21 (0.08) a
113.89 (18.57) a
9.17 (0.39) a
Filtek Z250 (A2 shade)
3.79 (0.02)
2.13 (0.08)
139.41 (16.35)
10.86 (0.46)
d
c
Flexural
modulus (GPa)
Fracture toughness
(MPa m1/2)
Percent
porosity
136.81 (16.29) b
10.32 (0.38) b
0.56 (0.03) ab
0.02 (0.04) a
2.00 (0.08) bc
111.86 (16.84) a
13.34 (0.84) c
0.61 (0.05) b
1.42 (1.17) c
2.31 (0.11)
101.41 (5.86)
8.55 (0.55)
0.52 (0.05)
a
0.40 (0.76) b
0.52 (0.05) a
0.44 (0.57) b
0.62 (0.08)
0.13 (0.09) b
d
c
a
b
a
b
b
Groups with the same lowercase letter per column are not significantly different.
the single-edge notched-bend specimens
using the equation:
K IC =
3(a/w)½[1.99– a/w (1–a/w)
(2.15–3.93a/w+2.7(a/w)2]FS
2(1+2a/w)(1–a/w)3/2hw3/2
Where S is the span distance (20 mm)
between supports.
Internal porosity
A novel microtomographic technique
was used to evaluate internal porosity.
Ten specimens per group were created. To
prepare each specimen, a 2 mm long and
8 mm diameter plastic mold (Sabri Dental
Enterprises, Inc.) was placed on a plastic
strip-covered glass slide. The restorative
materials were injected into the mold until
completely filled. Then, the top surface of
the mold was covered with a second plastic
strip and glass slide as before. Both ends
of the specimen were exposed to a visible
light polymerization unit as before for 20
seconds. After storage for 24 hours as before,
they were placed in a microtomography unit
(No. 1172, Bruker MicroCT) and scans of
the samples were made. Recorded images
were then reconstructed (NRecon, version
1.4.4, Bruker MicroCT) into 3-dimensional
images, which were analyzed using proprietary software (CT Analyzer, version 1.6.0.0,
Bruker MicroCT) for percent porosity.
A mean and standard deviation were
determined per group. Data were analyzed
with a 1-way ANOVA and Tukey’s post
hoc tests per test type (α = 0.05). Due to
the non-normal distribution of the data,
percent porosity was evaluated with the
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May/June 2015
General Dentistry
nonparametric Kruskal-Wallis and MannWhitney tests. A Bonferroni correction was
applied because multiple comparison tests
were completed simultaneously (α = 0.005).
Results
Significant differences were found between
groups per test type (P < 0.05) (Table 2).
For the depth of cure measurements, all
the groups were significantly different
from each other. QuiXX had the greatest
depth of cure (6.31 ± 0.02 mm) and Filtek
LS had the lowest (2.06 ± 0.02mm). Tetric
EvoCeram Bulk Fill, Filtek Z250, and
SonicFill performed more moderately.
Filtek LS had the lowest polymerization
shrinkage (1.21% ± 0.08%). SonicFill and
QuiXX had low shrinkage and were not
significantly different from each other.
QuiXX was not significantly different from
Filtek Z250.Tetric EvoCeram Bulk Fill had
the greatest shrinkage (2.31% ± 0.11%).
Filtek Z250 had the greatest flexural
strength (139.41 ± 16.35 MPa), but it was
not significantly different from SonicFill.
TetricEvoCeram Bulk Fill had the lowest
flexural strength (101.41 ± 5.86 MPa),
but it was not significantly different from
QuiXX and Filtek LS.
QuiXX had the greatest flexural modulus (13.34 ± 0.84 GPa). Filtek Z250 and
SonicFill had more moderate flexural
moduli and were not significantly different
from each other. Tetric EvoCeram Bulk
Fill had the lowest flexural modulus (8.55
± 0.55 GPa), but it was not significantly
different from Filtek LS.
Filtek Z250 had the greatest fracture
toughness (0.62 ± 0.08 MPa m½), but it
was not significantly different from QuiXX
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or SonicFill. Tetric EvoCeram Bulk Fill and
Filtek LS had the lowest fracture toughness
(0.52 ± 0.05 MPa m½), but they were not
significantly different from SonicFill.
SonicFill had the lowest percent porosity
(0.02% ± 0.04%). QuiXX had the greatest
porosity (1.42% ± 1.17%). Filtek LS, Tetric
EvoCeram Bulk Fill, and Filtek Z250 had
more modest porosity formation and were
not significantly different from each other.
Discussion
The null hypothesis was rejected in this
study. Statistically significant differences in physical properties were found
between composite resins per test type.
Very little published research is available evaluating the depth of cure of the
new bulk-fill composite resin restorative
materials. In this study, using the ISO
4049 standard, SonicFill’s average depth
of cure was 3.67 mm. Recent studies by
Garcia et al and Benetti et al found similar
depths of cure of 3.46 mm and 3.43 mm,
respectively, using the same ISO 4049
standard.26,27 Other studies have concluded
that the ISO 4049 method is very liberal,
and may overestimate the depth of cure
compared to other techniques, such as
hardness or degree of conversion.27,28 The
depth of cure for SonicFill (3.67mm)
was slightly less than Filtek Z250’s average depth of cure of 3.79 mm, which
is recommended by the manufacturer
for placement in incremental layers of
only 2.5 mm.29 The composite resin
which had the highest depth of cure was
QuiXX at 6.31mm, which exceeded the
manufacturer’s claim of 4.2 mm.30 The
greater depth of cure may be due to the
QuiXX
Filtek LS
Tetric EvoCeram
Filtek Z250
SonicFill
Figure. Representative specimens from each group with porosity formation.
translucent appearance of QuiXX when
completely polymerized. Tetric EvoCeram
Bulk Fill also met the manufacturer’s claim
of a 4 mm bulk fill.31 The manufacturer
states that in addition to the traditional
camphorquinone/amine photoinitiator
system, it contains Ivocerin, an “initiator
booster” which reportedly contributes to
the increased depth of cure.23 The manufacturer of SonicFill recommends that it be
cured with 10 seconds of additional light
curing on the buccal and lingual surfaces
after the initial 20 second light cure from
the occlusal.20 Additional light curing
from the proximal would likely increase
the polymerization of the other composite resins tested in this study. However,
laboratory studies have shown that enamel
and dentin significantly attenuate the light
from a curing unit.32 Limited research has
been completed on the effects of tri-sited
light curing on the depth of cure of bulkfill composites.
Studies evaluating the efficacy of
incremental versus bulk filling have been
somewhat equivocal, with higher shrinkage stress and cuspal deflection in some
studies but reduced cuspal deflection in
others.33 Incremental layering may allow
flow during curing with additional free
surface area. However, incremental curing
allows more maximum polymerization
and potentially more shrinkage stress.
Little clinical evidence exists to support
one particular composite resin application
method over another.4
Polymerization shrinkage has been
steadily reduced through improvements
in chemistry and composition.8 A new
composite resin, Filtek LS, is promoted
as a low-shrinking composite resin based
on a ring-opening polymerization mechanism.34 As expected, Filtek LS had the
lowest shrinkage of all of the composite
resins tested (1.21%). SonicFill had the
second lowest polymerization shrinkage of
(1.88%), although it was not significantly
different from QuiXX (2.00%). However,
all the composite resins tested exhibited
relatively volumetric low shrinkage. An
average volumetric shrinkage of 2%-3%
occurs when restorative composite resins
are polymerized, with the ring-opening
silorane-based composite, Filtek LS,
reportedly approaching 1%.1,22
For restorations exposed to greater
mechanical loads, the ideal minimum flexural strength is 90-100 MPa.35 In addition,
a relatively high modulus is expected from
posterior composite resin restorations to
withstand the occlusal forces and preserve
the adhesive interface.13 All composite
resins tested showed adequate flexural
strength and flexural moduli, although
there were statistically significant differences among groups.
Another important mechanical property
for dental composite resin materials is fracture toughness, which indicates the relative
resistance to crack propagation from the
surface or inherent flaws in the materials.36
Resin composites with higher fracture
toughness will be better able to withstand
high stress levels and thus have improved
clinical outcomes.37 Filtek Z250 and
QuiXX had the highest relative fracture
toughness values, while SonicFill, Filtek LS,
and Tetric EvoCeram Bulk Fill had slightly
lower fracture toughness values. Despite
the statistical differences, the results of this
study show that all the restorative materials
tested have adequate fracture toughness for
use in posterior restorations.4
Voids within a composite resin restoration may cause marginal leakage and
discoloration, increased wear (due to
stress concentration around the voids),
decreased flexural strength, and incomplete adhesion between the resin composite and tooth structure.38 These voids
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may be incorporated into the composite
material due to the manufacturing process
or from handling techniques during clinical placement. With the new sonically
placed composite resin, it was unknown
if sonic energy would have an influence
on the number and size of porosities. The
results of this study showed less porosity
with SonicFill, at least within the body of
the specimen, as compared to the other
composite resins tested (Figure). QuiXX
had the largest number of porosities.
Significant variability in porosity was
found in the composite resins tested. The
variability may be due to differences in
handling characteristics of the different
composite resin and the subsequent inclusion of larger voids during the fabrication
of the specimens.
Overall, SonicFill has satisfactory
mechanical properties for use as a direct
posterior composite resin restorative material. The potential convenience of sonic
placement and the advantage of the reduction in viscosity would likely be operatordependent preferences. However, a
disadvantage of SonicFill is that the depth
of cure was determined to be significantly
less than the other bulk-fill composites
tested in this study. Furthermore, although
the composite resin refill compules are
similar in price to other comparable
materials, the restorative dentist would
incur an additional expense per each
SonicFill handpiece and coupler. More
research is necessary to evaluate the clinical
performance of this new sonically placed
composite resin material and the new class
of bulk-fill restorative materials.
Conclusion
Compared to the other composite resin
restorative materials, SonicFill showed low
shrinkage and percent porosity, moderate
fracture toughness and flexural modulus,
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Dental Materials Physical properties of a new sonically placed composite resin restorative material
and high flexural strength. However, it had
a relatively reduced depth of cure compared to the other composites.
Author Information
Maj Ibarra is Chief of Dental Services at
Pope AFB, North Carolina. Lt Col Lien
is Director of Dental Materials Evaluation
and Testing, US Air Force (USAF) Dental
Evaluation and Consultation Service,
Fort Sam Houston, Texas. Lt Col Casey is
Chief of Restorative Dentistry, Sheppard
AFB, Texas. Col Dixon is Director of
Orofacial Pain, Keesler AFB, Mississippi.
Col (ret) Vandewalle is Director of
Dental Research, Advanced Education
in General Dentistry Residency of the
USAF Postgraduate Dental School, JointBase San Antonio, Lackland, Texas, and
Uniformed Services University of the
Health Sciences, Bethesda, Maryland.
Disclosure
The views expressed in this study are those
of the authors and do not reflect the official
policy of the United States Air Force, the
Department of Defense, or the United
States Government. The authors do not
have any financial interest in the companies
whose materials are discussed in this article.
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10. Cobb DS, MacGregor KM, Vargas MA, Denehy GE. The
physical properties of packable and conventional posterior resin-based composites: a comparison. J Am
Dent Assoc. 2000;131(11):1610-1615.
11.de Camargo EJ, Moreschi E, Baseggio W, Cury JA,
Pascotto RC. Composite depth of cure using four polymerization techniques. J Appl Oral Sci. 2009;17(5):
446-450.
12. Rodrigues SA Jr, Ferracane JL, Della Bona A. Flexural
strength and Weibull analysis of a microhybrid and a
nanofill composite evaluated by a 3- and 4-bendingtests. Dent Mater. 2008;24(3):426-431.
13. Rodrigues SA Jr, Zanchi CH, Carvalho RV, Demarco FF.
Flexural strength and modulus of elasticity of different
types of resin-based composites. Braz Oral Res. 2007;
21(1):16-21.
14. Ferracane JL, Choi KK, Condon JR. In vitro wear of
packable dental composites. Compend Contin Educ
Dent Suppl. 1999;(25):S60-S66; quiz S74.
15. Ilie N, Hickel R. Investigations on mechanical behaviour of dental composites. Clin Oral Investig. 2009;
13(4):427-438.
16. Ferracane JL, Moser JB, Greener EH. Rheology of composite restoratives. J Dent Res. 1981;60(9):1678-1685.
17. Denehy GE, Vargas M, Cobb DS. Achieving long-term
success with class II composite resins. Calif Dent Inst
Contin Educ. 1996;59:27-36.
18. Tanimoto Y, Nishiwaki T, Nemoto K. Dynamic viscoelastic behavior of dental composites measured by Split
Hopkinson pressure bar. Dent Mater J. 2006;25(2):
234-240.
19. Opdam NJ, Roeters JJ, Peters TC, Burgersdijk RC, Kuijs
RH. Consistency of resin composites for posterior use.
Dent Mater. 1996;12(6):350-354.
20. Kerr Corporation. SonicFill. Sonic-Activated, Bulk-Fill
Composite [product description]. Available at: http://
www.kerrdental.com/kerrdental-composites-sonicfill-2.
Accessed November 17, 2014.
21. Sideridou ID, Karabela MM, Vouvoudi EC. Physical
properties of current dental nanohybrid and nanofill
light-cured resin composites. Dent Mater. 2011;27(6):
598-607.
22. Lien W, Vandewalle KS. Physical properties of a new
silorane-based restorative system. Dent Mater. 2010;
26(4):337-344.
23. Ilie N, Bucuta S, Draenert M. Bulk-fill resin-based composites: an in vitro assessment of their mechanical
performance. Oper Dent. 2013;38(6):618-625.
24. International Organization for Standardization. ISO
4049. Dentistry - Polymer-Based Filling Restorative
Materials. Available at: http://www.iso.org/iso/catalogue_detail.htm?csnumber=42898. Accessed February 9, 2015.
25. Bisco, Inc. Determination of the Rate of Curing of
Composites by Acovol. Available at: https://www.bisco.com/rp/Sharp965.pdf. Accessed February 10, 2014.
26. Garcia D, Yaman P, Dennison J, Neiva GF. Polymerization shrinkage and depth of cure of bulk-fill flowable
composite resins. Oper Dent. 2014;39(4):441-448.
27. Benetti AR, Havndrup-Pedersen, Honore D, Pedersen
MK, Pallesen U. Bulk-fill Resin composites: polymerization contraction, depth of cure, and gap formation.
Oper Dent. 2014. [Epub ahead of print]
28. Moore BK, Platt JA, Borgess G, Chu TM, Katsilieri I.
Depth of cure of dental resin composites: ISO 4049
depth and microhardness of types of materials and
shades. Oper Dent. 2008;33(4):408-412.
29. 3M ESPE. Filtek Z250 [product information]. Available
at: http://solutions.3m.com/wps/portal/3M/en_US/
www.agd.org
3M-ESPE-NA/dental-professionals/products/especatalog/~/Filtek-Z250-Universal-Restorative?N=5145
652+3294735755+3294735961&rt=rud. Accessed
February 10, 2015.
30. DENTSPLY Caulk. QuiXX Restorative [product information]. Available at: http://www.dentalproductshopper.
com/quixx-restorative. Accessed February 10, 2015.
31. Ivoclar Vivadent, Inc. Tetric EvoCeram Bulk Fill [product
information]. Available at: http://www.ivoclarvivadent.
com/en/products/restorative-materials/composites/
tetric-evoceram-bulk-fill. Accessed February 10, 2015.
32. Flury S, Hayoz S, Peutzfeldt A, Husler J, Lussi A. Depth
of cure of resin composites: is the ISO 4049 method
suitable for bulk fill materials? Dent Mater. 2012;
28(5):521-528.
33. Price RBT, Murphy DG, Derand T. Light energy transmission through cured resin composite and human
dentin. Quintessence Int. 2000;31(9):659-667.
34. 3M ESPE. Filtek LS [production information]. Available
at: http://www.3m.com/product/information/ESPEFiltek-LS-Posterior-Restorative.html. Accessed February
10, 2015.
35. Kwon Y, Ferracane J, Lee IB. Effect of layering methods,
composite type, and flowable liner on the polymerization shrinkage stress of light cured composites. Dent
Mater. 2012;28(7):801-809.
36. Heintze SD, Zimmerli B. Relevance of in vitro tests of
adhesive and composite dental materials, a review in
3 parts. Part 1: approval requirements and standardized testing of composite materials according to ISO
specifications [article in Dutch, English]. Schweiz
Monatsschr Zahnmed. 2011;121(9):804-816.
37. Jun SK, Kim DA, Goo HJ, Lee HH. Investigation of the
correlation between the different mechanical properties of resin composites. Dent Mater. 2013;32(1):48-57.
38. Elbishari H, Silikas N, Satterthwaite J. Filler size of resin-composites, percentage of voids and fracture toughness: is there a correlation? Dent Mater. 2012;31(4):
523-527.
Manufacturers
Bisco, Inc., Schaumburg, IL
800.247.3368, www.bisco.com
Blue Light Analytics, Inc., Halifax, Canada
902.407.4242, www.curingresin.com
Bruker MicroCT, Kontich, Belgium
32.3877.5705, www.skyscan.be
Coherent, Inc., Santa Clara, CA
800.227.8840, www.coherent.com
DENTSPLY Caulk, Milford, DE
800.532.2855, www.caulk.com
Grobet USA, Carlstadt, NJ
800.847.4188, www.grobetusa.com
Ivoclar Vivadent, Inc., Amherst, NY
800.533.6825, www.ivoclarvivadent.us
Kerr Corporation, Orange, CA
800.537.7123, www.kerrdental.com
MTS Systems Corporation, Eden Prairie, MN
899.328.2255, www.mts.com
Nikon USA, Melville, NY
631.547.4200, www.nikonusa.com
Sabri Dental Enterprises, Inc., Downers Grove, IL
630.916.1471, www.sabridentalenterprises.com
3M ESPE, St. Paul, MN
888.364.3577, solutions.3m.com
Exercise No. 368 Dental
Materials Subject Code 017
The 15 questions for this exercise are based on the
article, Physical properties of a new sonically placed
composite resin restorative material, on pages 51-56.
This exercise was developed by Jean J. Carlson, DDS,
FAGD, in association with the General Dentistry
Self-Instruction Committee.
1. The most common cause of failure of
composite restorations is _________.
A. improper material selection
B. incomplete curing
C. recurrent caries
D. occlusal overload
2. Heavily filled resins have a maximum
filler volume of about ____%.
A. 40
B. 50
C. 60
D. 70
3. Heavily filled composite resins exhibit
all of the following improvements
in handling except one. Which is the
exception?
A. marginal adaptability
B. mechanical strength
C. fracture properties
D. wear resistance
4. Flowable composite resins exhibit all of
the following traits except one. Which
is the exception?
A.decreased filler concentration
B. lower viscosity
C.decreased filler wettability
D.lower elastic modulus
5. The ability of a composite material
to flow may play a major role in the
success of a restoration. In many Class II
cavity preparations, it is easy to obtain
proper contour and contacts.
A.Both statements are true.
B. The first statement is true;
the second is false.
C.The first statement is false;
the second is true.
D.Both statements are false.
Reading the article and successfully completing this exercise will enable you to:
•understand the physical properties of heavily filled resins compared with
flowable resins;
•recognize the differences between bulk-fill and packable composite resins; and
•understand the advantages and disadvantages of a sonic-activated bulk-fill
composite material.
6. SonicFill reportedly can be used in
cavity preparations up to ___ mm deep
with only 20 seconds of light curing.
A.3
B.4
C.5
D.6
7. Microfill composite resins contain fillers
with an average particle size in the
range of ________ µm.
A.0.16-0.20
B.0.11-0.15
C.0.06-0.10
D. 0.01-0.05
8. The silorane ring expansion of
Filtek LS has been shown to decrease
polymerization shrinkage to <______%.
A.0.5
B.1.5
C.2.5
D.3.5
9. All of the following properties were
evaluated in the study except one.
Which is the exception?
A.depth of cure
B. polymerization shrinkage
C.flexural strength
D.internal translucency
10. The greatest depth of cure was
exhibited by the _________ composite
resin.
A.Filtek LS
B.SonicFill
C.QuiXX
D.Filtek Z250
11. SonicFill demonstrated an average
depth of cure of _____ mm.
A.3.17
B.3.67
C.4.17
D.4.67
12. Incremental layering may inhibit flow
during curing. Incremental curing
allows maximum polymerization.
A.Both statements are true.
B. The first statement is true;
the second is false.
C.The first statement is false;
the second is true.
D.Both statements are false.
13. For restorations exposed to greater
mechanical loads, the ideal minimum
flexural strength is ________ MPa.
A.90-100
B.80-89
C.70-79
D.60-69
14. Which of the following restorative
materials was found to have the
highest relative fracture toughness?
A.QuiXX
B.SonicFill
C.Filtek LS
D.TetricEvoCeram
15. All of the following are characteristics
of SonicFill except one. Which is the
exception?
A.high shrinkage
B. high flexural strength
C.moderate fracture toughness
D.low percent porosity
Answer form is on the inside back cover. Answers for this exercise must be received by April 30, 2016.
www.agd.org
General Dentistry
May/June 2015
57
Cracked Tooth & Restorations
Fracture resistance of weakened roots restored
with different intracanal retainers
Juliana Broch, MSD n Ana Maria Estivalete Marchionatti, DDS, MSD n Cesar Dalmolin Bergoli, MSD, PhD Luiz Felipe Valandro, MSD, PhD n Osvaldo Bazzan Kaizer, MSD, PhD
The purposes of the study were to evaluate the effect of mechanical cycling (MC) on the fracture resistance of endodontically treated weakened
roots restored with different intraradicular retainers and to analyze the
failure mode. Eighty bovine roots were prepared and restored: 20 roots
were reconstructed with cast post-and-cores (CPCs); 20 with fiber posts
(FPs); 20 with fiber posts with larger coronal diameter (FPLs); and 20 with
anatomic posts (APs). Metal crowns were cemented in all the roots. Half
of specimens from each restoration strategy (n = 10) were submitted to
MC: CPC-MC, FP-MC, FPL-MC, and AP-MC. The specimens were subjected
to a fracture resistance test. The results showed that the type of retainer
T
he restoration of endodontically
treated teeth is a complex procedure. It
becomes even more challenging when
the radicular canals are excessively weakened due to substantial loss of tooth structure. If more than half of the coronal tooth
structure is lost due to carious lesions, fractures, or extensive cavity preparation, it is
necessary to use an intraradicular retainer.1-3
However, intracanal anchorage does not
reinforce or protect the remaining dental
structure. As such, the primary objective in
cases of substantial loss of tooth structure is
the retention of the material used to reconstruct the tooth crown.1,3-5 For selection of
the intracanal retainer, the rigidity of the
material should be considered since it may
influence the mechanical behavior of the
reconstructed tooth.3,5 Therefore, the use
of posts with rigidity values (modulus of
elasticity) higher than that of dentin—such
as cast post-and-cores (CPCs), metallic
prefabricated posts, and ceramic posts—
may increase the risk of root fracture.5-7
Conversely, posts with properties similar to
dentin, such as fiber-reinforced posts (glass,
carbon, quartz, or polyethylene), support
the material of coronal reconstruction and
the weakened dentin structure.2,5 These
types of posts also transmit less tension to
the root, so that it is likely that the post will
fail before the remaining root fractures.8,9
Considering the intraradicular retainer
systems available for use in enlarged
canals, CPCs—despite providing adequate adaptation to the canal walls—may
58
May/June 2015
General Dentistry
used was statistically significant (P < 0.0004). The CPC specimens
demonstrated a fracture resistance similar to that of the APs, but greater
than that of the FPs and FPLs. MC was statistically significant (P < 0.003)
and affected AP-MC fracture resistance, which was lower than that of
CPC-MC and similar to those of FP-MC and FPL-MC.
Received: July 1, 2013
Accepted: October 9, 2013
Key words: nonvital tooth, fracture resistance, weakened teeth
produce a wedge effect, which could
lead to root fracture.2,10-12 Conversely,
prefabricated fiber posts (FPs) have the
advantage of allowing more homogeneous stress distribution to the tooth
structure due to having mechanical
properties similar to dentin, but they
usually adapt imprecisely to the conduit,
generating a thicker cement layer around
the post.4,7,13 To overcome this problem,
anatomic posts (APs) and double-tapered
fiber posts with a larger coronal diameter
(FPLs) can be used to obtain better adaptation and retention to the root canal.
APs and FPLs can also reduce the thickness of the cement in the post-dentin
interface in cases with increased internal
radicular destruction.5,14,15
The use of APs is especially recommended for flared root canals when
removing extra dentin structure is
not indicated. The layer of composite
resin surrounding the AP—in order to
individualize the retainer to the canal—
eliminates the need to enlarge the conduit
to enable the post to fit or to apply an
extremely thick cement layer in the space
between the post and dentin.14 The use
of an AP also improves the retention of
the post by providing close contact of the
relining resin and the canal walls, as well
as a thin cement layer.15,16 FPL systems,
which have the same apical and middle
diameters as an FP but a larger coronal
diameter, have been recently developed as
alternative options for flared roots with
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cervical dentin loss.5 Moreover, the proposed configuration of FPLs provides an
adequate adaptation in the cervical portion without excessive removal of sound
tissue in the apical region.
It is known that in the oral environment,
dental reconstructions usually fail due to
damage caused by cumulative effects such
as fatigue, which differs from what occurs
in monotonic tests that apply a unique
static load until a specimen fails.17,18 For
that reason, aging by means of mechanical
cycling (MC) is a method of evaluating the
behavior of different restorative systems by
1 mm
5 mm
5 mm
15 mm
4 mm
1 mm
Fig. 1. Representation of specimen weakening.
A
B
C
D
Fig. 2. Schematic representation of the experimental groups. A. Cast post-and-cores. B. Fiber posts.
C. Fiber posts with larger coronal diameter. D. Anatomic posts.
approximately simulating actual clinical
conditions, such as the angle of the applied
load and the frequency of application.19
Within this context, the purposes of
the study were to evaluate the effect of
MC on fracture resistance of endodontically treated weakened teeth restored with
different intraradicular retainers and to
analyze the failure mode after compressive
testing. The null hypotheses tested were
that the different retainers would present
similar values of fracture resistance and
that MC would not affect the values.
Materials and methods
Selection and adequacy of
the specimens
Eighty single root bovine teeth were
sectioned to standardize the root lengths
at 15 mm. The coronal diameters of
the canals were measured with a digital
caliper (Starrett 727, The L.S. Starrett
Company); teeth with diameters larger
than the drill used to prepare the conduits
(1.8 mm) were excluded. The roots were
endodontically treated with stainless
steel K Flexofile reamers (DENTSPLY
International) at a working length of 1
mm coronal to the root apex, using 2 ml
of 1% sodium hypochlorite after the use of
each instrument. After instrumentation,
17% EDTA trisodium gel was applied
for 2 minutes and then removed from the
canals with 1% sodium hypochlorite. The
canals were obturated with gutta percha
master cones and calcium hydroxide endodontic cement Sealer 26 (DENTSPLY
International). Lateral condensation was
performed with finger spreaders and
accessory gutta percha points.
Canal preparation and weakening
The canals were partially de-obturated to a
depth of 10 mm with Largo Peeso reamers
(DENTSPLY International) of increasing
diameter (up to No. 4) until a diameter
of 1.3 mm was reached. The canals were
then prepared with a White Post DC No.
2 drill (FGM Produtos Odontologicos)
to a 10 mm length. In order to simulate
extensively enlarged canals, the most
cervical 5 mm of all roots were weakened
with a diamond-tapered bur (4138 HL,
KG Sorensen) until the remaining dentin
thickness was 1 mm (Fig. 1).
Embedment and periodontal
ligament simulation
To simulate the periodontal ligament,
the external surface of the roots was
covered by a uniform 0.3 mm layer of
wax, except for the last 3 mm of the
cervical portion.20 Each root was then
embedded in plastic cylinders with autocuring acrylic resin (Dencrilon, Dencril
Produtos Odontologicos); the bur of the
post system was inserted into the prepared canal and attached to a surveyor
so that the long axes of the root, bur,
and cylinder were perpendicular to the
ground. Acrylic resin was poured inside
the cylinders up to the last 3 mm of the
coronal portion of the roots.21 After the
acrylic resin had polymerized, the roots
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were taken off the cylinder and the wax
was removed. Medium-bodied polyether
(Impregum Soft, 3M ESPE) was manipulated and inserted in the space left by the
wax removal. The root was repositioned
on the cylinder and the excess was
removed with a scalpel blade after the
polymerization of the Impregum Soft.
All specimens were numbered from 1 to
80, and 8 random sequences of 10 numbers (n = 10) were generated by Random
Allocation Software (M. Saghaei, Isfahan
University of Medical Sciences), according to the retainer type and application of
MC (Fig. 2).
Preparation of the specimens
CPCs
CPCs were made with a chemically
curing acrylic resin (Duralay, Reliance
Dental Mfg. Co.) and cast with Ni–Cr
alloy (Fit Cast-SB Plus, Talmax). To standardize the dimensions and shape of the
coronal portion of the cores, the acrylic
resin was inserted in polypropylene matrices with the anatomic configuration of
an upper canine prepared for a full crown
(6 mm height).
The CPCs were abraded with aluminum oxide (particle size 50 µm). Coronal
and radicular dentin was etched with
37% phosphoric acid (Condac, FGM
Produtos Odontologicos) for 15 seconds
and washed with water for 15 seconds.
Excess water was removed with paper
points. An adhesive (Ambar, FGM
Produtos Odontologicos) was applied to
the canal with a microbrush (Cavibrush,
FGM Produtos Odontologicos) and
photoactivated for 20 seconds with a
high power LED (Radii Cal, SDI (North
America), Inc.). Next, a dual resin cement
(AllCem, FGM Produtos Odontologicos)
was mixed and inserted into the canal
with a Lentulo drill. The CPCs were
positioned, excess cement was removed,
and photoactivation was performed
for 10 seconds on each surface (buccal,
mesial, lingual, and distal).
FPs
Smooth, double-tapered FPs (White Post
DC No. 2, FGM Produtos Odontologicos)
with apical diameter of 1.05 mm and coronal diameter of 1.8 mm were cemented
on the roots of the 20 specimens. Before
cementation, the FPs were cleaned
General Dentistry
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59
Cracked Tooth & Restorations Fracture resistance of weakened roots restored with different intracanal retainers
with 70% ethyl alcohol and a silanecoupling agent (Prosil, FGM Produtos
Odontologicos) was applied all over the
FPs with a microbrush. The cementation technique used for those groups was
identical to that used for the CPCs. After
cementation, a layer of composite resin
(Oppalis, FGM Produtos Odontologicos)
was applied over the coronal portion of the
FPs to avoid the incorporation of bubbles
and to ensure that the entire post surface
was covered by resin. Photoactivation was
performed for 10 seconds on each surface,
for a total of 40 seconds. Then, plastic
matrices identical to those used for the
CPCs were filled with the composite resin,
positioned over the coronal portion of the
FPs, and photoactivated for 10 seconds on
each surface. After the resin polymerization, the matrices were removed and the
cores presented the same anatomic shape
and dimensions as the CPCs.
FPLs
FPLs (White Post DC No. 2E, FGM
Produtos Odontologicos) were cemented
on the roots of 20 specimens. These FPLs
had the same apical diameter as the FPs but
a larger coronal diameter (2.2 mm); they
are recommended by the manufacturer for
use in flared canals.22 Post cementation and
coronal reconstruction were identical to the
methods used for the FPs.
APs
To produce APs, White Post DC No. 2
FPs were relined inside the canals with
a low-viscosity composite resin (Oppalis
Flow, FGM Produtos Odontologicos) in
order to provide adequate adaption to
the enlarged root conduit. The FPs were
cleaned with 70% ethyl alcohol and Prosil
(FGM Produtos Odontologicos) was
applied over the surface. Ambar adhesive
was applied to the APs and photoactivated
for 20 seconds. The root canals were
lubricated with hydrosoluble insulation
(K-Y Jelly, Johnson & Johnson) and
composite resin was inserted in the canal
with the Lentulo drill. The fiber post was
positioned in the center of the conduit and
photoactivation was performed for 20 seconds on the occlusal surface. The relined
post was removed from the canal and additional photoactivation was performed for
10 seconds on each surface. Subsequently,
the canals were washed with distilled water
60
May/June 2015
General Dentistry
Table 1. Fracture resistance means and standard deviations (N)
for the experimental groups in the study.
Mechanical cycling
Retainer
Without
With
CPC
1396.8 (265.95)
FP
976.7 (236.28) B,a
1017.4 (230.70) AB,a
FPL
927.3 (177.29)
896.5 (150.97) AB,a
AP
A,a
B,a
1103.5 (192.15) AB,a
1120.0 (242.26) A,a
780.0 (200.83) B,b
Different uppercase letters indicate a clinically significant difference ( P < 0.05) for the same column. Different
lowercase letters indicate a clinically significant difference ( P < 0.05) for the same row. Abbreviations: AP, anatomic
posts; CPC, cast post-and-cores; FP, fiber posts; FPL, fiber posts with larger coronal diameter.
to remove the insulation. The adhesive
procedures of post cementation and coronal reconstruction described for FPs and
FPLs were conducted.
Cementation of full metal crowns
After cementation, all specimens were
stored in distilled water at a temperature
of 37°C for 24 hours. Identical full metal
crowns simulating the anatomy of upper
canines (8 mm in height and a slightly
rounded concavity located 3 mm from
the incisal edge on the palatal aspect)
were cemented over the coronal portion
of the casts in the roots of all the groups.
The functions of the concavity were to
prevent the sliding of the active end of
the testing machine and to establish
the same point of load application for
all the specimens. The crowns were
internally abraded with particles (50
µm) of aluminum oxide. AllCem was
inserted inside the crowns, which were
then settled in position over the casts,
and a weight of 2 kg was applied on the
crowns. Photoactivation was performed
for 40 seconds (10 seconds on each face)
and the load was removed after 5 minutes, allowing chemical polymerization
of the cement. After cementation of the
crowns, the specimens were stored in
distilled water at 37°C for 24 hours.
Mechanical cycling
Half of the specimens of each restorative
strategy were immersed in distilled water
and subjected to 100,0000 cycles in the
mechanical fatigue simulator (ER 11000,
ERIOS Equipamentos), corresponding to
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1 year of clinical service, according to an
MC protocol: load of 88 N, frequency of
2.2 Hz, temperature of 37°C, and angle
of 45 degrees to the specimen long axis
(135 degrees in relation to the ground).19
The specimens that were not mechanically cycled were stored in distilled water
at a temperature of 37°C during the same
period of the MC specimens. According
to the type of retainer used and presence
or absence of MC, the following 8 groups
were designed: CPC, FP, FPL, and AP (no
MC); and CPC-MC, FP-MC, FPL-MC,
and AP-MC (with MC).
Compressive strength test
The fracture resistance test was executed
in a universal testing machine (EMIC DL
2000, EMIC Equipamentos e Sistemas de
Ensaio LTDA) for all groups (MC and no
MC) 24 hours after the MC was finished.
The specimens were positioned in a device
at an angle of 45 degrees in relation to the
horizontal plane, reproducing the clinical
condition of a Class I occlusion. A constant load was applied at a crosshead speed
of 1 mm/min until failure.
Failure mode analysis
Failures were classified as favorable or unfavorable. Vertical and oblique root fractures
below the simulated bone level (the tooth
area exposed outside the acrylic resin, corresponding to the biologic space) were considered unfavorable failures. Failures at or
above the simulated bone level, fractures of
the coronal portion of the cast, and dislodgment of the coronal portion of the cast and/
or post were considered as favorable failures.
Table 2. Percentage of failure modes for each group in the study.
Without MC
With MC
Failure modes
CPC
FP
FPL
AP
CPC-MC
FP-MC
FPL-MC
AP-MC
Favorable
30
90
90
80
0
80
80
70
Unfavorable
70
10
10
20
100
20
20
30
Abbreviations: AP, anatomic posts; CPC, cast post-and-cores; FP, fiber posts; FPL, fiber posts with larger coronal
diameter; MC, mechanical cycling.
Statistical analysis
Considering the 2 variables of the study
(type of retainer and MC), the fracture resistance values were analyzed by 2-way analysis
of variance (ANOVA) and Tukey’s test (α =
0.05). Comparisons were done among the
different retainers under the same cycling
options (present or absent) and for the same
retainers (MC and no MC).
Results
None of the specimens presented root
fracture or restoration failure during the
MC. Two-way ANOVA showed that the
type of intraradicular retainer, MC, and
the interaction between the 2 factors
were statistically significant (P < 0.0004,
P < 0.003, and P < 0.02, respectively).
There were significant differences between
the CPC and FP, CPC and FPL, FP-MC,
and AP-MC groups, as well as the AP and
AP-MC groups (Table 1). Table 2 shows
the percentage of favorable and unfavorable failures in each group.
Discussion
Teeth that have severe coronal destruction
resulting from caries and/or dental fractures, as well as from the opening of the
pulp chamber for endodontic treatment,
make the retention of restorative materials
used for dental reconstruction difficult.
Evaluation of the mechanical behavior of
such dental elements is important, since it
is common to encounter widely enlarged
teeth in a routine clinical examination.
Several studies have evaluated the behavior of weakened roots, resulting in diverse
canal weakening levels and different preparation designs, as there is no standardized
protocol for the amount of remaining
radicular dentin for flared canal simulation.6,13,23-27 In the present study, the choice
was made to weaken the roots until 1 mm
of remaining dentin thickness was reached.
This procedure has been done by other
authors, as it is believed that the remaining
quantity is consistent with actual clinical
observations.6,23,27
Different rehabilitation procedures for
restoring teeth with widely flared root
canals have been investigated in many
studies with the intention of predicting which method makes the restoring
complex (root, intraradicular post,
cement, cast, and crown) more resistant
to masticatory loads, thus providing a less
damaging failure pattern in unsuccessful
cases.6,13,23,24,26,27 The results of the present study demonstrate that the fracture
resistance was influenced by the different
intraradicular retainers (P < 0.05), so the
first null hypothesis was rejected.
Comparing the different types of intraradicular retainers utilized for dental
reconstruction without MC, our results
demonstrated that the FP and FPL specimens had lower fracture resistance than
the CPCs. The finding is in accordance
with those of other studies, which emphasized the utilization of FPs for the reconstruction of partial or extremely destroyed
endodontically treated teeth due to the
fact that their physical and mechanical
properties—principally that the modulus
of elasticity is close to that of dentin—
were compatible and quite similar to those
of lost dental structure, thus serving as
artificial dentin.28-32 The CPC specimens
did not show statistical differences with
the APs, FPs, or the FPLs. The FP and
FPL specimens also did not show a statistical difference between themselves. The
higher fracture resistance shown by the
CPCs is in agreement with the results of
previous studies, which may be explained
by the high modulus of elasticity and the
homogeneous constitution of this type of
www.agd.org
retainer, which also resulted in reduced
bending of the cast-post assembly during
load application.26,33-35 In relation to the
roots reconstructed with AP—which
showed fracture resistance similar to that
of the CPC—it is probable that the accurate adaption and retention to the flared
canal walls provided by the relining of
the fiber posts with composite resin (thus
reducing the cement thickness around the
post) was an important factor in obtaining acceptable mechanical performance
in those teeth.14,15
Considering the utilization of doubletapered FPs, there was no statistical difference (regardless of MC) between the
groups restored with FPs and the groups
restored with FPLs. Although the FPLs
generated a thinner layer of cement, which
in terms of adhesion is favorable, the
greater diameter did not affect the compressive resistance values of the restorative
unit, which probably could be explained by
the standard weakening of all the groups.36
As a result of the canal preparation simulating weakened radicular walls, there was no
contact of the post with the canal walls in
the cervical portion of the conduit in the
groups of FPs and FPLs, even though the
posts were adapted in the apical third. It is
suggested that more laboratory and longterm clinical studies should be conducted
to test FPLs in root canals with different
weakening levels in order to verify whether
the larger diameter really provides significant resistance values, thereby enhancing
its indication for flared teeth.
The second hypothesis of the study was
rejected because MC had a significant
effect on the fracture resistance of the
retainers (P < 0.05). When the different
intraradicular retainers were compared
among themselves, it was observed that
the CPC-MC group showed fracture
resistance statistically similar to that
of the FP-MC, FPL-MC, and AP-MC
groups. Although the groups restored with
FPs and FPLs showed fracture strengths
inferior to those of other groups when
MC was not applied, these post systems
presented good mechanical behavior after
aging, and were the groups that showed
the lowest reduction in fracture resistance
after MC. This finding is directly related
to the mechanical and physical properties
of the retainers, which are very similar to
those of the dental structure and therefore
General Dentistry
May/June 2015
61
Cracked Tooth & Restorations Fracture resistance of weakened roots restored with different intracanal retainers
homogeneously dissipate the stresses
generated to the root.7 Moreover, this
result is in agreement with other studies
that also observed satisfactory behavior
for teeth restored with these kinds of
post systems.13,24,26,28,30
Comparing the MC and non-MC
groups, it was verified that only the
group reconstructed with APs showed
statistically inferior fracture resistance
after aging. These results highlight
another finding of the present study: the
AP behaved as well as the CPC group;
however, when MC was imposed, the
APs experienced a significant decrease in
fracture resistance. Because both systems
(APs and CPCs) had adequate adaptation to the canal walls (since they were
individualized retainers and the adhesive
systems were the same for all the groups),
it is possible that the weak component
of the APs was the low-viscosity composite resin used to reline the original
FPs. Therefore, the teeth reconstructed
with APs presented good behavior for
the static test, but after MC, the flowable resin apparently showed degradation, which was reflected in the lower
fracture resistance.
Compared to microhybrid resins, flowable composite resins present a reduction
in filler volume, which results in better
flowing properties, reduced viscosity,
lower modulus of elasticity, and easier
handling.37,38 However, certain studies have suggested that flowable resins
demonstrate decreased mechanical
properties, such as compressive resistance,
flexural resistance, and fracture toughness, which could explain the reduction
of fracture resistance when the specimens
were mechanically cycled in the present study.39,40 It is likely that if another
composite resin with greater inorganic
filler content—such as a hybrid or microhybrid resin—had been used, the cycled
anatomic posts would have had higher
compressive strength values.
Some studies did not find a significant
decrease in fracture resistance after
simulated aging with MC, which is in
accordance with the results shown for the
CPC and CPC-MC groups in the present
study, as well as for the FP and FP-MC
and the FPL and FPL-MC groups.26,41
With respect to the CPCs, in spite of not
being statistically significant, the MC
62
May/June 2015
General Dentistry
induced a reduction of fracture strength.
If a greater number of cycles had been
applied, it is reasonable to suppose that
such a reduction could be significant.
The primary advantage of FPs used
conventionally or individualized by the
relining of the canal with resin (APs),
was the more favorable failure mode (in
comparison with CPCs), which clinically
would allow for the recovery and maintenance of the dental element in almost
all the cases (70%-90% of repairable failures), which is in agreement with previous
studies.9,29,31,42 For that type of reconstruction, the materials have elasticity moduli
near to that of dentin, which provides a
more uniform stress distribution to the
remaining root and to the periodontium,
minimizing the risk of radicular fracture.3,5,6,7,10 In the groups in which CPCs
were used, the failure pattern was mostly
of irreparable failures (70%-100%), which
is also in agreement with prior studies; the
rigidity of this type of retainer generates
nonuniform high stresses to the remaining dental structure.6,7,9,41,42 It may also
have a wedge effect on the restored root,
leading to radicular fractures.10,11
Despite the advances in dentistry,
many professionals continue to choose
to extract flared dental elements for fear
of an adverse prognosis over the long
term.13 Nevertheless, radicular destruction
is usually restricted to the cervical portion of the canal, whereas the middle and
apical thirds have adequate radicular wall
thickness; hence, these partially weakened
roots could be maintained if adequately
restored.12 A correct diagnosis is indispensable for improved planning and for selection of the most suitable treatment option
to successfully restore endodontically
treated teeth with weakened roots.
Conclusion
CPCs, FPs, and FPLs remained stable after
MC, while MC significantly reduced the
fracture resistance of APs. CPCs promoted
a high percentage of irreparable failures,
while the other retainers generated a high
number of reparable failures.
Author information
Dr. Broch is in private practice. Dr.
Marchionatti is a doctoral student in
Oral Sciences, Federal University of Santa
Maria, Brazil, where Drs. Valandro and
www.agd.org
Kaizer are associate professors, Division of
Prosthodontics, Department of Restorative
Dentistry. Dr. Bergoli is an adjunct
professor, Division of Prosthodontics,
Department of Restorative Dentistry,
Federal University of Pelotas, Brazil.
Acknowledgments
The authors wish to thank Dencril Produtos
Odontologicos and FGM Produtos
Odontologicos for material donations.
Disclaimer
The authors have no financial, economic,
commercial, or professional interests
related to topics presented in this article.
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7. Lanza A, Aversa R, Rengo S, Apicella D, Apicella A. 3D
FEA of cemented steel, glass and carbon posts in a
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8. Stewardson DA. Non-metal post systems. Dent Update. 2001;28(7):326-332, 334, 336.
9. Varvara G, Perinetti G, Di Iorio D, Murmura G, Caputi S.
In vitro evaluation of fracture resistance and failure
mode of internally restored endodontically treated
maxillary incisors with differing heights of residual
dentin. J Prosthet Dent. 2007;98(5):365-372.
10. Yamamoto M, Miura H, Okada D, Komada W, Masuoka D. Photoelastic stress analysis of different post and
core restoration methods. Dent Mater J. 2009;28(2):
204-211.
11. Ukon S, Moroi H, Okimoto K, et al. Influence of different elastic moduli of dowel and core on stress distribution in root. Dent Mater J. 2000;19(1):50-64.
12. Lui JL. Composite resin reinforcement of flared canals
using light-transmitting plastic posts. Quintessence Int.
1994;25(5):313-319.
13. Bonfante G, Kaizer OB, Pegoraro LF, do Valle AL.
Fracture strength of teeth with flared root canals restored with glass fibre posts. Int Dent J. 2007;57(3):
153-160.
14. Grandini S, Sapio S, Simonetti M. Use of anatomic
post and core for reconstructing an endodontically
treated tooth: a case report. J Adhes Dent. 2003;
5(3):243-247.
15. Faria-e-Silva AL, Pedrosa-Filho Cde F, Menezes Mde S,
Silveira DM, Martins LR. Effect of relining on fiber post
retention to root canal. J Appl Oral Sci. 2009;17(6):
600-604.
16. Grandini S, Goracci C, Monticelli F, Borracchini A, Ferrari M. SEM evaluation of the cement layer thickness
after luting two different posts. J Adhes Dent. 2005;
7(3):235-240.
17. Scherrer SS, Wiskott AH, Coto-Hunziker V, Belser UC.
Monotonic flexure and fatigue strength of composites
for provisional and definitive restorations. J Prosthet
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18. Mair L, Padipatvuthikul P. Variables related to materials and preparing for bond strength testing irrespective of the test protocol. Dent Mater. 2010;26(2):
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19. Wiskott HW, Nicholls JI, Belser UC. Stress fatigue: basic principles and prosthodontic implications. Int J
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20. Soares CJ, Pizi EC, Fonseca RB, Martins LR. Influence
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21. Amaral M, Santini MF, Wandscher V, Amaral R, Valandro LF. An in vitro comparison of different cementation
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22. FGM Produtos Odontologicos. White Post [product
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23. Clavijo VG, Reis JM, Kabbach W, Silva AL, Oliveira
Junior OB, Andrade MF. Fracture strength of flared
bovine roots restored with different intraradicular
posts. J Appl Oral Sci. 2009;17(6):574-578.
24. Fukui Y, Komada W, Yoshida K, Otake S, Okada D, Miura H. Effect of reinforcement with resin composite on
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25. Goncalves LA, Vansan LP, Paulino SM, Sousa Neto
MD. Fracture resistance of weakened roots restored
with a transilluminating post and adhesive restorative materials. J Prosthet Dent. 2006;96(5):339344.
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aging on the fracture resistance of bovine roots with
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27. Zogheib LV, Pereira JR, do Valle AL, de Oliveira JA,
Pegoraro LF. Fracture resistance of weakened roots restored with composite resin and glass fiber post. Braz
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28. Akkayan B, Gulmez T. Resistance to fracture of endodontically treated teeth restored with different post
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the fracture resistance and failure mode of fiber, ceramic, and conventional post systems at various stages of restoration. J Prosthodont. 2001;10(1):26-36.
30. Mitsui FH, Marchi GM, Pimenta LA, Ferraresi PM. In
vitro study of fracture resistance of bovine roots using
different intraradicular post systems. Quintessence Int.
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of nine flowable resin composites. J Prosthet Dent.
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properties of new-generation flowable resin composites for dental restoration. Dent Mater. 2011;27(12):
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Manufacturers
Dencril Produtos Odontologicos, Pirrassununga, Brazil
55.19.3565.5660, www.dencril.com.br
DENTSPLY International, York, PA
800.877.0020, www.dentsply.com
EMIC Equipamentos e Sistemas de Ensaio LTDA,
San Jose de Pinhais, Brazil
55.42.3035.9400, www.emic.com.br
ERIOS Equipamentos, Sao Paulo, Brazil
11.2274.9466, eriosequipamentos.com.br
FGM Produtos Odontologicos, Joinville, Brazil
55.47.3441.6100, www.fgm.ind.br
Johnson & Johnson, Skillman, NJ
800.690.1826, www.jnj.com
KG Sorensen, Cotia, Brazil
55.11.4777.1061, www.kgsorensen.com.br
Reliance Dental Mfg. Co., Worth, IL
708.587.6694, reliancedental.net
SDI (North America), Inc., Bensenville, IL
800.228.5166, www.sdi.com.au
Talmax, Curitiba, Brazil
55.41.3888.5555, www.talmax.com.br
The L.S. Starrett Company, Athol, MA
978.663.9822, www.starrett.com
3M ESPE, St. Paul, MN
888.364.3577, solutions.3m.com
General Dentistry
May/June 2015
63
Dentistry for the Medically Compromised
Dental management of a patient
with Wilson’s disease
Paulo Sergio da Silva Santos, DDS, MsC, PhD n Karin Sa Fernandes, DDS, MsC, PhD n Alexandre Fraige, DDS, PhD Marina Gallottini, DDS, MsC, PhD
Wilson’s disease (WD) is an autosomal recessive genetic disease, characterized by the accumulation of copper in the body—primarily in the brain
and liver—due to defective biliary copper excretion by hepatocytes.
WD may manifest clinically as liver disease, neurologic symptoms, and
Kayser-Fleischer corneal rings. This article presents a case involving
a 43-year-old man who had WD prior to liver transplantation. Oral
examination revealed petechiae in the oral mucosa, poor oral hygiene,
periodontal disease, missing teeth, and several carious teeth. Patients
with WD may present systemic changes that affect dental care. Dental
W
ilson´s disease (WD) was first
described by Dr. Samuel Wilson
in 1912.1 He described it as a
“progressive hepatolenticular degeneration.” WD is relatively rare and occurs
equally among males and females; a 1999
study reported an estimated prevalence of
1:35,000 among Japanese patients.2
WD is an autosomal recessive genetic disease. It is characterized by the accumulation
of copper in the body (primarily in the brain
and liver) due to defective biliary copper
excretion by hepatocytes.3 The disease is
caused by mutations in the ATP7B gene
located in chromosome 13, which functions
as a biliary copper excretory pathway.3-5
Copper is essential for enzymatic reactions involving free radical scavenging,
pigment production, neurotransmission,
treatment prior to liver transplantation is recommended to eliminate the
oral foci of infection and control oral disease.
Received: December 16, 2013
Revised: May 27, 2014
Accepted: June 5, 2014
Key words: Wilson’s disease, liver transplantation,
coagulation abnormalities
connective tissue formation, and iron
homeostasis.6 However, copper accumulation in hepatocytes can cause severe
mitochondrial dysfunction with subsequent decreased enzymatic activity in the
liver, resulting in hepatic steatosis. When
the accumulation of copper exceeds
the liver’s capacity to metabolize it, the
copper is released into the circulatory
system and taken up by all organs. The
resultant copper toxicity mainly affects
the central nervous system, causing
neuronal damage.7
WD may manifest in a variety of clinical
conditions, such as liver disease, neurologic symptoms, and Kayser-Fleischer corneal rings; the latter are characterized by a
golden-brown ring of pigmentation at the
outer margin of the cornea. Manifestations
in the nervous system include a decline in
intellectual function, movement disorder,
depression, loss of emotional control, dystonia, orthostatic hypotension, parkinsonism, and an altered gag reflex.3,7,8
Treatment options depend on a patient’s
clinical manifestations. In asymptomatic
cases, the goal of therapy is to remove
copper from the tissues with a chelating
agent, such as penicillamine and zinc
acetate. Penicillamine is a reductive chelator that acts to mobilize copper from
the liver and other organs, causing its
excretion in the urine; however, there are
numerous (and often serious) side effects
to this agent, including bone marrow
suppression, hypersensitivity, proteinuria,
and autoimmune diseases. Zinc acetate
induces intestinal cell metallothionein,
Table. Results of the patient’s blood tests as compared to the normal range.
Tests
International normalized ratio
Patient’s results
Reference value (normal)
1.52
0.7-1.2
Partial thromboplastin time (seconds)
41.5
30-45
Prothrombin time (seconds)
19.6
11.0-14.6
Bleeding time (minutes)
2
1-4
Platelet count (No./mm3)
41,000
165,000-397,000
Aspartate amino transferase (units/liter)
30
8-20
Alanine amino transferase (units/liter)
30
10-40
Gamma glutamil transferase (units/liter)
58
2-30
64
May/June 2015
General Dentistry
www.agd.org
Fig. 1. Anterior photograph of patient’s left eye
showing a Kayser-Fleischer ring.
Fig. 2. Intraoral photograph of the patient’s mouth
showing petechiae in the oral mucosa.
Fig. 3. A pretreatment panoramic radiograph of the patient showing periodontal disease, missing teeth,
several carious teeth, and an impacted left mandibular third molar.
which inhibits the absorption of copper;
the only side effect of this agent is gastric
irritation.3 A patient with severe liver failure requires hepatic transplantation.8
There are few studies in the literature
that profile the oral health and dental
management of these patients. This article
presents a case report involving a patient
who had WD prior to a hepatic transplant
and discusses the oral aspects and dental
management of individuals with WD.
An intraoral examination identified
petechiae in the oral mucosa, poor oral
hygiene, periodontal disease, missing
teeth, and several carious teeth (Fig. 2).
Radiographic examinations (including
periapical and panoramic radiographs)
were also performed (Fig. 3). The treatment plan focused on preventing caries
and periodontal disease, restorative and
periodontal treatment, and tooth extraction. The restorations were replaced with
composite resin, avoiding alloys that
might release copper. Successive sessions
of scaling and root planning (SRP) were
performed around all teeth to prevent
gingival bleeding. To prevent caries and
periodontal disease, oral hygiene instructions concerning the control of plaque
were emphasized at each appointment. A
third molar surgery was conducted in an
outpatient clinic using local hemostatic
measures, tranexamic acid paste, and
absorbable gelatin sterile sponges.
Case report
A 43-year-old man who had been
diagnosed with WD 2 years earlier was
referred for dental treatment prior to
receiving a liver transplant. The patient
had no specific dental complaints. His
medical history included end-stage liver
disease requiring liver transplantation
and various neurological impairments,
including dystonia and parkinsonism.
The patient was taking medications (zinc
acetate and penicillamine) daily and had
reported no side effects. Laboratory tests
showed significant changes in coagulation and liver function, including a low
platelet count, prolonged prothrombin
time, an increased international normalized ratio, increased gamma glutamil
transferase, and increased aspartate
amino transferase (Table).
A clinical examination revealed
movement disorders, dystonia, tremors,
and a Kayser-Fleischer ring (Fig. 1).
Discussion
As stated previously, patients with WD
may exhibit clinical manifestations,
such as liver disease and neurological
impairment. Laboratory tests measuring
hemostatic disorders should be considered during dental care. In the present
case report, the patient had signs and
symptoms of neurologic impairment and
end-stage liver disease with important
coagulation abnormalities.
www.agd.org
Neurological impairment—including
orthostatic hypotension and an altered gag
reflex—needs to be considered during the
dental treatment of a WD patient. Dental
professionals must always be aware of
these potential complications and keep the
dental chair in a vertical position during
the dental treatment to reduce the likelihood of a fall when the patient rises. This
precaution also prevents aspiration of water
or materials used during dental procedures.8 All dental procedures in the present
case were performed with the dental chair
in a vertical position.
Patients with WD have difficulty maintaining oral hygiene due to their physical
disability. Some drugs (such as antimuscarinic or antiparkinsonian agents) can
reduce salivation, potentially increasing
the incidence of caries.8 The patient in the
present case had some carious lesions but
had not reported symptoms of xerostomia.
He had not been prescribed drugs to control his nervous system; however, he had
severe motor impairment that affected his
oral hygiene, potentially causing caries.
Lohe et al conducted a literature review
of clinical aspects related to Wilson’s
disease and the impact of WD on dental
management.8 The authors stressed
that when patients have a tendency to
bleed, dentists should confirm WD
with various tests—such as complete
blood counts, coagulations studies, and
liver and kidney functions tests—before
General Dentistry
May/June 2015
65
Dentistry for the Medically Compromised Dental management of a patient with Wilson’s disease
performing any surgical or periodontal
procedures. Furthermore, the authors
emphasized the need to avoid drugs
metabolized by the liver and noted that
a WD patient must be treated in the
upright position to avoid alteration of the
gag reflex and the aspiration of water or
materials used during dental procedures.8
Although patients with WD may
develop oral complications due to the
disease, there may be other complications
associated with prolonged therapy. Tovaru
et al described 2 patients with multiple
small red papules of the lips, gingival
enlargement, early-onset periodontitis,
and repeated oral candidiasis associated
with D-penicillamine, a drug used to treat
WD.9 The patient in the present case
did not show these oral manifestations,
which may be due to shorter periods of
D-penicillamine treatment as compared to
the cases described by Tovaru et al.
In terms of dental management, bleeding disorders are the greatest concern
for patients with end-stage liver disease.
Routine dental procedures (such as SRP
and tooth extractions) can result in serious
complications in these patients if the dentist
is unaware of the risks of impaired hemostasis and increased bleeding. For patients
with hemostatic impairment, surgical
techniques and successive sessions of SRP
should be used, including local hemostatic
measures and primary wound closure.10,11
Although the patient in the present case
showed abnormal coagulation values, he
did not exhibit critical values that would
contraindicate invasive dental treatment.
66
May/June 2015
General Dentistry
For this reason, the dental treatments were
conducted in an outpatient clinic. Dental
extraction and periodontal treatment were
conducted using local hemostatic measures,
particularly a tranexamic acid paste and
absorbable gelatin sterile sponges.10,11
Providing oral health care before and
after liver transplantation is essential for
establishing a good prognosis and quality of life in transplant recipients. Before
transplantation, the main concern is to
eliminate the oral foci of infection, including those of periapical and periodontal origins.12 The treatment plan in the present
case focused on restorative and periodontal
treatment with an emphasis on prevention,
orientation, and education to maintain
the patient’s oral health while respecting
the limits of his clinical condition and the
laboratory parameters of coagulation.
Conclusion
Patients with WD and end-stage liver failure require judicious, special dental care
to eliminate the oral foci of infection and
to control oral disease prior to transplantation with minimal risk of complications
to the patient.
Author information
Dr. da Silva Santos is a full professor,
Dr. Fernandes is a postdoctoral researcher,
and Dr. Gallottini is a full professor and
chair, Department of Stomatology, School
of Dentistry, University of Sao Paulo,
Bauru, Brazil. Dr. Gallottini is also
head of Special Care Dentistry, where
Dr. Fraige is a dentist.
www.agd.org
References
1. Compston A. Progressive lenticular degeneration: a
familial nervous disease associated with cirrhosis of
the liver, by S. A. Kinnier Wilson (From the National
Hospital and the Laboratory of the National Hospital,
Queen Square, London). Brain. 1912;34:295-509.
Brain. 2009;132(Pt 8):1997-2001.
2. Yamaguchi Y, Aoki T, Arashima S, et al. Mass screening
for Wilson’s disease: results and recommendations.
Pediatr Int. 1999;41(4):405-408.
3. Brewer GJ, Askari FK. Wilson’s disease: clinical management and therapy. J Hepatol. 2005;42(Suppl 1):
S13-S21.
4. Tanzi RE, Petrukhin K, Chernov I, et al. The Wilson disease gene is a copper transporting ATPase with homology to the Menkes disease gene. Nat Genet. 1993;
5(4):344-350.
5. Yamaguchi Y, Heiny ME, Gitlin JD. Isolation and characterization of a human liver cDNA as a candidate
gene for Wilson disease. Biochem Biophys Res Commun. 1993;197(1):271-277.
6. El-Youssef M. Wilson disease. Mayo Clin Proc. 2003;
78(9):1126-1136.
7. Ferenci P. Pathophysiology and clinical features of
Wilson disease. Metab Brain Dis. 2004;19(3-4):
229-239.
8. Lohe VK, Kadu RP, Degwekar SS, Bhowate RR, Wanjari
AK, Dangore SB. Dental considerations in the patient
with Wilson’s disease. Oral Surg Oral Med Oral Pathol
Oral Radiol Endod. 2011;111(1):20-23.
9. Tovaru S, Parlatescu I, Dumitriu AS, Bucur A, Kaplan I.
Oral complications associated with D-penicillamine
treatment for Wilson disease: a clinicopathologic report. J Periodontol. 2010;81(8):1231-1236.
10. Rada RE. Management of the dental patient on anticoagulant medication. Dent Today. 2006;25(8):5863.
11. Ramstrom G, Sindet-Pedersen S, Hall G, Blomback M,
Alander U. Prevention of postsurgical bleeding in oral
surgery using tranexamic acid without dose modification of oral anticoagulants. J Oral Maxillofac Surg.
1993;51(11):1211-1216.
12. Wakefield CW, Throndson RR, Brock T. Liver transplantation: dentistry is an essential part of the team. J Tenn
Dent Assoc. 1995;75(3):9-16.
Root Caries & Treatment
Endodontic treatment of mandibular molars with
atypical root canal anatomy: reports of 4 cases
Raju Chauhan, BDS, MDS n Shweta Singh, BDS, MDS
The variations in root canal anatomy of multirooted teeth represent a
continuous challenge to endodontic diagnosis and treatment. Although
the most common configuration of mandibular molars is one containing 2 roots and 3 root canals, there are many different combinations.
Very rarely, an additional third (supernumerary) root is seen. When it
is located distolingually to the main distal root, this third root is called
radix entomolaris (RE), and when it is located mesiobuccally to the
mesial root, it is called radix paramolaris (RP). Variations of root canal
systems need not always be in the form of extra roots or extra canals.
Single roots with single canals can also occur. A general dentist should
be aware of these unusual root canal morphologies in mandibular molars
T
he main objectives of root canal therapy are the thorough debridement of
the entire pulp space, 3-dimensional
obturation with an inert material, and
placement of a coronal filling that prevents
the ingress of microorganisms.1 Two of the
main factors associated with endodontic
failure are the persistence of microbial
infection in the root canal system and the
complexity of root canal anatomy.2 The
clinician must have an in-depth knowledge
of root canal anatomy and be aware of
its anatomic variations—including extra
roots and/or extra canals—which may
complicate an endodontic procedure.3 The
mandibular molars typically present with 2
well-defined roots: a mesial root characterized by a flattened mesiodistal surface and
widened buccolingual surface, and a distal
root that is mostly straight with a wide
A
B
for the success of endodontic treatment. These case reports describe
the root canal treatment of a case of RE in the mandibular first molar,
2 rare cases of RP (1 each in the mandibular first and second molars),
and a mandibular second molar with a single root and root canal.
Received: December 16, 2013
Revised: May 27, 2014
Accepted: June 5, 2014
Key words: mandibular first molar, mandibular second molar,
radix entomolaris, radix paramolaris, single root
oval canal or 2 round canals.4 An important variation found in mandibular molars
is the existence of a third root. If this extra
root is present on the distolingual side, it
is termed radix entomolaris (RE).5 If this
extra root is present on the mesiobuccal
side, it is termed radix paramolaris (RP).6
The presence of an RE in the mandibular first molar is associated with certain
ethnic groups.7 According to various
studies, the prevalences of an RE in the
mandibular first molar are 22.3% in
Koreans, 3.9% in Jordanians, 3.1% in
Africans, 0.7% in Germans, and 2.2% in
Caucasians.4,8-11 The presence of an RP is
very rare in both European and Mongolian
populations.12,13 In a study conducted by
Visser, the incidence of RP was 0%, 0.5%,
and 2.0% for the mandibular first, second,
and third molars, respectively.13 However,
C
other studies have reported RP in mandibular first molars.6,14
The most important root canal variation in the mandibular second molar is a
C-shaped anatomy. Both the mesial and
distal roots can be fused to form a single
conical root with varying internal anatomy, often resulting in a C-shaped canal
configuration.15 In a study of 75 human
extracted second molars, Weine et al found
1 tooth with 1 root canal (1.3%).16 A
study conducted by Rahimi et al on 139
extracted mandibular second molars in an
Iranian population found 8 (5.7%) teeth
had single roots and/or canals.17
The following case reports describe the
endodontic management of RE in a mandibular first molar, RP in mandibular first
and second molars, and a single-rooted
mandibular second molar.
D
Fig. 1. Case No. 1. A. Preoperative radiograph showing radix entomolaris (RE) in tooth No. 19. B. Working length radiograph that revealed the presence of RE. C.
Master cone radiograph. D. Postoperative radiograph with obturated canals.
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Root Caries & Treatment Endodontic treatment of mandibular molars with atypical root canal anatomy: reports of 4 cases
A
B
C
D
Fig. 2. Case No. 2. A. Preoperative radiograph showing the presence of 2 separate roots mesially diagnosed as radix paramolaris (RP) in tooth No. 19 (arrows).
B. Working length radiograph confirming RP. C. Master cone radiograph. D. Postoperative radiograph.
Case No. 1
A 29-year-old man presented with an
extensive distal carious lesion in the mandibular left first molar. The patient also
complained of dull pain from the tooth. No
periodontal pockets were present. Clinical
examination of the surrounding teeth did
not reveal any clinical signs or symptoms.
A radiograph of the involved tooth revealed
deep distal caries in tooth No. 19 with no
periapical changes. The tooth was not sensitive to percussion but responded negatively
to sensibility testing (cold testing and
electrical pulp vitality testing). Based on
the findings, the tooth was diagnosed with
chronic irreversible pulpitis.
Examination of the preoperative radiograph revealed the presence of 3 roots in
tooth No. 19 (Fig. 1A). The extra root
was an RE. Nonsurgical endodontic treatment was planned in tooth No. 19. The
tooth was anesthetized and accessed under
rubber dam isolation. The access opening
was modified into a more trapezoidal form
in order to locate and open the orifice of
the RE. Initially, 2 mesial canal orifices
and 1 distal canal orifice were located. In
addition, a dark line led to the RE. The
root canals were explored with a precurved
K-file No. 15 (DENTSPLY Maillefer),
and the radiographic length measurement
was established (Fig. 1B). The canals were
cleaned and shaped in a crown-down
manner with nickel-titanium rotary files
(ProTapers, DENTSPLY Maillefer), while
they were copiously irrigated with 5%
sodium hypochlorite and 17% ethylenediaminetetraacetic acid (EDTA). A master
cone radiograph was also taken with corresponding ProTaper gutta percha cones
(Fig. 1C). Obturation of the root canals
68
May/June 2015
General Dentistry
was performed using gutta percha and AH
Plus sealer (DENTSPLY Maillefer) with a
cold lateral condensation technique. The
access cavity was restored with restorative
composite resin, and a radiograph was
taken to confirm the quality of the obturation (Fig. 1D).
obturated with a cold lateral condensation
technique using AH Plus sealer and gutta
percha cones. The access was restored with
composite restorative resin. A postoperative
radiograph was taken to confirm the quality of the obturation (Fig. 2D).
Case No. 2
A 25-year-old man reported with an
inability to chew with his mandibular right
second molar for the previous few days.
Clinical examination found deep occlusal
caries in the molar. A periapical radiograph
of tooth No. 31 confirmed deep occlusal caries with no associated periapical
pathosis (Fig. 3A). The tooth responded
abnormally to pulp testing, leading to a
diagnosis of acute irreversible pulpitis.
The tooth was anaesthetized and
accessed under rubber dam isolation. Hand
K-files (DENTSPLY Maillefer) were used
to locate a distal and a mesial canal orifice.
Further exploration on the mesiobuccal
side was done to locate a third canal, thus
identified as an RP. A working length
radiograph (K-file No. 15) confirmed the
presence of RP (Fig. 3B). Instrumentation
was completed in all the canals with
ProTapers, using 5% sodium hypochlorite
and 17% EDTA. A master cone radiograph
was taken (Fig. 3C). Canals were obturated
with gutta percha and AH Plus sealer. The
tooth was restored with an amalgam restoration, and a final radiograph was taken
postoperatively (Fig. 3D).
A 24-year-old woman with a noncontributory medical history reported with
a chief complaint of pain and sensitivity
in her lower left posterior teeth. Intraoral
examination revealed the presence of a
deep carious lesion in the left mandibular
first molar. A radiograph was taken, revealing deep occlusal caries and condensing
osteitis in tooth No. 19 (Fig. 2A). Vitality
tests (cold and electrical pulp tests) on the
involved tooth showed abnormal responses,
indicating that irreversible pulpitis had
occurred. A periapical radiograph revealed
2 periodontal ligament outlines in the
mesial root, indicating the presence of RP.
The tooth was anaesthetized and accessed
under rubber dam isolation. Initially,
2 distal canals and 1 mesial canal were
located. A fourth canal was located when
further cutting was done on the mesiobuccal side; thus it was identified as an RP. All
the canals were instrumented with precurved K-file No. 15, and a working length
radiograph was taken (Fig. 2B). The working length radiograph confirmed the presence of an RP. Cleaning and shaping in all
the canals was accomplished with a crowndown technique using ProTapers. During
cleaning and shaping, the canals were
irrigated with 5% sodium hypochlorite and
17% EDTA. A radiograph was taken with
the master cone (Fig. 2C). The canals were
www.agd.org
Case No. 3
Case No. 4
A 38-year-old man was referred for
endodontic treatment. The patient complained of pain in relation to the right
mandibular posterior region, especially
A
B
C
D
Fig. 3. Case No. 3. A. Preoperative radiograph indicating the presence of RP in tooth No. 31. B. Working length radiograph confirming the existence of RP. C. Master
cone radiograph showing the outlines of 2 roots mesially. D. Postoperative radiograph following the obturation of RP.
A
B
C
Fig. 4. Case No. 4. A. Preoperative radiograph of tooth No. 31 showing the existence of a single root. B. Working length radiograph confirming the
presence of a single large canal. C. Postoperative radiograph with obturated canal.
after consuming hot drinks. Intraoral
examination revealed deep caries in tooth
No. 31. An intraoral periapical radiograph
revealed deep caries approximating the
pulp without any associated periapical
changes (Fig. 4A). The tooth responded
abnormally to pulp testing. Based on
the findings, the tooth was diagnosed as
having irreversible pulpitis. A detailed
examination of the radiograph revealed
the presence of a single root with a wide
canal. Therefore, a C-shaped canal configuration was anticipated.
After anesthesia, the access cavity was
opened under a rubber dam, and the
pulp was extirpated. Examination of the
pulpal floor revealed a single round-shaped
orifice, a classical C-shaped canal orifice
configuration. No other canal orifices
could be located. The working length was
determined radiographically with a K-file
No. 30 (DENTSPLY Maillefer) (Fig. 4B).
Cleaning and shaping was completed by
the step-back method along with a combination of irrigants. A snug-fitting master
cone was selected. Obturation of the
canal was done by a combination of warm
vertical condensation and a thermoplasticized injectable gutta percha technique
(E & Q Plus, META-BIOMED Co.,
Ltd.). The access cavity was sealed with an
amalgam restoration, and a radiograph was
taken (Fig. 4C).
Discussion
Clinicians must have thorough knowledge
of root canal anatomy and the morphology of the pulp chamber before initiating
endodontic treatment on a patient. All
root canals should be identified, cleaned,
and shaped to receive a hermetic filling
of the entire root canal space. Incomplete
cleaning, shaping, and obturation of any
root canal will lead to almost certain endodontic failure.
Over the years, there have been numerous studies that described the morphologies of various teeth, including mandibular
molars.1 The major variant in this group
is the mandibular first molar with 3 roots.
The additional root is usually located on
the lingual aspect.10 This type of root canal
anatomy occurs less frequently in mandibular second molars, but these teeth have a
www.agd.org
high incidence of C-shaped root canals.15
A general dentist needs to be aware of the
the high frequency of variation found in
the morphologies of mandibular molars.
An RE is located on the distolingual side
of the tooth, with its coronal third completely or partially fixed to the distal root in
the form of a short conical extension to a
mature root with a normal length and root
canal. In general, the RE is smaller than
the distobuccal and mesial roots and can be
separate from—or partially fused with—
the other roots.18 An RP is located on the
mesiobuccal side of the tooth. As with
an RE, the dimensions of an RP can vary
from a mature root with a root canal to a
short conical extension. This additional
root can also be separate or nonseparate.6
An accurate diagnosis of these supernumerary roots can avoid complications or a
missed canal during root canal treatment.
A thorough inspection of the preoperative
radiograph and interpretation of particular
marks or characteristics, such as an unclear
view or outline of the distal/mesial root
contour or the root canal, can indicate the
presence of a hidden RE and/or RP.18 With
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Root Caries & Treatment Endodontic treatment of mandibular molars with atypical root canal anatomy: reports of 4 cases
RE and RP, the conventional triangular
access cavity must be modified to a more
trapezoidal or rectangular form to better
locate and access the additional orifice of
the extra root.18,19 Calberson et al recommended using flexible nickel-titanium
rotary files to allow a more centered preparation and restricted enlargement of the
coronal third of the root canal.18 In a 2009
study of permanent 3-rooted mandibular
first molars conducted by Tu et al, the
mean interorifice distances from the distolingual canal to the distobuccal, mesiobuccal, and mesiolingual canals of the molars
were 2.7, 4.4, and 3.5 mm, respectively.20
These values can help dentists to locate
orifices and to achieve successful endodontic treatment of RE.
In Cases No. 1-3, RE and RP were
diagnosed in the preoperative radiographs
along with the working length and master
cone radiographs. The access cavities were
then modified to more trapezoidal forms
to locate the orifices of the extra roots
and canals. Cleaning and shaping was
accomplished with nickel-titanium rotary
instruments in combination with irrigants in order to limit procedural errors.
Subsequently, the canals were obturated
with a cold lateral condensation technique.
Another important variation which
frequently occurs in the mandibular second
molar is a C-shaped root and/or canal. This
variation may also occur in mandibular first
molars, maxillary molars, mandibular first
premolars, and even in maxillary lateral
incisors.15 Typically, this canal configuration is found in teeth with fusions of the
roots either on the buccal or lingual aspects.
The main anatomic feature of C-shaped
canals is the presence of a fin or web connecting the individual root canals.21
The morphologic C-shaped canal variation is unusual and can lead to difficulties
during treatment, so proper diagnosis of
this situation is mandatory before treatment. A preoperative radiograph and an
additional radiograph from a 20 degree
mesial or distal projection may provide
clues about the canal morphology.22 The
root configuration of molars having this
canal shape may be represented as a single
fused root or as 2 distinct roots with a communication. Clinically, this anatomy can be
diagnosed by gaining access and observing
the pulp chamber. The clinician may find a
large occlusogingival pulp chamber, a single
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General Dentistry
large canal orifice, or multiple orifices
that are interconnected. The prevalence of
single-rooted and single-canal mandibular
second molars ranged from 1.3% to 8.0%
in previous studies.16,17,23
In Case 4, after access cavity preparation, only 1 canal with a round orifice was
located, suggesting the presence of a single
canal. Further exploration of the pulpal
floor did not reveal the presence of any
additional orifice opening. Biomechanical
preparation and copious irrigation were
done to ensure complete removal of debris.
The canal was obturated using thermoplasticized gutta percha with a master cone
to prevent extrusion beyond the apex.
The advantage of using a thermoplastized
injectable obturating technique is that it
ensures compact obturation of wide canals
without voids and obturation of any aberration present in these canal systems.
Conclusion
A general dentist should be aware of the
morphological variations in mandibular
molars, such as additional roots, additional canals, and C-shaped canals. The
morphological variations of RE and RP in
terms of root inclination and root canal
curvature demand careful, adapted, clinical approaches to avoid procedural errors
during endodontic therapy. The initial
diagnosis of RE, RP, or C-shaped canals
prior to endodontic treatment is important
to facilitate procedures during treatment
and avoid the mislocation of any canal.
Periapical radiographs executed in the preoperatory stage with different horizontal
angulation help to identify these anatomic
variations. Management of such cases
requires the judicial application of diagnostic tools and endodontic skills.
Author information
Dr. Chauhan is a reader, Department of
Conservative Dentistry and Endodontics,
Saraswati Dental College and Hospital,
Lucknow, India, where Dr. Singh is
a lecturer, Department of Oral and
Maxillofacial Pathology.
References
1. Vertucci FJ. Root canal morphology and its relationship
to endodontic procedures. Endod Topics. 2005;10:3-29.
2. Nair PN. On the causes of persistent apical periodontitis: a review. Int Endod J. 2006;39:249-281.
3. Plotino G. A mandibular third molar with three mesial
roots: a case report. J Endod. 2008;34(2):224-226.
www.agd.org
4. Skidmore AE, Bjorndal AM. Root canal morphology of
the human mandibular first molar. Oral Surg Oral Med
Oral Pathol. 1971;32(5):778-784.
5. Carabelli G. Systematisches Handbuch der Zahnheikunde. 2nd ed. Vol. 114. Vienna: Braumuller and Seidel; 1844.
6. Carlsen O, Alexandersen V. Radix paramolaris in permanent mandibular molars: identification and morphology. Scand J Dent Res. 1991;99(3):189-195.
7. de Pablo OV, Estevez R, Peix Sanchez M, Heilborn C,
Cohenca N. Root anatomy and canal configuration of
the permanent mandibular first molar: a systematic
review. J Endod. 2010;36(12):1919-1931.
8. Park JB, Kim N, Park S, Kim Y, Ko Y. Evaluation of root
anatomy of permanent mandibular premolars and molars in a Korean population with cone-beam computed
tomography. Eur J Dent. 2013;7:94-101.
9. Al-Qudah AA, Awawdeh LA. Root and canal morphology of mandibular first and second molar teeth in a Jordanian population. Int Endod J. 2009;42(9):775-784.
10. Sperber GH, Moreau JL. Study of the number of roots
and canals in Senegalese first permanent mandibular
molars. Int Endod J. 1998;31(2):117-122.
11. Schafer E, Breuer D, Janzen S. The prevalence of threerooted mandibular permanent first molars in a German population. J Endod. 2009;35(2):202-205.
12. Ballulaya SV, Vemuri S, Kumar PR. Variable permanent
mandibular first molar. Review of literature. J Conserv
Dent. 2013;16(2):99-110.
13. Visser JB. Beitrag zur Kenntnis der menschlichen Zahnwurzelformen. Hilversum: Rotting 1948;4972.
14. Yew SC, Chan K. A retrospective study of endodontically treated mandibular first molars in a Chinese population. J Endod. 1993;19(9):471-473.
15. Jafarzadeh H, Wu YN. The C-shaped root canal configuration: a review. J Endod. 2007;33(5):517-523.
16. Weine FS, Pasiewicz RA, Rice RT. Canal configuration
of the mandibular second molar using a clinically oriented in vitro method. J Endod. 1988;14(5):207-213.
17. Rahimi S, Shahi S, Lotfi M, Zand V, Abdolrahimi M,
Es’haghi R. Root canal configuration and prevalence
of C-shaped canals in mandibular second molars in an
Iranian population. J Oral Sci. 2008;50(1):9-13.
18. Calberson FL, De Moor RJ, Deroose CA. The radix entomolaris and paramolaris: clinical approach in endodontics. J Endod. 2007;33(1):58-63.
19. De Moor RJ, Deroose CA, Calberson FL. The radix entomolaris in mandibular first molars: an endodontic
challenge. Int Endod J. 2004;37(11):789-799.
20. Tu MG, Huang HL, Hsue SS, et al. Detection of permanent three-rooted mandibular first molars by cone
beam computed tomography imaging in Taiwanese
individuals. J Endod. 2009;35(4):503-507.
21. Fan B, Cheung GS, Fan M, Gutmann JL, Bian Z. Cshaped canal system in mandibular second molars, I:
Anatomical features. J Endod. 2004;30(12):899-903.
22. De Moor RJ. C-shaped root canal configuration in maxillary first molars. Int Endod J. 2002;35(2):200-208.
23. Cimilli H, Cimilli T, Mumcu G, Kartal N, Wesselink P.
Spiral computed tomographic demonstration of Cshaped canals in mandibular second molars. Dentomaxillofac Radiol. 2005;34(3):164-167.
Manufacturers
DENTSPLY Maillefer, Tulsa, OK
800.924.7393, www.maillefer.com
META-BIOMED Co., Ltd., Chalfont, PA
267.282.5893, www.meta-biomed.com
Practice Management & Human Relations
Hearing loss associated with long-term exposure
to high-speed dental handpieces
Sarah M. Theodoroff, PhD n Robert L. Folmer, PhD
The purpose of this study was to record and compare audiometric pure
tone thresholds of dental clinicians (DCs), dental professionals (DPs),
and dental students (DSs); determine the percentage of these groups
who use hearing protection devices while at work in the clinic; and
measure the sound intensities generated by a few representative highspeed handpieces while they are being used on patients. Participants
included DCs who regularly used these handpieces (n = 16), DPs who
did not use these handpieces (n = 13), and DSs (n = 8). A questionnaire
was used to collect demographic information, assess occupational and
recreational noise exposure, and note the level of hearing protection
used. A sound level meter was used to measure the sound intensity
T
he cause-and-effect association
between loud noise exposure and
hearing loss is well established.1 The
National Institute on Deafness and Other
Communication Disorders website reports
that approximately 15% of Americans
between the ages of 20 and 69—26 million Americans—have high-frequency
hearing loss that may have been caused
by exposure to loud noises at work or
in leisure activities.2 In an attempt to
reduce workers’ risk of developing noiseinduced hearing loss (NIHL), the United
States Occupational Safety and Health
Administration (OSHA) established safety
standards related to noise exposure.3
Originally published in 1983, the standard states that the maximum permissible
exposure limit (PEL) in an 8-hour day
should not exceed 90 dBA SPL (decibel
sound pressure level using an A-weighted
scale).3 OSHA’s standard uses a 5 dB
exchange rate, meaning that the PEL for
95 dB noise is reduced to 4 hours, the
PEL for 100 dB sound is 2 hours, and so
on. However, these standards are applied
to large populations of people. Within
these populations, some individuals are
more susceptible to noise-induced auditory dysfunction than others.
Sound intensity generated by
high-speed dental handpieces
It has been suspected for decades that
high-speed handpieces might contribute to
the hearing loss exhibited by some dental
generated by dental instruments near a clinician’s ear. Results showed
that DCs who regularly used high-speed handpieces had worse hearing
than did members of the other study groups. These results indicate that
the implementation of protective strategies should help to reduce the
prevalence of occupational hearing loss among DCs.
Reviewed: July 23, 2013
Revised: October 22, 2013
Accepted: November 14, 2013
Key words: noise-induced hearing loss, highspeed handpieces, hearing protection
clinicians (DCs). Consequently, several
investigators have measured the sound
intensities generated by these devices.4-8
Barek et al analyzed the sound intensities
generated by high-speed handpieces in
both the audible (<20,000 Hz) and ultrasonic (>20,000 Hz) frequency ranges.4 The
authors reported that the MICRO-MEGA
brand handpiece (MICRO-MEGA SA)
generated a maximum of 95 dB SPL
in the audible range, but 112 dB SPL
at 50,000 Hz. The Siemens (Siemens
Corporation) and KaVo (KaVo Dental)
brand handpieces generated high intensity
sounds (101 and 115 dB SPL, respectively)
in the ultrasonic frequency range. Barek
et al concluded that all these instruments
“reach levels that may provoke short- or
long-term negative physiological disturbances and hearing damage risk.”4
Kilpatrick listed the sound intensities
generated by high-speed handpieces
(70-92 dB SPL), ultrasonic scalers (86
dB SPL), stone mixers (84 dB SPL), and
low-speed handpieces (74 dB SPL).5
Sorainen & Rytkonen reported that the
A-weighted sound pressure level generated by a variety of handpieces ranged
from 76 to 89 dB SPL.6 In Portugal,
Sampaio Fernandes et al measured sound
levels in different areas of a dental school
and reported intensities ranging from
60 to 99 dB SPL.7 Kadanakuppe et al
recorded a strikingly similar range of
sound levels (64-97 dB SPL) at a dental
school in India.8
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A key question is whether or not these
reported sound intensities can cause hearing loss. The physiological effects of sound
on hearing depend on both the intensity
of sound and the duration of exposure.2,3
Because dental professionals (DPs) do not
use high-speed handpieces or other instruments continuously during the workday,
they do not usually exceed OSHA’s PEL
or the more conservative PEL (85 dB)
recommended by the National Institute for
Occupational Safety and Health.3,9 While
considering these recommendations, it
is important to remember that Park cautioned, “There is a danger, however, of finding comfort in the results of group studies
and group standards. Every group is made
of individuals, and individuals react to
different things in different ways at different times.”10 Merrell & Claggett expressed
similar sentiments: “Ears differ in their
susceptibility to damage through exposure
to noise, thus exposure in a common work
environment may cause hearing loss in one
person and not in another.”11 Since most
people do not know their personal susceptibility to loud noise exposure, Park—along
with Merrell & Claggett and others—
recommended that DPs implement strategies in the workplace to reduce their risk
of occupational hearing loss.10,11
Evidence of noise-induced hearing
loss among dental professionals
More than 12 published studies have
assessed the hearing of DCs to determine
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May/June 2015
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Practice Management & Human Relations Hearing loss associated with long-term exposure to high-speed dental handpieces
if they have significantly worse hearing
compared to age-matched individuals who
are not regularly exposed to the noise generated by high-speed dental handpieces.
One of the early studies was conducted in
Scotland by Taylor et al.12 These authors
tested the hearing of 30 dentists who used
air turbine drills in their practices. The
researchers concluded that the dentists
exhibited elevated auditory thresholds at
4000 and 6000 Hz, which is a characteristic of noise-induced hearing loss.
Zubick et al compared the pure tone
hearing thresholds of 11 dentists (average
age 48 years) with those obtained from 80
physicians (average age 45 years).13 The
authors found that the auditory thresholds
for the dentists were slightly worse than
the physicians’ thresholds at 4000 and
6000 Hz. They concluded that “there may
be a cause and effect relationship between
hearing loss and use of the high-speed
dental handpiece.”13
Wilson et al tested the hearing of 20
dental hygienists (mean age 43 years) who
often used ultrasonic scalers and 20 dental
hygienists who seldom used ultrasonic
scalers (mean age 43 years).14 Their results
indicated that the high-usage group had
significantly worse thresholds for 3000 Hz
tones compared to the low-usage group.
Again, because elevated thresholds at 3000
Hz can indicate excessive exposure to
loud sounds, it is possible that the noise
generated by ultrasonic scalers contributed
to the occupational hearing loss exhibited
by these hygienists. Evidence of greater
than expected hearing loss in DCs has
also been reported by Fabry, Gijbels et
al, Bali et al, and Messano & Petti.15-18
However, other researchers who tested
the hearing of DCs concluded that
noise generated in the clinic did not
contribute to additional hearing loss.19-21
Obviously, controversy exists regarding the
contributions of high-speed handpieces
to NIHL in DCs. Attributing specific
sources of noise exposure to hearing loss
in adults is often difficult because of the
many factors that contribute to auditory
dysfunction: age, genetics, disease, and
other sources of loud sound exposure.
Each person’s individual susceptibility to
hearing loss from noise exposure should
be considered when decisions are made
regarding the implementation of hearing
protection strategies in the workplace.
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May/June 2015
General Dentistry
Table 1. Descriptive statistics of the study groups.
Group
n
Mean age in
years (SD)
Gender (n)
Average number of years
(SD) in profession
Dental clinicians
16
53.5 (12.0)
M (16), F (0)
22.3 (12.3)
Dental professionals
13
47.3 (11.5)
M (4 ), F (9)
21.8 (11.1)
Dental students
8
28.9 (3.4)
M (5), F (3)
2.8 (0.4)
Abbreviations: F, female; M, male; n, number; SD, standard deviation.
Use of hearing protection devices
by dental clinicians
In 1974, the American Dental Association
(ADA) Council on Dental Materials and
Devices issued the report, Noise Control
in the Dental Operatory.22 The Council
recommended that preventive measures
for noise attenuation should include
“personal protection through the use of
ear plugs.” 22 Before and after publication
of this report, many researchers and
clinicians recommended that DCs utilize
hearing protection devices (HPDs) when
using noisy equipment or instruments
in the clinic or laboratory.6,10,11,14,15,23-30
Although the recommendation that
DCs utilize HPDs while using noisy
instruments has been made repeatedly
during the last 4 decades, few studies of
HPD implementation among them have
been conducted. Serafini et al reported
that only 1 of the 23 dentists in their
study used HPDs at work.29
Current investigation
This pilot study was undertaken to
record and compare audiometric pure
tone thresholds of DCs, DPs, and dental
students (DSs); determine the percentage
of DCs, DPs, and DSs who use hearing
protection devices while at work in the
clinic; collect data from DCs, DPs, and
DSs regarding nonoccupational noise
exposure; and measure the sound intensities generated by a few representative
high-speed handpieces while they are
being used on patients.
Materials and methods
Study participants were recruited and
data were collected at the Oregon Health
& Science University (OHSU) Dental
School. Participants included DCs who
regularly used high-speed handpieces
www.agd.org
(n = 16), DPs who did not use high-speed
handpieces (n = 13), and DSs (n = 8).
Pure tone audiometric data were collected
at 500, 1000, 2000, 3000, 4000, 6000,
and 8000 Hz using a portable audiometer
(Beltone model 119, Beltone) in a quiet
room. A portable audiometer was used in
order to make testing more convenient for
the dental school faculty, staff, and students. Audiometric thresholds were later
verified by retesting a subset of research
subjects in a clinical sound booth. A questionnaire was used to assess occupational
and recreational noise exposure, note any
use of hearing protection, and collect
demographic information. A Bruel &
Kjaer Type 2250 sound level meter (Bruel
& Kjaer Sound & Vibration Measurement
A/S) was used to measure the sound
intensity generated by dental instruments near each clinician’s ear. Informed
consent was obtained before any measurements or tests were performed. All
research procedures were approved by
the OHSU Institutional Review Board.
Written informed consent was obtained
from all study participants.
Results
Participants
Table 1 shows descriptive statistics for
each of the study groups. The noiseexposed DC group included 15 dentists
and 1 prosthodontist. The minimal noise
exposure DP group included radiologists,
radiology technicians, and clinic administrators. The third group comprised
DSs. A 2-tailed t test revealed no statistically significant differences between the
mean ages of the noise-exposed DCs
compared to the DPs with minimal noise
exposure (P > 0.05). The DSs were significantly younger than the members of
the other groups.
Chart. Mean audiometric data for each group in the study.
Table 2. Analysis of variance
comparing audiometric thresholds
across test frequencies.
0
5
Frequency
Intensity (dB HL)
10
15
20
25
30
35
40
45
DCs
RE LE
DPs
RE LE
DSs
RE LE
500 1000
2000
3000
4000
Frequency (Hz)
6000
8000
Abbreviations: DCs, dental clinicians who routinely use high-speed handpieces (n=16); DPs, dental professionals
who do not use high-speed handpieces (n=13); DSs, dental students (n=8); LE, left ear; RE, right ear.
*Thresholds at these frequencies were significantly worse in the DC group than in the DP and DS groups
(see Tables 2 and 3 for details).
Audiometric results
The averaged audiograms for each
study group are shown in the Chart.
Audiometric thresholds collected via
portable audiometer were verified by
retesting a subset of 12 research subjects
in a clinical sound booth. This verification
process revealed that thresholds collected
using the 2 methods agreed within 5 dB
for all test frequencies, which is within
the clinical standard of error for pure
tone hearing sensitivity tests. The mean
audiometric results for the group of
noise-exposed DCs revealed a sloping
high-frequency hearing loss. The group
of DPs with minimal noise exposure had
hearing thresholds within the normal
range of hearing, but their thresholds were
poorer compared to the DSs. A 1-way
ANOVA and a Bonferroni correction for
multiple comparisons showed a significant
difference (P < 0.05) among the mean
thresholds of the 3 groups (for both ears)
from 3000 to 8000 Hz (Table 2). Post hoc
testing revealed that the mean thresholds
of the DC group were significantly worse
compared to the DP and the DS groups
for 4000 to 8000 Hz in the right ear
and approached statistical significance
at 3000 Hz (P = 0.055 compared to
the DP group; P = 0.058 compared to
the DS group). Left ear data revealed
significant differences from 3000 to
6000 Hz between the DCs and DSs, and
significant differences between the DC
group and the other 2 groups at 8000 Hz
(Table 3). Audiometric mean thresholds
for the DP group were not significantly
different from the DS group in either ear.
Hearing protection device use
The use of HPDs in the OHSU dental
clinics was rare, with only 1 of 16 DCs,
0 of 13 DPs, and 1 of 8 students reporting
that they used earplugs in the workplace.
Nonoccupational noise exposure
In addition to work-related noise exposure (such as high-speed handpieces,
suction devices, or ultrasonic scalers),
many study participants also reported
histories of significant exposure to loud
sounds outside of the dental clinic. For
example, several noise-exposed clinicians and other DPs served in the US
military and were exposed to extremely
www.agd.org
F
P value
RE 500 Hz
1.728
0.193
RE 1000 Hz
2.804
0.075
RE 2000 Hz
2.598
0.089
RE 3000 Hz
4.390
0.020*
RE 4000 Hz
4.807
0.015*
RE 6000 Hz
8.497
0.001*
RE 8000 Hz
8.313
0.001*
LE 500 Hz
2.148
0.132
LE 1000 Hz
3.103
0.058
LE 2000 Hz
2.292
0.116
LE 3000 Hz
3.993
0.028*
LE 4000 Hz
4.000
0.028*
LE 6000 Hz
4.351
0.021*
LE 8000 Hz
4.810
0.014*
*Designates clinical significance ( P < 0.05).
Abbreviations: RE, right ear; LE, left ear.
loud sounds—gunfire, artillery fire, and
explosions—during training or combat.
Some study participants also reported
being exposed to recreational gunfire,
fireworks, loud sounds from power tools,
music, factory machinery, or farm equipment. Participants reported that they
“sometimes” or “never” wore HPDs during
these activities. None of the participants
“always” wore HPDs in these situations.
The primary source of noise exposure for
the students was loud music—at concerts,
nightclubs, or via personal stereo equipment. It is impossible to quantify the
amounts of these exposures for individuals
or study groups, but it is important to
remember that nonoccupational noise was
a factor in the hearing loss exhibited by
some participants.
Sound intensities generated by
high-speed handpieces
The Bruel & Kjaer sound level meter
was used to measure the peak sound
intensities (A-weighted) generated by
instruments while they were being used
during dental procedures. The sound
meter’s microphone was positioned near
General Dentistry
May/June 2015
73
Practice Management & Human Relations Hearing loss associated with long-term exposure to high-speed dental handpieces
the clinician’s ear that was closest to the
handpiece during the procedure. The
following peak sound intensities were
recorded: Midwest Tradition High-Speed
Handpiece (DENTSPLY International)
with friction grip No. 2 round bur,
88-94 dB SPL; Micro-Mega High-Speed
Handpiece with No. 4 round carbide
bur, 98-102 dB SPL; and Cavitron
Select Ultrasonic Scaler (DENTSPLY
International), 92-98 dB SPL.
These sound intensities are high enough
to contribute to cochlear damage and
noise-induced hearing loss over time.2,3
Although the DCs’ duration of exposure
to these sounds might be relatively brief
(as little as 30-45 minutes per day), the
cumulative effects of such exposures over
years or decades of practice might very
well contribute to occupational hearing
loss and/or tinnitus for some individuals.
Additional sources of loud sounds in a
clinic (such as suction devices or other
instruments being used in nearby operatories) can also increase clinicians’ total noise
exposure and risk for developing NIHL.
Discussion
Because this was a pilot study with a
relatively small number of participants,
the results are considered preliminary.
Potential confounding factors—including
age and gender of participants, duration
and type of handpiece usage throughout
each person’s career, and precise
measurements of occupational and
recreational noise exposure—were not
controlled in this investigation. In spite
of these limitations, the sloping highfrequency hearing loss exhibited by DCs
in this study is consistent with long-term
exposure to loud sounds. Measurements of
sound levels generated by instruments in
the current study revealed intensities that
can contribute to the pattern of hearing
loss observed in the DC group. However,
age, genetics, and other sources of loud
sounds also contributed to the hearing loss
exhibited by subjects in this study. While
hearing loss due to aging or genetic factors
is not preventable, NIHL can be prevented
by using HPDs in noisy environments.
The lack of HPD use by DCs and
DSs in this study is not surprising
considering their use (or lack thereof)
in the workplace overall. Workers in
noisy conditions—including industrial
74
May/June 2015
General Dentistry
Table 3. Multiple comparisons of audiometric thresholds at tested frequencies.
95% confidence interval
Frequency
Group
Groups
Mean
difference
Lower
Upper
RE 500 Hz
DC
DP
3.08
0.659
-3.12
9.27
DS
5.00
0.266
-2.19
12.19
RE 1000 Hz
DC
DP
5.58
0.130
-1.12
12.27
DS
5.63
0.231
-2.14
13.39
RE 2000 Hz
DC
DP
7.16
0.332
-3.85
18.18
DS
10.63
0.131
-2.15
23.40
RE 3000 Hz
DC
DP
19.30
0.055
-0.31
38.92
DS
22.19
0.058
-0.56
44.94
RE 4000 Hz
DC
DP
21.73*
0.036
1.12
42.34
DS
23.75
0.052
-0.15
47.65
RE 6000 Hz
DC
DP
22.33*
0.012
4.19
40.47
DS
30.94*
0.002
9.90
51.97
RE 8000 Hz
DC
DP
23.49*
0.008
5.22
41.75
DS
29.83*
0.003
8.73
50.93
LE 500 Hz
DC
DP
5.07
0.238
-1.99
12.14
DS
5.31
0.335
-2.88
13.50
LE 1000 Hz
DC
DP
6.64
0.091
-0.75
14.02
DS
6.25
0.225
-2.32
14.82
LE 2000 Hz
DC
DP
6.23
0.612
-5.88
18.34
DS
11.56
0.137
-2.48
25.61
LE 3000 Hz
DC
DP
15.12
0.134
-3.14
33.38
DS
21.56*
0.045
0.39
42.73
LE 4000 Hz
DC
DP
16.64
0.156
-4.16
37.43
DS
25.00*
0.040
0.88
49.12
LE 6000 Hz
DC
DP
17.48
0.106
-2.61
37.56
DS
24.69*
0.035
1.39
47.98
LE 8000 Hz
DC
DP
22.09*
0.045
0.41
43.77
DS
25.94*
0.041
0.80
51.08
P value
*Designates clinical significance ( P < 0.05). Abbreviations: DCs, dental clinicians; DPs, dental professionals;
DSs, dental students; LE, left ear; RE, right ear.
and military environments—often
have low rates of HPD utilization, even
after they have been ordered to use the
devices.31-34 Reasons for not using HPDs
during noisy dental procedures include
discomfort, fear that HPDs will interfere
with communication, inconvenience,
negative feedback from coworkers or
patients, and the belief that noise levels
from dental instruments will not damage
hearing. In fact, earplugs equipped with
www.agd.org
filters (known as musician’s earplugs)
will not interfere with a clinician’s ability
to understand coworkers or patients.
Custom-made musician’s earplugs can
be obtained from any practitioner who
fits patients with hearing aids, such as
an audiologist or hearing aid dispenser.
Noncustom (and therefore disposable)
musician’s earplugs are also available.
While these disposable earplugs may only
provide minimal noise reduction (15 dB
of attenuation), it is enough to greatly
reduce a clinician’s risk of developing
NIHL from the noise generated by
handheld instruments.6 Patients can
also be given the opportunity to wear
disposable foam ear plugs during dental
procedures. However, patients who are
exposed to noise from dental instruments
only occasionally have minimal risk
of developing NIHL or tinnitus from
this sound source.
Results from this study are consistent
with the findings of previous studies that
showed clinicians who operate dental
handpieces or other loud instruments
are at risk of developing NIHL. Multiple
factors contribute to this risk, including
variations in the frequency composition
of the noise, the number of hours per
week that handheld devices are used, and
variations in sound intensity over time
related to turbine speed and maintenance
of the devices. Setcos & Mahyuddin
described these and additional factors
in a 1998 article.26 It is unlikely that
a DC’s daily exposure to high-speed
handpieces will surpass OSHA’s PEL for
an 8-hour workday. However, it is the
authors’ opinion that OSHA standards
are probably not stringent enough and
also do not take individual susceptibilities
to NIHL or tinnitus into account.
Conclusion
To decrease their risk of developing NIHL,
dental practitioners are encouraged to
follow the recommendations by the ADA
Council on Dental Materials and Devices,
which states:
…preventive measures for noise attenuation should be directed in three areas: optimum maintenance of rotary equipment,
reduction of the ambient noise level in the
operatory (soundproofing, acoustical ceilings, baffle drapes, resilient floors, rational location of the compressor and other
noise-making equipment), and personal
protection through the use of ear plugs.22
Additionally, the ADA Council recommended that
…practitioners concerned about the potential impairment should have an otologic
examination and have an audiometric
evaluation in a silent room to assess the
present condition. Noise levels in the
individual offices should be studied with
monitoring periods of more than a week.
An audiometric evaluation should be
made after a typical workday and again
at the beginning of the next day to observe
temporary threshold shift and apparent
recovery. Annual tests of hearing should
be taken.22
To these recommendations, the authors of
the present study suggest adding the caveat
that hearing protection strategies should
always be implemented during noisy recreational as well as occupational activities.
Regarding future research in this
area, the authors concur with Hyson in
recommending that additional studies
should be conducted to investigate the
hearing loss potential among students,
faculty members, practicing dentists, and
other dental staff members who work
with air-turbine handpieces; to determine
whether there is a correlation between
the use of the air turbine and hearing
loss; and to determine whether dentists
and staff members should wear ear
protection.35 The following investigations
could yield valuable information:
• Longitudinal studies of students,
faculty members, practicing dentists,
and hygienists to assess their hearing
annually and to determine if they
exhibit NIHL or tinnitus. Regarding
tinnitus, Devlin & Leandro wrote
about a clinician’s personal experience:
I have been practicing dentistry for
15 years now. About 7 years ago, I
developed tinnitus in my left ear. It
is an annoying, high-pitched whine,
sounding almost like a high-speed
handpiece that runs 24 hours a
day, 7 days a week. Although it was
uncertain as to why I developed this
condition, I wish that I had started
wearing earplugs in dental school,
and had continued the practice
throughout my dental career.28
• A large-scale study of the current
hearing protection practices of DCs.
This study should include questions
regarding their attitudes and behaviors
related to utilization of HPDs.
• A study to determine if specific
educational interventions related
www.agd.org
to hearing and noise exposure
would affect the attitudes and
behaviors of DCs regarding hearing
loss prevention practices.
• A study to determine which
HPDs are preferred by DCs.
Author information
Drs. Theodoroff and Folmer are research
investigators for the US Department
of Veterans Affairs (VA) Rehabilitation
Research and Development Service
(RR&D), National Center for
Rehabilitative Auditory Research, Portland
VA Medical Center, Oregon, and assistant
and associate professors, respectively,
Department of Otolaryngology, Head
and Neck Surgery, Oregon Health
& Science University, Portland.
Acknowledgments
Support for this study was provided by
the Tinnitus Clinic and Department of
Otolaryngology at OHSU. Additional
support was provided by the VA
National Center for Rehabilitative
Auditory Research (funded by the VA
RR&D Center of Excellence grant
No. C9230C) at the Portland VA
Medical Center, Oregon. The authors
wish to thank April Kaelin, faculty
members, staff, and students at the
OHSU School of Dentistry for their
assistance with data collection.
References
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2000;37(1):112-120.
2. National Institute on Deafness and Other Communication Disorders (NIDCD). Noise-Induced Hearing Loss.
Available at: www.nidcd.nih.gov/health/hearing/pages/noise.aspx. Accessed March 3, 2015.
3. Occupational Safety and Health Administration. Occupational Noise Exposure; Hearing Conservation
Amendment; Final Rule. 29CFR1910.95. Federal Register. 1983;48(46):9738-9785.
4. Barek S, Adam O, Motsch JF. Large band spectral analysis and harmful risks of dental turbines. Clin Oral Investig. 1999;3(1):49-54.
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6. Sorainen E, Rytkonen E. Noise level and ultrasound
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8. Kadanakuppe S, Bhat PK, Jyothi C, Ramegowda C. Assessment of noise levels of the equipments used in the
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9. Centers for Disease Control and Prevention. National
Institute for Occupational Safety and Health. Noise and
Hearing Loss Prevention. Available at: http://www.cdc.
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13. Zubick HH, Tolentino AT, Boffa J. Hearing loss and
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14. Wilson JD, Darby ML, Tolle SL, Sever JC Jr. Effects of
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16. Gijbels F, Jacobs R, Princen K, Nackaerts O, Debruyne
F. Potential occupational health problems for dentists
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17.Bali N, Acharya S, Anup N. An assessment of the effect of sound produced in a dental clinic on the hearing of dentists. Oral Health Prev Dent. 2007;5(3):
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18. Messano GA, Petti S. General dental practitioners and
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19. Forman-Franco B, Abramson AL, Stein T. High-speed
drill noise and hearing: audiometric survey of 70 dentists. J Am Dent Assoc. 1978;97(3):479-482.
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20. Rahko AA, Karma PH, Rahko KT, Kataja MJ. High-frequency hearing of dental personnel. Community Dent
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29. Serafini F, Biasi CSL, Serafini ST, do Rio F, Zinani A.
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their use of personal hearing protection devices. Med J
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Manufacturers
Beltone, Glenview, IL
800.235.8663, www.beltone.com
Bruel & Kjaer Sound & Vibration Measurement A/S,
Naerum, Denmark
45.7741.2000, www.bksv.com
DENTSPLY International, York, PA
800.877.0020, www.dentsply.com
KaVo Dental, Charlotte, NC
800.452.1472, www.kavousa.com
MICRO-MEGA SA, Besancon, France
33.381.54.4242, micro-mega.com
Siemens Corporation, Washington, DC
800.743.6367, www.usa.siemens.com
Exercise No. 369 Practice
Management & Human Relations Subject Code 550
The 15 questions for this exercise are based on the article, Hearing
loss associated with long-term exposure to high-speed dental
handpieces, on pages 71-76. This exercise was developed by Robert
A. Busto, DMD, MBA, FAGD, in association with the General Dentistry
Self-Instruction committee.
1. The National Institute on Deafness and
Other Communication Disorders claims
that approximately ____% of Americans
between the ages of 20 and 69 have high
frequency hearing loss that may have
been caused by exposure to loud sounds
or noise at work or in leisure activities.
A. 5
B. 10
C. 15
D. 20
2. According to OSHA, the maximum
permissible exposure limit (PEL) in an
8-hour day should not exceed _____
decibels sound pressure level using an
A-weighted scale (dBA SPL).
A. 90
B. 95
C. 100
D. 105
3. OSHA recommends a maximum
of _____dBA SPL for a 4-hour PEL.
A. 90
B. 95
C. 100
D. 105
4. High frequencies become audible
below ________ Hz.
A. 21,000
B. 20,000
C. 19,000
D. 18,000
5. _____ exposure, _____ intensity will likely
contribute most to auditory dysfunction.
A. Long; high
B. Short; high
C. Long; low
D. Short; low
6. According to the OSHA standard, the
PEL for 105 dB is _____ hour(s).
A. 4
B. 3
C. 2
D. 1
Reading the article and successfully completing this exercise will
enable you to:
•learn about noise-induced hearing loss (NIHL);
•understand the risk of NIHL among dental professionals; and
•follow recommended methods to prevent NIHL.
7. Because dental professionals do not use
high-speed handpieces continuously
during the workday, they do not
usually exceed OSHA’s PEL. Additional
sources of loud sounds in a clinic, such
as suction devices being used in nearby
operatories, will not increase risk for
developing NIHL.
A. Both statements are true.
B. The first statement is true;
the second is false.
C. The first statement is false;
the second is true.
D. Both statements are false.
8. The noise-induced hearing loss
exhibited by dental clinicians was
characterized by elevated auditory
thresholds at __________Hz.
A. 4000-6000
B. 7000-9000
C. 10,000-12,000
D. 13,000-15,000
9. The ADA Council on Dental Materials
and Devices recommends that
preventive measures for noise
attenuation should include “personal
protection through the use of ear
plugs.” Additionally, the Council
recommended that “practitioners
concerned about the potential
impairment should have an audiometric
evaluation in a silent room to assess the
present condition.”
A. Both statements are true.
B. The first statement is true;
the second is false.
C. The first statement is false;
the second is true.
D. Both statements are false.
10. All of the following pure tone
audiometric frequencies were collected
except one. Which is the exception?
A. 500 Hz
B. 1500 Hz
C. 3000 Hz
D. 6000 Hz
11. _______ dental clinicians who regularly
used high-speed handpieces were
included in the study.
A. Twenty
B. Sixteen
C. Thirteen
D. Eight
12. All of the following are reasons given
for failing to use hearing protection
devices except one. Which is the
exception?
A. fear they will interfere with
communication
B. negative feedback from coworkers
or patients
C. belief that noise levels from dental
instruments will not damage hearing
D. high cost is prohibitive
13. All of the following factors associated
with dental handpieces increase the
risk of NIHL except one. Which is the
exception?
A. variations in frequency composition of
the noise
B. number of hours per week the device is
used
C. proper maintenance of the devices
D. sound intensity over time
14. Attenuating _______ db of noise
generated by handheld instruments is
enough to reduce a clinician’s risk of
developing NIHL.
A.5
B.10
C.15
D.20
15. Ambient noise levels can be reduced by
all of the following except one. Which
is the exception?
A. acoustical ceilings
B. baffle drapes
C. marble floors
D. soundproofing
Answer form is on the inside back cover. Answers for this exercise must be received by April 30, 2016.
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General Dentistry
May/June 2015
77
Oral Diagnosis
Douglas D. Damm, DDS
Apical lesion of mandibular bicuspid (Case courtesy of Dr. Michael A. Herman, Dayton, OH.)
A periapical radiograph was obtained from a 35-year-old
male patient and revealed a radiopacity fused to the root
of the mandibular first bicuspid on the right side (Fig. 1).
The lesion was asymptomatic and not associated with any
significant cortical expansion. The tooth responded within
normal limits upon vitality testing.
Which of the following is the most appropriate diagnosis?
A.Cementoblastoma
B. Cemento-osseous dysplasia
C. Condensing osteitis
D.Hypercementosis
Fig. 1. Radiopacity fused to the root of the
mandibular first bicuspid on the right side.
Diagnosis is on page 79.
Apical lesion of maxillary molar (Case courtesy of Dr. Michael Bobo, Murray, KY.)
A 16-year-old male patient presented with
discomfort and expansion of the posterior
maxilla on the left side. The teeth within the
quadrant responded within normal limits to
vitality testing. A periapical radiograph revealed
a radiopacity surrounding and continuous with
the distal root of the maxillary first molar (Fig.
1). An incisional biopsy was performed (Fig. 2).
Which of the following is the most
appropriate diagnosis?
A.Cementoblastoma
B. Cemento-osseous dysplasia
C. Condensing osteitis
D.Hypercementosis
Fig. 1. Radiopacity surrounding and continuous with
the distal root of the maxillary first molar.
Fig. 2. Numerous basophilic globules and sheets
of plasmacytoid osteoblast-like cells (H & E stain,
original magnification 20X).
Diagnosis is on page 79.
Author information
Dr. Damm is a professor, Department of Oral Health Sciences, Division of Oral Pathology, College of Dentistry, University of Kentucky, Lexington.
78
May/June 2015
General Dentistry
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Answers
Oral Diagnosis
Apical lesion of mandibular bicuspid
Diagnosis:
B. Cemento-osseous dysplasia
Cementoblastomas present as radiopaque tumor-like masses
fused to the root of a tooth and surrounded by thin radiolucent
periodontal ligament. The current case closely mimics this radiographic pattern. Despite the close radiographic similarities, the
clinical presentation is not typical for the diagnosis of cementoblastoma. Approximately 75% of cementoblastomas arise prior to
the age of 30, and close to 70% of affected patients complain of
pain with significant associated expansion.
Cemento-osseous dysplasia (osseous dysplasia) may be localized
to the anterior mandible (periapical variant), multifocal beyond
the anterior mandible (florid variant), or isolated (focal variant).
The lesions initially appear radiolucent but develop intermixed
opacities over time. Upon full maturation, cemento-osseous
dysplasia becomes predominantly opaque with a thin radiolucent
rim. During this stage, the altered bone is hypovascular with an
increased prevalence of osteonecrosis when secondarily inflamed.
In addition, ankylosis with adjacent teeth can occur and create a
pattern that mimics cementoblastoma. Patients should be encouraged to practice excellent oral hygiene to prevent significant
inflammation of the altered bone.
Apical lesion of maxillary molar
Diagnosis:
A. Cementoblastoma
Incisional biopsy revealed radiating trabeculae of cellular woven
bone-like material intermixed with numerous basophilic globules and sheets of plasmacytoid osteoblast-like cells (Fig. 2).
Microscopically, cementoblastoma is identical to the osseous
neoplasm, osteoblastoma, with attachment to a tooth utilized to
separate these closely related pathoses.
As mentioned in the previous case (cemento-osseous dysplasia),
the vast majority of cementoblastomas arise before the age of 30
years and usually present with pain and swelling. Approximately
90% originate in the posterior region with close to 50% associated with a permanent first molar. Involvement of the deciduous
dentition is rare. The tumor is truly neoplastic and mandates
assured surgical removal.
Reference
Neville BW, Damm DD, Allen CM, Bouquot JE. Oral and Maxillofacial Pathology. 3rd ed. St.
Louis: Saunders/Elsevier; 2009:655-656.
Reference
Neville BW, Damm DD, Allen CM, Bouquot JE. Oral and Maxillofacial Pathology. 3rd ed. St.
Louis: Saunders/Elsevier; 2009:640-645, 655-656.
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General Dentistry
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79
Self-Instruction
Exercise No. 349
May/June 2014, p. 45
1. A
5. A
9. D
13. A
2. A
6. A
10. D
14. C
3. B
7. D
11. B
15. B
Exercise No. 350
4. D
8. C
12. D
May/June 2014, p. 53
1. B
5. D
9. A
13. C
2. D
6. D
10. A
14. B
Erratum
3. C
7. A
11. B
15. B
Exercise No. 351
4. A
8. B
12. C
May/June 2014, p. 62
1. D
5. C
9. C
13. D
2. A
6. A
10. B
14. A
3. D
7. C
11. D
15. A
4. A
8. D
12. C
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With regard to the article, Maxillary first molar with 8 root canals
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the correct author information reads: Dr. Almeida is a professor,
Endodontics, Brazilian Dental Association, ABO, Ilheus, Bahia,
Brazil. Dr. Machado is a doctoral student, Endodontics, Ribeirao
Preto Dental School, University of Sao Paulo, Brazil; a professor, Endodontics, School of Dentistry, Paranaense University,
Francisco Beltrao, Parana, Brazil; and in private endodontic practice in Navegantes, Santa Catarina, Brazil. Dr. Cunha is a professor, Endodontics, School of Dentistry, University of Manitoba,
Winnipeg, Canada. Dr. Vansan is a professor, Department of
Endodontics, Ribeirao Preto Dental School, University of Sao
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Saveetha Dental College and Hospitals, Saveetha University,
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368
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Dental Materials
Evaluation of the bond strengths of 3 endodontic
cements via push-out test
Nadia de Souza Ferreira, PhD n Raffaela Di Iorio Jeronymo Ferreira, PhD n Patricia Campos Ferreira da Rosa, MS Ana Paula Martins Gomes, PhD n Carlos Henrique Ribeiro Camargo, PhD n Claudio Antonio Talge Carvalho, PhD Marcia Carneiro Valera, PhD
In this study, the push-out method was used to evaluate the bond
strengths of 3 types of endodontic cements according to their composite
base: methacrylate, epoxy resin, and an experimental copaiba oil resin.
The study hypothesis was that the methacrylate-based and experimental
cements would have bond strengths equal to or greater than that of the
epoxy resin-based cement. Thirty bovine tooth roots, 18 mm long, were
divided into 3 groups (n = 10) based on the chosen cement treatment.
After treatment, the specimens were sectioned and submitted to a
O
ne of the objectives of root canal
filling is to obtain adequate sealing
between the filling material and root
canal walls in order to prevent the reinfection of the root canal system and improve
the success of endodontic treatments.
Moreover, it is frequently necessary in
endodontic treatment to use intraradicular
retainers to reconstruct the teeth prosthetically. However, a rupture of the filling seal
may occur due to mechanical stress caused
by the flexure of the tooth or the preparation for the post. Therefore, the mechanical
forces at the dentin-cement interface are
important factors to consider when selecting a filling material.1
Endodontic cement bonding is defined
as the ability of a cement to adhere to the
root canal walls and promote the bond
of the gutta percha cones to each other
and to dentin.2 It has been suggested that
a cement’s capacity to adhere to gutta
percha and dentin may result in a greater
sealing ability, thus reducing coronal and
apical leakage.3,4
EndoREZ (Ultradent Products, Inc.) is
a methacrylate-based endodontic cement
that uses hydrophilic monomers to
improve its penetration into the dentinal
tubules after removal of the smear layer
from the canal and is designed for use
with a single gutta percha cone.5-7 AH
Plus (DENTSPLY Maillefer) is an epoxy
resin-based cement that has shown good
physicochemical properties, low solubility, good bonding, antimicrobial action,
and good biological properties and is
push-out test. Results showed that there was no statistically significant
difference (P < 0.05) between the cements used or between the middle
and apical thirds of the roots. It could be concluded that the tested cements had satisfactory and similar bond strengths to dentin.
Received: February 27, 2013
Accepted: May 21, 2013
Key words: root canal, endodontics, dentinal bonding
widely considered the endodontic cement
of choice for the majority of cases.8-11
Recently, natural extracts have been
extensively studied in endodontics. A
copaiba oil-based resin (derived from
Copaifera multijuga) has been shown
to have healing, analgesic, and antiinflammatory properties as well as good
biocompatibility and a rigid structure.12,13
This oil-based resin has been used in the
reconstruction, replacement, and filling
of bone defects.14 Thus, an experimental
copaiba oil resin-based sealer (Biosealer)
created by Garrido et al may be suitable for clinical use; however, little is
known about the bonding ability of this
endodontic cement.15
The purpose of this study was to
evaluate—by means of the push-out
method—the bonding capabilities of AH
Plus, EndoREZ, and Biosealer to the root
dentin of bovine teeth.
The study hypothesis was that the
EndoREZ cement and the Biosealer would
have bond strengths equal to or greater
than those of AH Plus cement.
Materials and methods
Thirty bovine teeth were cleaned with
periodontal curettes and stored in
physiological solution until they were
used in this study. The crowns of the
teeth were removed with a diamond
disc (90 µm, Microdont) at low speed
under constant cooling, and the root
remainder was standardized to a length
of 18 mm.
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All the canals were manually prepared
up to 17 mm with K files (DENTSPLY
Maillefer) up to a K-50 file and scaled
with progressively programmed withdrawal (every 1 mm) with up to a K-80
file. During biomechanical preparation,
the canals were irrigated with 5 ml of
2.5% sodium hypochlorite with every
change of a K file. After this, the canals
were irrigated with 1 ml of 17% EDTA for
3 min, and final irrigation was performed
with 5 ml of saline solution.
The roots were divided into groups
(n = 10) according to the filling cement
used: Group 1, AH Plus; Group 2,
EndoREZ; Group 3, Biosealer. The
most apical portions of the specimens
were embedded in 3 mm of colorless
acrylic resin (Jet, Artigos Odontologicos
Classico, Ltda). During this procedure,
the specimens were maintained perpendicular to the ground, according to the
following protocol: 1 Largo bur No. 3
(DENTSPLY Maillefer) was inserted into
the prepared canal; the set was fixed in an
adapted delineator so that the long axes of
the cutter, specimen, and vertical mobile
rod of the delineator remained parallel to
one another and to the y-axis; the acrylic
resin was manipulated and poured into a
silicone mold; then the bur/specimen set
was lowered to the 3 mm mark and fixed
in the acrylic resin.
After this procedure, the specimens of
Groups 1 and 3 were completely dried
with absorbent paper cones and filled
with their respective endodontic cements
General Dentistry
May/June 2015
e1
Dental Materials Evaluation of the bond strengths of 3 endodontic cements via push-out test
with the aid of a Lentulo spiral connected
to a counter-angle at low speed. The
AH Plus cement was proportioned and
spatulated in accordance with the manufacturer’s instructions. The Biosealer was
spatulated using 0.43 g of powder and 0.2
ml of liquid.15
The specimens of Group 2 were
left humid for filling with the aid of a
Lentulo spiral connected to a counterangle at low speed; after filling, they
were light polymerized for 40 seconds
(in accordance with the manufacturer’s
recommendations) with the tip of a
light-polymerizing unit (Curing Light
XL3000, 3M ESPE) placed in the cervical opening of the canal.
All the specimens were stored in an oven
at 37°C and 100% humidity for 7 days to
allow the endodontic cements to set completely. After the cements had hardened,
the specimens were fixed onto a metal base
in a cutting machine (LabCut 1010, Extec
Corp.) and sectioned perpendicular to the
long axis of the root, using a diamond disc
(WFR BLDE 4 x 0.12 × 0.5 inch, Extec
Corp.) under constant water cooling. The
first cervical slice (approximately 1 mm
thick) was discarded.
For each specimen, 4 slices, each
approximately 2 mm thick, were obtained.
For the push-out test, the first slice, representative of the middle third of the root,
and the fourth slice, representative of the
apical third, were used.
During the mechanical test, each specimen was placed with the most coronal
face of the specimen facing down, and a
load was applied (in the direction of the
apical to the coronal) until the cement was
debonded. The test was performed in a
universal testing machine (EMIC Model
DI-1000, EMIC Equipamentos e Sistemas
de Ensaio LTDA) at a speed of 1 mm/min
with a load cell of 50 kgf.
The original data obtained in the pushout test were submitted to descriptive
and inferential statistical analysis using a
2-way ANOVA test with a level of significance of 5%.
Results
The data (in MPa) that demonstrated
normal distributions of the samples—
thereby enabling the performance of
parametric tests—were submitted to preliminary tests.
e2
May/June 2015
General Dentistry
The data used for this study were the
values corresponding to the maximum
stresses borne by each filling cement before
it was debonded from the root canal walls.
In each of the 3 groups, 10 specimens
were used with 2 values each for their
middle and apical thirds so that a total of
60 values were obtained.
The Table shows the mean values and
standard deviations of the maximum force
of resistance to displacement for each
cement used.
The values were submitted to a 2-way
ANOVA test. The ANOVA demonstrated
that there was no statistically significant
difference (P < 0.05) between the endodontic cements used or between the
middle and apical thirds.
Discussion
Periapical tissue repair after endodontic
treatment partly depends on the chemical
composition and physicochemical properties of the filling materials.16
Copaiba oil-resin is a polyester formed by
an amine radical that gives it a bactericidal
effect, causing damage to the bacterial cell
walls and thus increasing their biocompatibility with living tissues.17,18 The possibility
of a chemical reaction between the acid
components of the copaiba oil-resin and the
alkaline constituents of calcium hydroxide
and zinc oxide have resulted in the development of phytotherapeutic cements. Zinc
oxide may act as a base, reacting with the
acids of the copaiba oil-resin and causing
the cement to assume a rigid structure.15
Resin epoxy-based cements penetrate
deeply into microirregularities due to their
fluidity throughout their polymerization
process, thus contributing to the mechanical
interlocking between the cements and the
dentin.19 In addition to this interlocking, the
adhesiveness of the AH Plus cement is due
to the formation of covalent bonds between
the epoxide rings and the exposed amino
acids in the dentin collagen network.20
These factors are associated with the cohesion between the molecules of the cement
that increase the resistance to removal or
to displacement of the material from the
dentinal surface, a property that translates
into excellent bonding.21,22 Moreover, resin
epoxy-based cements penetrate into the
dentinal tubules exposed after removal of
the smear layer, forming tags similar to those
that occur with the adhesive systems.23
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Table. Mean (standard deviation)
values (N) of the maximum force of
resistance to displacement obtained
for the 2 different thirds of the
bovine teeth and the 3 endodontic
cements used in the study.
Groups
(n = 10)
Third
Apical
Middle
1
2.430 (1.860)
2.655 (1.304)
2
2.356 (1.806)
2.476 (1.458)
3
2.601(2.275)
2.726 (1.748)
In 2012 Chadha et al found greater
penetration of the EndoREZ cement into
dentinal tubules in comparison with AH
Plus cement; however, Fisher et al in 2007
and Eldeniz et al in 2005 found lower
bond strength values for EndoREZ when
compared with AH Plus.9,20,24
The hydrophilic property of EndoREZ
cement necessitates its use in humid root
canals, thereby increasing its penetration
into the dentinal tubules; however, its
bond may be prejudiced by polymerization
shrinkage due to the thick layer of cement
that is frequently associated with the filling
of a single gutta percha cone.5,25,26
To minimize the effect of this polymerization shrinkage, a filling technique may
be used in which, after injection of the
EndoREZ cement into the canal, a main
cone is placed and accessory cones are
passively inserted, thereby reducing the
volume of the cement.5,27
Moreover, with methacrylate-based
cements, the lack of light activation
throughout the entire extension of the
root canal—due to the reduction in exposure to light in the deeper regions of the
canal—contributes to incomplete polymerization, leaving residual monomers that
may contribute to a reduction in bonding
to the dentin; the oxygen present on
the root canal walls and in the dentinal
tubules may also affect the polymerization process.22,28 In the present study,
the numerical values of bond strength
to dentin were lower for the EndoREZ
cement; however, there was no statistically
significant difference between the studied
cements. In this study, the canals were
filled only with cement, differing from
clinical practice in which cones are used,
especially the gutta percha type. However,
the use of gutta percha cones makes the
push-out test unfeasible since, once the
bond between the cement and the cones is
ruptured, it becomes difficult to evaluate
the bond of the cement to the dentin.
Moreover, it was verified that the bond
strengths of the cements were similar,
irrespective of their locations (apical or
middle third), since the variations in
tubular density and sclerotic dentin along
the root canal do not alter their mechanical retentions.1 Thus, the results of this
study showed that the bond strengths
of the studied cements were similar,
demonstrating that in these conditions,
EndoREZ has adequate bond strength
and that Biosealer has promising potential for use in endodontic practice.
Conclusion
It could be concluded that the bond
strengths of EndoREZ and Biosealer were
similar to that of AH Plus and that the
root third did not interfere in the bond
strengths of the studied cements.
Author information
Ms. N. Ferreira is an auxiliary professor, Federal University of Pelotas, Brazil.
Dr. R. Ferreira is a dentist, Department
of Restorative Dentistry, Universidade
Estadual Paulista, Sao Paulo, Brazil, where
Drs. Gomes, Camargo, and Carvalho are
adjunct professors, and Dr. Valera is a full
professor. Ms. da Rosa is dentist.
Disclaimer
The authors have no financial, economic,
commercial, and/or professional interests
related to topics presented in this article.
References
1. Babb BR, Loushine RJ, Bryan TE, et al. Bonding of selfadhesive (self-etching) root canal sealers to radicular
dentin. J Endod. 2009;35(4):578-582.
2. Sousa-Neto MD, Silva Coelho FI, Marchesan MA, Alfredo E, Silva-Sousa YT. Ex vivo study of the adhesion
of an epoxy-based sealer to human dentine submitted
to irradiation with Er:YAG and Nd:YAG lasers. Int Endod J. 2005;38(12):866-870.
3. Saleh IM, Ruyter IE, Haapasalo MP, Orstavik D. Adhesion of endodontic sealers: scanning electron microscopy and energy dispersive spectroscopy. J Endod.
2003;29(9):595-601.
4. Neelakantan P, Subbarao C, Subbarao CV, De-Deus G,
Zehnder M. The impact of root dentine conditioning
on sealing ability and push-out bond strength of an
epoxy resin root canal sealer. Int Endod J. 2011;44(6):
491-498.
5. Tay FR, Loushine RJ, Monticelli F, et al. Effectiveness of
resin-coated gutta-percha cones and a dual-cured,
hydrophilic methacrylate resin-based sealer in obturating root canals. J Endod. 2005;31(9):659-664.
6. Bergmans L, Moisiadis P, De Munck J, Van Meerbeek
B, Lambrechts P. Effect of polymerization shrinkage on
the sealing capacity of resin fillers for endodontic use.
J Adhes Dent. 2005;7(4):321-329.
7. Kardon BP, Kuttler S, Hardigan P, Dorn SO. An in vitro
evaluation of the sealing ability of a new root-canalobturation system. J Endod. 2003;29(10):658-661.
8. Schafer E, Zandbiglari T. Solubility of root-canal sealers
in water and artificial saliva. Int Endod J. 2003;36(10):
660-669.
9. Eldeniz AU, Erdemir A, Belli S. Shear bond strength of
three resin based sealers to dentin with and without
the smear layer. J Endod. 2005;31(4):293-296.
10. Kayaoglu G, Erten H, Alacam T, Orstavik D. Short-term
antibacterial activity of root canal sealers towards Enterococcus faecalis. Int Endod J. 2005;38(7):483-488.
11.Willershausen B, Marroquin BB, Schafer D, Schulze R.
Cytotoxicity of root canal filling materials to three
different human cell lines. J Endod. 2000;26(12):
703-707.
12. Camargo SE, Rode Sde M, do Prado RF, Carvalho YR,
Camargo CH. Subcutaneous tissue reaction to castor
oil bean and calcium hydroxide in rats. J Appl Oral Sci.
2010;18(3):273-278.
13. Carvalho JC, Cascon V, Possebon LS, et al. Topical antiinflammatory and analgesic activities of Copaifera
duckei dwyer. Phytother Res. 2005;19:946-950.
14. Leite FR, Ramalho LT. Bone regeneration after demineralized bone matrix and castor oil (Ricinus communis )
polyurethane implantation. J Appl Oral Sci. 2008;
16(2):122-126.
15. Garrido AD, Lia RC, Franca SC, da Silva JF, Astolfi-Filho
S, Sousa-Neto MD. Laboratory evaluation of the physicochemical properties of a new root canal sealer
based on Copaifera multijuga oil-resin. Int Endod J.
2010;43(4):283-291.
16. Brackett MG, Marshall A, Lockwood PE, et al. Inflammatory suppression by endodontic sealers after aging
12 weeks in vitro. J Biomed Mater Res B Appl Biomater. 2009;91(2):839-844.
17. Calixto RF, Teofilo JM, Brentegani LG, Carvalho TL. Implantation of flakes of castor oil resin in rat dental alveolus [in Portuguese]. Pesqui Odontol Bras. 2001;
15(3):257-262.
18. Santos AO, Ueda-Nakamura T, Dias Filho BP, Veiga Junior VF, Pinto AC, Nakamura CV. Antimicrobial activity
of Brazilian copaiba oils obtained from different species of the Copaifera genus. Mem Inst Oswaldo Cruz.
2008;103(3):277-281.
www.agd.org
19. Carneiro SM, Sousa-Neto MD, Rached FA Jr, Miranda
CE, Silva SR, Silva-Sousa YT. Push-out strength of root
fillings with or without thermomechanical compaction.
Int Endod J. 2012;45(9):821-828.
20. Fisher MA, Berzins DW, Bahcall JK. An in vitro comparison of bond strength of various obturation materials
to root canal dentin using a push-out test design.
J Endod. 2007;33(7):856-858.
21. Sousa-Neto MD, Marchesan MA, Pecora JD, Junior AB,
Silva-Sousa YT, Saquy PC. Effect of Er:YAG laser on adhesion of root canal sealers. J Endod. 2002;28(3):185187.
22. Nunes VH, Silva RG, Alfredo E, Sousa-Neto MD, SilvaSousa YT. Adhesion of Epiphany and AH Plus sealers to
human root dentin treated with different solutions.
Braz Dent J. 2008;19(1):46-50.
23. Haragushiku GA, Sousa-Neto MD, Silva-Sousa YT, Alfredo E, Silva SC, Silva RG. Adhesion of endodontic
sealers to human root dentine submitted to different
surface treatments. Photomed Laser Surg. 2010;28(3):
405-410.
24. Chadha R, Taneja S, Kumar M, Gupta S. An in vitro
comparative evaluation of depth of tubular penetration of three resin-based root canal sealers. J Conserv
Dent. 2012;15(1):18-21.
25. Kim YK, Grandini S, Ames JM, et al. Critical review on
methacrylate resin-based root canal sealers. J Endod.
2010;36(3):383-399.
26. Doyle MD, Loushine RJ, Agee KA, et al. Improving the
performance of EndoRez root canal sealer with a dualcured two-step self-etch adhesive. I. Adhesive strength
to dentin. J Endod. 2006;32(8):766-770.
27. Hiraishi N, Loushine RJ, Vano M, et al. Is an oxygen
inhibited layer required for bonding of resin-coated
gutta-percha to a methacrylate-based root canal sealer? J Endod. 2006;32(5):429-433.
28. Alfredo E, Silva SR, Ozorio JE, Sousa-Neto MD,
Brugnera-Junior A, Silva-Sousa YT. Bond strength of
AH Plus and Epiphany sealers on root dentine irradiated with 980 nm diode laser. Int Endod J. 2008;41(9):
733-740.
Manufacturers
Artigos Odontologicos Classico, Ltda, Sao Paulo, Brazil
55.11.3022.2588, www.classico.com.br
DENTSPLY Maillefer, Tulsa, OK
800.924.7393, www.maillefer.com
EMIC Equipamentos e Sistemas de Ensaio LTDA,
Sao Jose dos Pinhais, Brazil
55.42.3035.9400, www.emic.com.br
Extec Corp., Enfield, CT
800.543.9832, www.extec.com
Microdont, Sao Paulo, Brazil
55.11.3039.5500, www.microdont.com.br
Ultradent Products, Inc., South Jordan, UT
888.230.1420, www.ultradent.com
3M ESPE, St. Paul, MN
888.364.3577, solutions.3m.com
General Dentistry
May/June 2015
e3
Exodontia
Management of uncommon complications
in seemingly routine oral surgeries
Shayan Salim, BS n Andrew Newman, BS n James J. Closmann, DDS n Thomas J. Borris, DDS
Major complications in outpatient oral surgeries are relatively rare. This
article presents 4 cases of molar extraction with unusual complications
and describes how the clinician in each case altered the treatment,
resulting in a successful conclusion. The first case describes a fracture
during the removal of a maxillary first molar. The second case describes
a fracture after a mandibular third molar extraction. The third case
M
ost outpatient oral surgical procedures are performed with few, if
any, complications. When a major
complication occurs, management of the
situation is critical. The practitioner is
required to address the problem promptly
and seek help if indicated. This article
presents unusual complications found
in 4 cases and how these situations were
managed, in the hope that it will guide a
general dentist should he/she encounter
these scenarios while performing routine
outpatient procedures.
Case No. 1. Maxillary fracture
during first molar removal
A 23-year-old female patient presented
to her general dentist for extraction of
nonrestorable tooth No. 14. Her past
medical and surgical histories were noncontributory, and she had no allergies to
medications. After obtaining consent,
local anesthesia was administered. While
elevating the tooth, a cracking noise was
heard, and the tooth rotated downward.
Examination revealed the tooth was
attached to a segment containing the
alveolar bone, maxillary lateral wall, and
palatal bone (including the second and
third molars in that quadrant). A gross
malocclusion was noted. At that point, the
surgery was discontinued and a panoramic
radiograph was taken that revealed a fractured maxilla (Fig. 1).
The patient was referred to an oral
and maxillofacial surgeon for evaluation.
After a review of the fracture and medical
history, the patient was sedated and the
segment of maxilla was repositioned and
secured with a segmental stainless steel
arch bar and 24-gauge wire (Fig. 2).
The occlusion was adjusted slightly
and the patient was placed on amoxicillin 500 mg every 8 hours for 7 days,
Fig. 1. Case No. 1. Left maxillary fracture of the alveolar ridge, containing teeth
No. 14-16.
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May/June 2015
General Dentistry
describes a maxillary third molar displaced into the infratemporal space.
The final case describes necrosis of the maxillary soft tissue after fracture
of the tuberosity during a third molar extraction.
Received: January 16, 2014
Revised: June 4, 2014
Accepted: July 23, 2014
www.agd.org
pseudoephedrine 30 mg every 6 hours
for 7 days, and oxymetazoline nasal spray
(2 puffs per nostril) every 8 hours for 3
days. The patient was further instructed
to avoid nose-blowing for 3 weeks and
scheduled for follow-up in 1 week. The
patient recovered uneventfully, and the
arch bar was removed after 6 weeks.
The patient then returned to the clinic 6
weeks later to have tooth No. 14 removed
without incident.
Case No. 2. Mandibular fracture
after third molar surgery
A 24-year-old male patient presented to
his dentist for removal of his impacted
third molars (Fig. 3). The patient was
healthy and had a noncontributory
medical history, with no drug allergies
or contraindications to surgery. Written
consent was obtained. The third molars
were removed without incident under
Fig. 2. Case No. 1. Left maxillary fracture repositioned and stabilized with a
stainless steel segmental arch bar.
Fig. 3. Case No. 2. Preoperative panoramic radiograph for extraction of impacted
teeth No. 1, 16, and 17.
Fig. 4. Case No. 2. Postoperative panoramic radiograph revealing a nondisplaced
mandibular fracture in the left angle and closed reduction performed using
stainless steel arch bars and wire for maxillomandibular fixation.
Fig. 5. Case No. 2. One-week postoperative healing of nondisplaced mandibular fracture in the left angle,
without complications. Stainless steel arch bars and wire were removed 6 weeks postoperatively.
local anesthesia and intravenous sedation.
On postoperative day 3, the patient called
the office and stated he heard a “pop” in
his jaw while eating. He was instructed
to return to the office immediately, and
a panoramic radiograph was obtained,
revealing a nondisplaced mandibular
fracture in the left angle region (Fig. 4).
After the patient was presented with
treatment options, he elected to have
a closed reduction performed using
stainless steel arch bars with maxillomandibular fixation for 6 weeks. The
surgery was performed without incident,
and the patient was placed on penicillin V 500 mg every 6 hours for 1 week
and analgesics as needed. The patient
healed without complication (Fig. 5). The
arch bars were removed after 6 weeks
without malocclusion.
Case No. 3. Maxillary third
molar displaced into the
infratemporal space
A 21-year-old male presented to his
dentist for removal of his 3 remaining
impacted third molars (Fig. 6). The medical history was reviewed and noted to
be noncontributory. The patient had no
contraindications to surgery, and written
consent was obtained. Local anesthetic
was administered, and tooth No. 16
was exposed in the usual fashion with a
flap elevated in the subperiosteal plane.
A No. 301 elevator was placed on the
mesial aspect of the tooth and rotated
posteriorly. The tooth moved posteriorly
and superiorly and was visually lost with
a moderate amount of bleeding into
the site. At that point, the surgery was
stopped, the wound was closed, and the
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patient was placed on amoxicillin 500 mg
every 8 hours for 1 week; also prescribed
was acetaminophen with codeine 300/30
mg every 4-6 hours as needed to relieve
pain. The patient was referred for a
computed tomography (CT) scan of the
area to analyze the tooth 3-dimensionally
(Fig. 7 and 8).
The tooth was located in the infratemporal soft tissues and not in the maxillary sinus as suspected. The patient was
allowed to heal for 3 weeks then taken
back to surgery under general anesthesia to
remove the tooth through the same incision without incident.
Case No. 4. Necrosis of maxillary
soft tissue after tuberosity fracture
during third molar extraction
A 35-year-old male patient presented to
his dentist for extraction of tooth No.
16. The tooth was noted to have been in
full occlusal function with some minor
occlusal decay. The patient had a noncontributory past medical history and
smoked 1 pack of cigarettes per day. The
patient was scheduled for extraction of the
tooth under local anesthetic. A consent
form was signed, listing the usual complications of maxillary third molar surgery
including the risk of sinus injury. The
patient was anesthetized, and an attempt
to elevate the tooth with a No. 34 elevator
resulted in a cracking noise. Immediately
the tooth became mobile, and the soft
tissue was noted to move with the tooth
when further elevation was attempted. A
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May/June 2015
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Exodontia Management of uncommon complications in seemingly routine oral surgeries
Fig. 6. Case No. 3. Preoperative radiograph of impacted third molars.
tuberosity fracture was suspected, and the
decision was made to remove the tooth
and the segment of tuberosity (Fig. 9).
The resulting surgical site was noted
to contain a >6 mm sinus exposure.
The wound was closed in a watertight
fashion using the redundant soft tissue
and slowly resorbing sutures. The patient
was placed on amoxicillin 500 mg every
8 hours for 10 days, oxymetazoline nasal
spray (2 puffs per nostril) every 8 hours
for 3 days, pseudoephedrine 30 mg every
6 hours for 1 week, and, for pain relief,
acetaminophen with codeine 300/30 mg
every 4-6 hours. Additionally, the patient
was instructed not to blow his nose for
3 weeks and to avoid water sports and
flying in unpressurized aircraft. The
patient returned to the clinic approximately 1 week postsurgery and presented
with halitosis and a surgical site that
appeared to have a necrotic flap covering
the wound (Fig. 10).
The patient was instructed to continue
his antibiotic therapy, avoid smoking, and
to rinse with lukewarm saline 3-4 times
daily and was scheduled for a 1 week
follow-up. At that visit, the patient stated
that he had expectorated a large piece
of dead tissue. Upon examination, the
wound was slightly open but appeared to
be healing without infection. A small (<2
mm) sinus perforation was noted. Three
weeks later, the wound had closed. The
patient recovered uneventfully without
any complaints of sinus symptoms.
Fig. 9. Case No. 4. Segment of tuberosity and tooth
No. 16 removed after fracture of the tuberosity.
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May/June 2015
General Dentistry
Fig. 7. Case No. 3. Computed
tomography (CT) coronal view of tooth
No. 16 (arrow) displaced into the
infratemporal space.
www.agd.org
Fig. 8. Case No. 3. CT transverse view
of tooth No. 16 (arrow) displaced into
the infratemporal space.
Discussion
Case No. 1
The rate of maxillary tuberosity fractures
during molar extractions is relatively low
(0.15%).1 In adults, these fractures are
often associated with an enlarged maxillary
sinus, which can lead to oroantral fistula
formation or serious infection. These complications may result in maxillary necrosis
or, rarely, deafness. Studies utilizing CT
have shown that the posterior limit of the
maxillary sinus is located in the tuberosity
94% of the time; otherwise it is located in
the maxillary second molar area.2 In those
rare (6%) cases, the location may greatly
weaken the maxillary tuberosity and surrounding bone.2 Due to the necessity of
the maxillary tuberosity for stability of
Fig. 10. Case No. 4. Necrotic flap covering the wound of the surgical site 1 week
postsurgery.
Table 1. Authors’ procedural recommendations for maxillary fracture during
first molar removal (Case No. 1).
Stabilization of the
maxillary segment
Stainless steel arch bars and wire
or
Resin-bonded appliances for 4-6 weeks
Standard regimen
for oroantral
communication
Amoxicillin 500 mg every 8 hours for 7 days
(if patient is allergic to penicillin, prescribe clindamycin 300 mg every
6 hours for 7 days)
Pseudoephedrine 30 mg every 6 hours for 7 days
Oxymetazoline nasal spray (2 puffs per nostril) every 8 hours for 3 days
Analgesics as needed
Sinus precautions
and instructions
Instruct patient not to blow nose or cause excessive sinus pressure for
at least 3 weeks.
Consider referral to oral surgeon as needed.
Weekly follow-up visits are recommended to ensure proper healing.
maxillary dentures, a fractured tuberosity
should be preserved whenever possible,
and a referral to an oral and maxillofacial
surgeon is advised should a fracture occur.3
Most case reports in the literature report
that excessive, uncontrolled forces—and
not using a pinch grasp technique—can
result in a fracture of the maxilla.3,4 Dental
anomalies—such as tooth fusion, tooth
isolation, hypereruption, ankylosis, hypercementosis, chronic periapical infection,
sclerotic bone, divergent roots, abnormal
number of roots, multiple extractions and
early loss of teeth—may lead to infiltration
of the sinus into the alveolus, thus further
complicating extractions. If preoperative
radiographs indicate that the antrum compromises the bone surrounding the root
tips, a surgical technique that removes a
single root at a time is advised.5,6
If a large fracture of the maxillary alveolus takes place, immediate cessation of
the extraction is advised to avoid further
damage to the mucosal membrane, vasculature, musculature, or sinus and osseous
structures. Preservation and stabilization
by fixation of the fractured alveolus for
4-6 weeks is ideal.4,5 If the extraction must
be completed, surgical techniques—avoiding twisting and excessive movement of
the alveolus—are advised to preserve as
much of the bone as possible.4,5 To aid the
healing of the bone, occlusal adjustment
may be needed to prevent injurious occlusal forces of the teeth being fixated.4,5
If the tooth is infected or symptomatic
at the time of fracture, removal of the
infection source should still be accomplished. Doing so by conservative surgical means to maintain the alveolus and
its attachment to the periosteum will aid
healing.6,7 If this is not possible, removal
of the tooth and bone should be followed
by a watertight closure of the tissues.
After 4-6 weeks of healing, the area may
be grafted if deemed necessary.6,7
Postoperative instruction should
include avoiding forcible rinsing or any
nose-blowing for 2 weeks to prevent
oroantral fistula development. This
should be accompanied with an antibiotic regimen, nasal decongestants, and
anti-inflammatory analgesics. In the
authors’ experience, it is common for
light bleeding to occur from the ipsilateral nostril for 1-2 days. Radiographs
should be ordered 2 months postsurgery
to determine the adequacy of healing.
It is common to have radiopacity in
the affected maxillary sinus for a short
period of time.4,5 No further treatment
is needed unless symptoms of an infection arise. In rare cases, if the pterygoid
hamulus and tensor veli palatini are
disrupted, the collapse of the Eustachian
tube can cause decreased hearing acuity
on the ipsilateral side.4,5
The authors’ procedural recommendations for maxillary fracture during first
molar removal are listed in Table 1.
www.agd.org
Case No. 2
In order to prevent mandibular fracture
during extraction of a third molar, a thorough understanding of the population
at risk, common sites, risk factors, and
signs is necessary. Factors that may play a
role in mandibular fractures include the
magnitude of tooth impaction, angulation
of the tooth, size and shape of the roots,
age and gender of the patient, dentist’s
level of experience, presence of pathoses
and infection around the tooth, systemic
diseases, and medications that can affect
bone strength.8 When the amount of
force on the bone exceeds the strength
of that bone, a fracture will occur. Due
to less bony support, mandible fractures
occur 2-3 times more often than those of
other facial bones during routine dental
extractions.8 Long or bulbous roots,
hypercementosis, and multi-rooted teeth
can also be risk factors.9 The experience
level of the surgeon—as it relates specifically to management of the elevator—can
significantly impact the potential for
fracture. It is recommended that elevators be used in a rotational fashion rather
than a lever fashion.9 Pathoses such as
cysts, osteoporosis, ankylosis, and alveolar
atrophy can also contribute to fracture.9
Men >25 years of age are more at risk for
fracture, because their masticatory force is
inherently greater than that of women.9,10
Additionally, it has been found that fractures tend to occur more often on the left
side, as seen in this case. This is possibly
due to the decreased visualization on that
side by a right-handed operator.10 The
extent to which the tooth is impacted and
the portion of the mandibular volume
occupied by the tooth are also important
factors. The risk of fracture is higher
when the relative portion of the mandible
taken up by the third molar exceeds
50%.8 As seen in Figure 3, the third
molar in this case occupied >50% of the
volume of the mandibular bone.
If a fracture is suspected, a thorough
assessment to determine the severity of the
fracture must be performed. Radiographs
must be obtained to locate the fracture,
the occlusion must be assessed, and the
degree of mobility across the suspected
fracture must be established.9 After the
local anesthesia has worn off, the patient
should be checked for any altered sensations in the lip and/or chin.
General Dentistry
May/June 2015
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Exodontia Management of uncommon complications in seemingly routine oral surgeries
Table 2. Authors’ procedural recommendations for
mandibular fracture after third molar surgery (Case No. 2).
Table 3. Authors’ procedural recommendations for
maxillary third molar displaced into the infratemporal
space (Case No. 3).
Stabilization of
maxillary and
mandibular arches
Stainless steel arch bars and wire (for 6 weeks)
to ensure proper alignment and healing
Immediate
Alternatively, an open reduction with titanium
plates can be performed.
Radiographs
to locate
Cone beam computed tomography/computed tomography
Drug therapy
Amoxicillin 500 mg every 8 hours for 7 days
(if patient is allergic to penicillin, prescribe
clindamycin 300 mg every 6 hours for 7 days)
Drug therapy
Amoxicillin 500 mg every 8 hours for 7 days (if patient is
allergic to penicillin, prescribe clindamycin 300 mg every
6 hours for 7 days)
Close the flap.
Analgesics as needed
Instructions
Consider referral to oral surgeon as needed.
Weekly follow-up visits are recommended to
ensure proper healing.
A suggested measure to prevent postoperative fracture would be placing the
patient on a no-chew diet for the first
4 weeks.9,10 Lastly, the literature has
shown that the most common complication in the treatment of mandibular
fractures is postoperative infection.10
Therefore, a patient should be placed on
antibiotic therapy.
A survey done by Perry & Goldberg in
2000 questioned 106 oral and maxillofacial surgeons in Connecticut about their
experience with late mandibular fractures
over a 10-year period.11 The survey results
indicated that there is a low incidence of
postoperative fracture, occurring in only an
estimated 0.005% of impacted third molar
surgeries in the 10-year period covered.11
The extent of impaction plays a key role
in determining postoperative fracture. The
more deeply impacted the third molar, the
higher the risk for postoperative fracture.
Another risk factor for postoperative fracture is a history of preoperative infection.
Chronic or deep infections will decalcify
and destroy bone, potentially leading to
fractures.11 These fractures tend to occur
at a higher rate during postoperative days
8-21. As stated previously, it is important
to stress to the patient the importance of
a no-chew diet for a period for at least 4
weeks postsurgery.12
Patients should also be made aware of
the possibility of malocclusion, depending
on how well the segments heal and what
type of surgery was conducted.9 There
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May/June 2015
General Dentistry
Stop the surgery.
Plain film
Analgesics as needed
Instructions
Allow 3 weeks for healing to occur prior to attempted
re-entry and retrieval.
Consider referral to oral surgeon as needed.
can be loss of vitality in the teeth adjacent
to the fracture, parasthesia in the area
of the fracture, and possible infection
(such as osteomyelitis).9
The authors’ procedural recommendations for mandibular fracture after third
molar surgery are listed in Table 2.
Case No. 3
Although complications are rare in the
removal of impacted third molars by
oral and maxillofacial surgeons, tooth
displacement is a potential problem.13
Displacement into anatomical spaces—
such as the infratemporal fossa, pterygomandibular space, maxillary sinus,
buccal space, or the lateral pharyngeal
space—have all been reported in the
literature.14 Most often these are due to
insufficient clinical and radiographic
examinations, deficient anatomical and
surgical knowledge, inadequate flap
placement, limited site visibility, and
excessive or uncontrolled forces applied
during extraction.14 Multiple reports have
been published on the displacement of
third molars during surgery.13-15 Due to the
crucial anatomical structures in the head
and neck, retrieval of the foreign object by
a trained surgeon is advised.
In the case of a tooth displaced into the
infratemporal space, immediate retrieval
of the tooth may not be possible due to
poor visibility from the bleeding into the
area, poor flap design, and/or instability
of the tooth, even if the tooth is palpable
www.agd.org
extraorally.15 Restricted opening, localized
pain, swelling, and infection in the area
may occur if an antibiotic regimen is not
given to the patient following surgical
manipulation and displacement.16 Regimen
options include amoxicillin (500 mg every
8 hours for 1 week) or clindamycin (300
mg every 6 hours for 7 days). Waiting
3-4 weeks postsurgery for fibrous tissue
to form around the displaced tooth helps
stabilize and immobilize it, reducing the
risk of deeper displacement and damage
to other structures. Some clinicians believe
that the use of the masticatory muscles will
help a displaced tooth in the infratemporal
space to descend, making the removal
potentially less complicated.13 The decision
to wait to retrieve the displaced tooth must
be made by the patient after a thorough
treatment plan is presented.13
Prior to retrieval, the tooth should
be radiographically located, even if it is
palpable. CT or cone beam computed
tomography (CBCT) can give the most
accurate location of the object. Clinicians
are undecided about the most appropriate
approach for retrieval.11 Depending on
the surgeon, molar retrieval and removal
of granulation tissue may be performed in
various ways: via an incision in the buccal
sulcus, a classic subperiosteal flap (for third
molar extractions), the Gillies approach,
the Caldwell-Luc approach (after removal
of the posterior sinus wall), or via resection of the coronoid process. The decision
to perform the retrieval under general or
Table 4. Authors’ procedural recommendations for necrosis of maxillary soft
tissue after tuberosity fracture during third molar extraction (Case No. 4).
Stabilization of the
maxillary segment
Stainless steel arch bars and wire
or
Resin-bonded appliances for 4-6 weeks for immobilization during healing
Infection
If the tooth is significantly infected, removal of the tooth and bone is indicated
with the least soft tissue reflection possible; suture in a watertight fashion.
Standard regimen
for oroantral
communication
Amoxicillin 500 mg every 8 hours for 7 days (if patient is allergic to penicillin,
prescribe clindamycin 300 mg every 6 hours for 7 days)
Pseudoephedrine 30 mg every 6 hours for 7 days
Oxymetazoline nasal spray (2 puffs per nostril) every 8 hours for 3 days
Analgesics as needed
Sinus precautions
and instructions
Instruct patient not to blow nose or cause excessive sinus pressure for at least
3 weeks.
Consider referral to oral surgeon as needed.
Weekly follow-up visits are recommended to ensure proper healing.
local anesthesia is dependent upon the
patient and the location of the tooth.14
Postoperative nonsteroidal anti-inflammatory drugs, analgesics, and antibiotics are
prescribed to aid recovery.13,15,16
The authors’ procedural recommendations for a maxillary third molar displaced
into the infratemporal space—once the
tooth is no longer identifiable—are listed
in Table 3.
Case No. 4
Maxillary tuberosity fracture is more
common than one would expect with
molar extractions, especially third molars.
Etiological factors contributing to this
complication are large maxillary sinuses
with thin walls, sinus extension into the
maxillary tuberosity, and the projection
of root apices into the sinus cavity.4,5 It
has been recommended that such teeth
should be sectioned and removed 1 root at
a time.4 Other etiological factors include
teeth with large divergent roots, teeth
with a large or abnormal number of roots,
as well as dental anomalies such as tooth
fusion, tooth isolation, overeruption,
ankylosis, and hypercementosis.4 Chronic
apical infections of the molar can render
the bone of the tuberosity more liable to
fracture as well.4 Radiographic examination can aid in preoperative planning, as
well as identifying some of the etiological
factors listed above.5 The floor of the maxillary sinus can extend between adjacent
teeth and/or between roots; this creates an
elevation in the antral surface, referred to as
hillocks.5 This elevation causes a reduction
in the thickness of the sinus floor, making
an oroantral communication more likely.5
A major concern in a maxillary fracture is the vasculature of the area, which
increases the possibility of a hemorrhage.17
This life-threatening event can happen
in medically compromised patients with
a coagulopathy as well as in healthy
patients.17 The incidence of maxillary
tuberosity fracture is 0.6%.17 Management
of severe hemorrhage can require hospitalization and subspecialty care by an
interventional radiologist.
The potential for hemorrhage can be
understood by studying the anatomy of
the maxillary tuberosity region. The major
blood supply to the area is the maxillary artery.17 It traverses anteriorly and
obliquely past the lateral pterygoid muscle
before entering the pterygopalatine fossa.
Prior to entering the fossa, the posterior
superior alveolar artery branches off from
the maxillary artery and wraps around
the tuberosity, descending anteriorly and
inferiorly.17 There is also a buccogingival branch from the posterior superior
alveolar artery that approaches the infraorbital region of the maxilla, which may
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anastomose with the infraorbital artery.17
If the fracture were to extend posteriorly
and superiorly toward the pterygopalatine
fossa, damage could occur to branches of
the maxillary artery (descending palatine
artery; descending pharyngeal artery; sphenopalatine, infraorbital, and vidian arteries).17 Venous supply is provided by the
pterygoid venous plexus, located between
the medial and lateral pterygoid muscles as
well as the temporalis and lateral pterygoid
muscles.17 The plexus wraps around the
maxillary artery in order to protect it from
occlusion during mastication.17 There is an
intimate relationship between the vasculature and the overlying periosteum.17 In the
event of profuse bleeding during extraction
of a maxillary third molar, the key vessels
involved are the posterior superior alveolar
artery along with the tuberosity itself.17
When fracture of the tuberosity is suspected, it is important to stop any further
attempts at extracting the tooth, then
splint where necessary, and follow with a
prompt referral to an oral and maxillofacial surgeon.17 The goal of management
is to secure the fractured bone in place to
provide an ideal environment for healing;
if the segment cannot be stabilized, it
must be removed.4
It is recommended that the clinician discuss the potential of a tuberosity fracture
while obtaining patient consent.4 Routine
treatment for such a situation is stabilization with rigid fixation techniques for 4-6
weeks.4 Then, surgical extraction should
again be attempted.4 There are situations
in which the tooth is severely infected,
and leaving it in can be more problematic.
Removal is attempted via reflection of the
gingiva cuff while avoiding the separation of the periosteum from the fractured
tuberosity.4 If removing the tooth without
the tuberosity is unavoidable, the tissue
should be closed in a watertight fashion.4
Grafting of the area can then be accomplished after 4-6 weeks’ healing and an
antibiotic therapy regimen.4 In addition
to the usual postextraction instructions,
the patient must be advised to avoid blowing his/her nose for 3 weeks to prevent
oroantral communication (if one has
not already occurred).5 Antibiotics, nasal
decongestants, and anti-inflammatory
analgesics should be prescribed to prevent
development of a maxillary sinusitis.5 The
patient should avoid rinsing his/her mouth
General Dentistry
May/June 2015
e9
Exodontia Management of uncommon complications in seemingly routine oral surgeries
forcefully and be assured that bleeding
from the nostril on the affected side for
1-2 days is common.5 Sutures placed to
close the defect should be removed after
2 weeks, and a radiograph should be
taken 2 months postoperatively to determine healing.5
Oroantral communication complications are more common after the third
decade of life.5 Smaller defects of <5 mm
may close spontaneously, while larger
communications generally require surgery.5
Failure to diagnose and treat an oroantral
communication properly can lead to a
permanent epithelial tract.5
The most serious complication is deafness due to disruption of the pterygoid
hamulus and tensor veli palatine, causing
collapse of the Eustachian tube.5 Proper
preoperative radiographic interpretation and knowledge of the structures
involved are essential to understand
such complications.5
The authors’ procedural recommendations for necrosis of maxillary soft tissue
after tuberosity fracture during third molar
extraction are listed in Table 4.
unfamiliar with or unable to perform the
tasks required to remedy the situation.
It is important to remember that with
proper care, most severe complications
will heal and allow the patient to return
to function.
Author information
Mr. Salim and Mr. Newman are DDS
candidates, University of Colorado School
of Dental Medicine, Aurora, where
Dr. Closmann is an associate professor,
and Dr. Borris is an associate professor
and chairman, Division of Oral and
Maxillofacial Surgery, Department of
Surgical Dentistry.
References
Although severe complications in the
dental office are rare, they do occur, and
a general dentist needs to know how to
handle the situation. Even if all precautions are taken, complications may still
arise, and proper care of the patient is
essential.18 Referral to an oral surgeon
should be considered if the dentist is
1. Baniwal S, Paudel KR, Pyakurel U, Bajracharya M, Niraula SR. Prevalence of complications of simple tooth
extractions and its comparison between a tertiary center and peripheral centers: a study conducted over
8,455 tooth extractions. JNMA J Nepal Med Assoc.
2007;46(165):20-24.
2. Kim HJ, Yoon HR, Kim KD, et al. Personal-computerbased three-dimensional reconstruction and simulation of maxillary sinus. Surg Radiol Anat. 2002;24(6):
393-399.
3. Shah N, Bridgman JB. An extraction complicated by
lateral and medial pterygoid tethering of a fractured
maxillary tuberosity. Br Dent J. 2005;198(9):543-544.
4. Polat HB, Ay S, Kara MI. Maxillary tuberosity fracture
associated with first molar extraction: a case report.
Eur J Dent. 2007;1(4):256-259.
5. Chrcanovic BR, Freire-Maia B. Considerations of maxillary tuberosity fractures during extraction of upper
molars: a literature review. Dent Traumatol. 2011;
27(5):393-398.
6. Altug HA, Sahin S, Sencimen M, Dogan N. Extraction
of upper first molar resulting in fracture of maxillary
tuberosity. Dent Traumatol. 2009;25(1):e1-e2.
e10
www.agd.org
Conclusion
May/June 2015
General Dentistry
7.Fonseca RJ. Oral and Maxillofacial Surgery, Vol 1.
Philadephia: W.B. Saunders; 2000.
8. Cankaya AB, Erdem MA, Cakarer S, Cifter M, Oral CK.
Iatrogenic mandibular fracture associated with third
molar removal. Int J Med Sci. 2011;8(7):547-553.
9. Lapointe H. How do I manage a mandible fracture
during extraction? J Can Dent Assoc. 2013;79:d27.
10. Duarte BG, Assis D, Ribeiro-Junior P, Goncales ES. Does
the relationship between retained mandibular third
molar and mandibular angle fracture exist? An assessment of three possible causes. Craniomaxillofac Trauma Reconstr. 2012;5(3):127-136.
11. Perry PA, Goldberg MH. Late mandibular fracture after
third molar surgery: a survey of Connecticut oral and
maxillofacial surgeons. J Oral Maxillofac Surg. 2000;
58:858-861.
12. Woldenberg Y, Gatot I, Bodner L. Iatrogenic mandibular fracture associated with third molar removal. Can it
be prevented? Med Oral Patol Oral Cir Bucal. 2007;
12(1):E70-E72.
13. Selvi F, Cakarer S, Keskin C, Ozyuvaci H. Delayed removal of a maxillary third molar accidentally displaced
into the infratemporal fossa. J Craniofac Surg. 2011;
22(4):1391-1393.
14. Ozer N, Ucem F, Saruhanoglu A, Yilmaz S, Tanyeri H.
Removal of a maxillary third molar displaced into pterygopalatine fossa via intraoral approach. Case Rep
Dent. 2013;392148.
15. Gomez-Oliveira G, Arribas-Garcia I, Alvarez-Flores
M, Gregoire-Ferriol J, Martinez-Gimeno C. Delayed
removal of a maxillary third molar from the infratemporal fossa. Med Oral Patol Oral Cir Bucal. 2010;
15(3):e509-e511.
16. Kocaelli H, Balcioglu A, Erdem TL. Displacement of a
maxillary third molar into the buccal space: anatomical
implications apropos of a case. Int J Oral Maxillofac
Surg. 2011;40(6):650-653.
17.Bertram AR, Rao AC, Akbiyik KM, Haddad S, Zoud K.
Maxillary tuberosity fracture: a life-threatening
haemorrhage following simple exodontia. Aust Dent
J. 2011;56(2):212-215.
18. Hupp, JR, Tucker MR, Ellis E. Contemporary Oral and
Maxillofacial Surgery. 5th ed. St. Louis: Mosby Elsevier;
2008:204.
Case Presentations
Unusual cases of transmigrated mandibular canines
Lata Goyal, MDS
This case series also highlights the importance of early diagnosis for the
interceptive treatment of transmigration.
Received: June 24, 2013
Revised: December 2, 2013
Accepted: December 16, 2013
Transmigration, an extremely rare anomaly that happens almost
exclusively with mandibular canines, is defined as a pre-eruptive
migration across the midline. It can lead to various restorative, surgical,
orthodontic, and interceptive problems. This condition usually is not
related to any painful symptoms and cannot be detected on clinical
examination. This article presents 3 cases of transmigration. In 1 case,
the right canine was involved, which is considered to be especially rare.
T
ransmigration refers to pre-eruptive
migration of a tooth across the midline.1 This rare phenomenon occurs
almost exclusively in mandibular canines.
Although the term was first coined in
1964, it was a 1971 study by Tarsitano et
al that defined it as the phenomenon of an
unerupted mandibular canine crossing the
midline.2,3 A 1985 article by Javid stated
that in a true transmigration, the midline
had to be crossed by half of the tooth.1
But rather than the distance of migration,
a canine’s tendency to cross the barrier of
the mandibular midline suture is a more
important factor to be considered.4
A 2002 article by Mupparapu used
5 criteria to classify transmigrated canines
based on their position within the jaw
when first diagnosed and their migratory
pattern.5 In cases of Type 1 transmigration,
the canine is positioned mesioangularly
across the midline within the jaw bone,
labial or lingual to anterior teeth, with the
Key words: transmigration, impaction, migration, mandibular canine
in the maxilla.7 While various theories
concerning the etiology of transmigration
have been suggested, the most accepted is
an abnormal displacement of the dental
lamina in embryonic life.8 This condition
usually is not related to any painful symptoms and cannot be detected on clinical
examination; rather, it is best diagnosed by
a panoramic radiograph.9
This article describes 3 clinical cases of
transmigration (including the rarer Types
4 and 5) involving impacted mandibular
canines and highlights the importance of
using an orthopantogram (OPG) in cases
involving “missing” canine teeth, so that
interceptive treatment can position the
transmigrated canine correctly.
crown portion of the tooth crossing the
midline. In cases of Type 2 transmigration,
the canine is impacted horizontally, near
the inferior border of the mandible and
below the apices of the incisors. In Type 3,
the canine erupts either mesial or distal
to the opposite canine. With Type 4, the
canine is impacted horizontally near the
inferior border of the mandible below the
apices of either the premolars or molars on
the opposite side. In Type 5, the canine is
positioned vertically in the midline (the
long axis of the tooth crossing the midline), regardless of eruption status.5 (Fig. 1)
Types 1-5 define the most common
locations for transmigrated canine teeth,
although some unusual positions have
been reported, including reverse oblique
migration of the mandibular canine, which
crossed the midline and pierced the lower
border of the mandible.6 Transmigration
is much more common in mandibular
canines; some instances have been reported
1
5
3
Case No. 1
A 25-year-old man presented with the chief
complaint of “dirty teeth.” Clinical examination revealed the missing right mandibular canine. A panoramic radiograph showed
4
2
Fig. 1. Diagrammatic representation of Types 1-5 transmigration in Mupparapu’s classification system.
www.agd.org
General Dentistry
May/June 2015
e11
Case Presentations Unusual cases of transmigrated mandibular canines
Fig. 2. Case No. 1. Panoramic radiograph showing a Type 1
transmigration of the mandibular right canine.
Fig. 3. Case No. 2. Panoramic radiograph showing a Type 4 transmigration of the mandibular
left canine.
an impacted canine crossing the midsagittal
plane in a mesioangular direction; thus
it was classified as a Type 1 transmigration (Fig. 2). This condition was left
untreated as the patient was asymptomatic;
however, he agreed to return for periodic
follow-up appointments.
Case No. 2
A 35-year-old man presented for orthodontic treatment to close spacing
between the mandibular anterior teeth.
Clinical examination showed the spacing
between the mandibular anterior teeth
as well as the absence of the permanent
mandibular left canine. A panoramic
radiograph was taken, which revealed
the impacted tooth. The impaction was
categorized as a Type 4 transmigration,
as it crossed the midline and impacted
near the inferior border of the mandible,
below the apices of the premolar (Fig. 3).
There was no abnormal pathological
change detected in the radiograph. The
patient was informed of this condition
and scheduled for routine checkup procedures. No treatment was recommended
because the patient was asymptomatic.
Case No. 3
A 27-year-old man was referred to have
his retained primary teeth extracted.
Intraoral radiographs and clinical examination showed the retained primary teeth
and the coronal portion of an impacted
tooth. The patient was asked to return for
a panoramic radiograph, which showed
an unerupted impacted mandibular
left canine tooth, classified as a Type 5
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May/June 2015
General Dentistry
Fig. 4. Case No. 3. Panoramic radiograph showing a Type 5 transmigration of the mandibular left canine.
transmigration (Fig. 4). Regular follow-up
appointments were planned; unfortunately, the patient did not return (Table).
Discussion
Although the etiology of transmigration
is still not clear, many hypotheses have
been proposed. One commonly accepted
theory involves the abnormal deviation
or displacement of a tooth bud during
its developmental period.1 Other contributing factors may include genetics,
premature loss or late retention of primary
canine teeth, an interrupted path of eruption, osteodental discrepancies, odontomas, cysts, and tumors.7,9,10
Transmigration should be suspected
when the mandibular canine is absent
from the arch and has not erupted more
than a year after the normal age of eruption or when there is a deviation from
the midline. In some cases, transmigration has been associated with agenesis of
the lateral incisors and lower premolars,
www.agd.org
proclined lower incisors, and deviated
dental midlines.2,11 When any of these
factors are present, the patient must be
evaluated radiographically.
Transmigration can be predicted by
examining canine tooth germ inclination.4 If the angle formed by the midsagittal plane and the dental axis exceeds
50 degrees, transmigration is indicated.
An angle of 30-50 degrees indicates possible transmigration. When the angle is
less than 30 degrees, transmigration is
unlikely.4 A 2003 article by D’Amico et
al suggested that canines that lie between
30 and 40 degrees tend to cross the
midsagittal plane, and when the angle
exceeds 50 degrees, an impacted canine
becomes displaced.8
According to Vichi & Franchi,
proclination of the mandibular incisors increases the axial inclination of
unerupted canines, and the symphyseal
cross-sectional area of the chin could play
a role in the transmigration mechanism.11
Table. Characteristics of cases of transmigration reported in this study.
Case No.
Age
Sex
Tooth No.
Location
Inclination
Migrated position
Type*
1
25
Male
27
Alveolar process
Oblique
22-23
1
2
35
Male
22
Inferior border of mandible
Horizontal
28-29
4
3
27
Male
22
Midline
Vertical
24-25
5
Note: Transmigration type based on the Mupparapu classification system.
5
Yavuz et al classified mandibular canines
according to their angulations and depth
of involved teeth.12 The present report
was based on the behavior patterns
of impacted canines as described by
Mupparapu based on migratory paths.5
The first case reported in this article was
a Type 1 transmigration with a mesioangular position below the anterior teeth
and a coronal portion crossing the midline. Type 1 is the form most commonly
reported in the literature; however, case
No. 1 was a rare example of right canine
transmigration.1,2,7,12,13
In the second case report, the mandibular canine was transmigrated and
appeared in a very rare horizontal position, making it a Type 4; only 0.13% of
transmigration cases are reported as this
type.5 This finding confirms Thoma’s
1952 statement that a horizontally positioned transmigrated mandibular canine
is very unusual.13
In the third case report, the canine
was positioned vertically in the midline;
thus it was classified as a very rare Type 5
transmigration.
Transmigration is more common in
mandibular canines than in maxillary
canines because of the strong eruptive
forces that direct the crown through
the dense mandibular symphysis to the
other side.14 It is difficult to determine
the prevalence of the phenomenon as
the literature consists largely of isolated
case reports. A 2004 study by Aydin et
al reviewed 4500 panoramic radiographs
and identified 14 transmigrant canines
(0.3%).7 More recently, a 2010 study
by Vuchkova & Farah reviewed 60,000
OPGs over a period of 6 years and found
only 4 cases.15 That same year, Aktan et
al studied 5000 OPGs in a Turkish population and found 20 transmigrated mandibular canines in 17 patients (0.34%).16
Treatment for transmigration depends
on tooth position, eruption, angulation
of tooth at the time of diagnosis, stage
of development, and distance of migration. Interceptive treatment is most
successful when transmigration is found
in patients 8-9 years of age.4 The early
age of these patients provides a greater
number of treatment options, the most
suitable involving surgical repositioning
and autotransplantation. Surgical repositioning should ideally be performed
when the root length of the tooth is
50%-75% complete. The length of time
between removal and reinsertion should
be minimal to prevent necrosis of the
periodontal ligament, which can cause
resorption and ankylosis.4 Verma et al
reported a successful instance in which a
transmigrated mandibular right canine
was transplanted into the prepared
socket of a retained primary canine;
however, external root resorption has
also been observed.4,17
A transmigrated canine that is
detected early can be exposed surgically
and corrected by means of orthodontic
traction.18,19 A 2012 article reported that
orthodontic traction was used successfully to treat a case in which a transmigrated mandibular left canine had its
crown below the apices of the right central incisor.20 Trakyali et al reported how
a transmigrated mandibular right canine
was aligned orthodontically, followed by
recontouring to simulate a lateral incisor.21 In general, once transmigration is
established, the most favored treatment
is the extraction of the impacted tooth.
However, if patients are asymptomatic,
regular observation and periodic radiographic assessment is the recommended
treatment option.4 In the present cases,
all 3 patients were asymptomatic with
no associated pathological condition or
www.agd.org
abnormality detected during clinical or
radiographic examination. In each case,
the condition was left untreated and
regular follow-up visits were scheduled.
Conclusion
It is rare for an impacted maxillary or
mandibular canine to migrate through the
midline. A thorough clinical checkup and
proper investigation (including panoramic
radiographs) is necessary to detect the
position of migrated and impacted teeth.
Additional research should be conducted
to determine the etiology and treatment
modality of such an unusual condition.
Early diagnosis is important for preventing
more complicated situations.
Author information
Dr. Goyal is a senior resident, All India
Institute of Medical Sciences, Rishikesh,
Uttarakhand, India.
References
1. Javid B. Transmigration of impacted mandibular cuspids. Int J Oral Surg. 1985;14(6):547-549.
2. Ando S, Aizawa K, Nakashima T, Sanka Y, Shimbo K,
Kiyokawa K. Transmigration process of the impacted
mandibular cuspid. J Nihon Univ Sch Dent. 1964;6:
66-71.
3. Tarsitano JJ, Wooten JW, Burditt JT. Transmigration of
nonerupted mandibular canines: report of cases. J Am
Dent Assoc. 1971;82(6):1395-1397.
4. Joshi MR. Transmigrant mandibular canines: a record
of 28 cases and a retrospective review of the literature. Angle Orthod. 2001;71(1):12-22.
5. Mupparapu M. Patterns of intra-osseous transmigration and ectopic eruption of mandibular canines: review of literature and report of nine additional cases.
Dentomaxillofac Radiol. 2002;31(6):355-360.
6. Umashree N, Kumar A, Nagaraj T. Transmigration of
mandibular canines. Case Rep Dent. 2013;2013:
697671.
7. Aydin U, Yilmaz HH, Yildirim D. Incidence of canine impaction and transmigration in a population. Dentomaxillofac Radiol. 2004;33(3):164-169.
8. D’Amico RM, Bjerklin K, Kurol J, Falahat B. Long-term
results of orthodontic treatment of impacted maxillary
canines. Angle Orthod. 2003;73(3):231-238.
General Dentistry
May/June 2015
e13
Case Presentations Unusual cases of transmigrated mandibular canines
9. Madiraju GS, Rao KS, Singamaneni V. A rare case
of transmigration of mandibular canine associated
with an odontoma. BMJ Case Rep. 2013;24:2013.
10. Camilleri S, Scerri E. Transmigration of mandibular canines—a review of the literature and a report of five
cases. Angle Orthod. 2003;73(6):753-762.
11.Vichi M, Franchi L. The transmigration of the permanent lower canine [in Italian]. Minerva Stomatol.
1991;40(9):579-589.
12. Yavuz MS, Aras MH, Buyukkurt MC, Tozoglu S. Impacted mandibular canines. J Contemp Dent Pract. 2007;
8(7):78-85.
13. Thoma KH. Oral Surgery. 2nd ed. St. Louis: CV Mosby;
1952.
14. Sutton PR. Migration and eruption of non-erupted
teeth: a suggested mechanism. Aust Dent J. 1969;
14(4):269-270.
15. Vuchkova J, Farah CS. Canine transmigration: comprehensive literature review and report of 4 new Australian cases. Oral Surg Oral Med Oral Pathol Oral Radiol
Endod. 2010;109(4):e46-e53.
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May/June 2015
General Dentistry
16. Aktan AM, Kara S, Akgunlu F, Malkoc S. The incidence
of canine transmigration and tooth impaction in a Turkish subpopulation. Eur J Orthod. 2010;32(5):575-581.
17. Verma SL, Sharma VP, Singh GP. Management of a
transmigrated mandibular canine. J Orthod Sci. 2012;
11(1):23-28.
18. Wertz RA. Treatment of transmigrated mandibular canines. Am J Orthod Dentofacial Orthop. 1994;106(4):
419-427.
19. Mazinis E, Zafeiriadis A, Karathanasis A, Lambrianidis
T. Transmigration of impacted canines: prevalence,
management and implications on tooth structure and
pulp vitality of adjacent teeth. Clin Oral Investig.
2012;16(2):625-632.
20. Kumar S, Urala AS, Kamath AT, Jayaswal P, Valiathan A.
Unusual intraosseous transmigration of impacted
tooth. Imaging Sci Dent. 2012;42(1):47-54.
21. Trakyali G, Cildir SK, Sandalli N. Orthodontic treatment
of a transmigrated mandibular canine: a case report.
Aust Orthod J. 2010;26(2):195-200.
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Pediatric Dentistry
Clinical outcomes of indirect composite
restorations for grossly mutilated primary
molars: a clinical observation
Neeti Mittal, BDS, MDS n Binita Srivastava, BDS, MDS
This study was conducted to report the clinical outcomes and the parental
and child satisfaction of onlays for restoring mutilated primary molars.
Twenty subjects, ages 3-8 years, with the presence of at least 1 mutilated
primary molar (≥3 carious surfaces and a carious surface area ≥3/4 of the
occlusal surface) were recruited. This study assessed the clinical success,
gingival health, and parent/child satisfaction of 28 indirect composite
onlays. The onlays showed a 100% retention rate at 12 months follow-up
and a marginal integrity of 96.43%. High rates of satisfactory Alpha
ratings for color stability (92.86%), surface texture (92.86%), and
anatomic form (100%), coupled with significant improvements in gingival
A
lthough preventive dentistry is
remarkably successful, a sizeable
section of the pediatric population
presents at high risk for caries with grossly
decayed dentition.1 In such cases, pediatric
dentists are responsible not only for restoring the function and esthetics of the teeth
but also the self-esteem of these young children to prevent an unpleasant appearance
as well as avoid future negative psychological sequelae due to the patient’s self-image.
Gone are the days when the desire to look
good was the privilege of adults only;
today, even young children are demanding
better looking white restorations.2
health of the restored teeth (P < 0.05), were reported. Indirect composite
onlays successfully restored anatomic form and function of the grossly
decayed primary molars—with shorter chairside times—while satisfying
the esthetic demands of the young pediatric patients.
Received: December 3, 2013
Revised: May 9, 2014
Accepted: June 5, 2014
Esthetic alternatives to stainless steel
crowns (SSCs), the gold standard restorative modality for mutilated posterior
primary teeth, include celluloid strip
crowns, indirect composite restorations,
open-faced stainless steel crowns, and
preveneered stainless steel crowns.3-6
These alternatives, although esthetically
more acceptable, are still not ideal, owing
to their requirements for long chairside
times. Furthermore, commercially available preveneered crowns are sometimes
difficult to fit, and the esthetic material
has a tendency to fracture and/or chip off
during contouring and crimping.
Fig. 1. Preoperative intraoral view of a pediatric patient with
grossly decayed teeth No. 11d and 20d and a defective restoration
in tooth No. 19d.
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May/June 2015
General Dentistry
Key words: grossly decayed molars, esthetics, indirect
composite onlays, mutilated molars, primary teeth
www.agd.org
Rehabilitation with various types of direct
restorations, although providing satisfactory esthetics, can sometimes be problematic in a young child with behavioral issues.
On the other hand, indirect restorations
can still be performed due to their shortened chairside times. Additional clinical
benefits include precise marginal integrity,
wear resistance, ideal proximal contacts,
and excellent anatomic morphologies.7-9
To date, only a few isolated case reports
have been published describing indirect
composite restorations in primary teeth.
Keeping this dearth of information in
mind, we conducted this trial to report
Fig. 2. Final preparation of the mandibular molars. Note the flat
circumferential margin and smooth layer of the glass ionomer
compound at the floor of the pulp chamber to seal the
root canal orifices.
Fig. 3. Final impression of the mandibular molars.
on the clinical outcomes and acceptability
of indirect composite onlays in primary
molars in children.4,10,11
Materials and methods
Study design and setting
The present clinical trial was conducted
in the Pediatric and Preventive Dentistry
Department of the Santosh Dental College
and Hospital, Santosh University, India.
The study was approved by the review
board of the university’s ethics committee.
Source of data
A total of 20 children (3-8 years of
age) who presented to the outpatient
unit of the Pediatric and Preventive
Dentistry Department were included in
this evaluation.
Criteria for selection of participants
Inclusion criteria consisted of the presence
of ≥1 grossly decayed primary molar that
was not likely to exfoliate within 2 years
of the cementation of the restoration and
had >2/3 of the root length present when
observed on a periapical radiograph. Only
those teeth with ≥3 carious surfaces and
a carious surface area ≥3/4 of the occlusal
surface were included (Fig. 1). Exclusion
criteria included children with intellectual
and/or learning disabilities, abnormal
parafunctional habits (such as bruxism),
or primary molars with missing antagonists/adjacent contact teeth, or any child
that reported issues with mobility, sinuses,
abscesses, or tenderness. Failure to obtain
informed consent from the parents for
Fig. 4. Model with individual dies of the mandibular molars.
any reason also resulted in exclusion
from this trial.
Operative procedure
All clinical and laboratory steps were performed by a single operator.
Phase I
Complete caries removal was completed,
and areas in proximity to the pulp were
protected by applying calcium hydroxide
(Dycal, DENTSPLY International), followed by a glass ionomer cement (GIC)
(GC Fuji II Glass Ionomer Restorative,
GC America, Inc.). In the cases of nonvital
teeth, pulpectomies were performed, followed by obturation with calcium hydroxide (ApexCal, Ivoclar Vivadent, Inc.). A 1
mm thick lining of the GIC was applied
to seal the obturating material on the
floor of the pulp chamber. Nonretentive
withdrawal forms were established by
smoothing all internal walls and rounding off all internal line angles. Shoulder
finish lines with rounded internal angles
were established, resulting in butt joints,
such as a 90 degree cavosurface line angle,
using a round-end cylindrical diamond.
All internal walls were diverged from 5 to
15 degrees with no undercuts, using the
round-end tapered diamond held parallel
to the long axis of the tooth (Fig. 2).
Following preparation, impressions were
made with a 2-step putty wash technique
using a polyvinyl siloxane (PVS) impression material (Fig. 3). First, an impression
was made with putty using a preselected
stock tray with tray adhesive applied over
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it. Then the impression was trimmed via
the removal of interdental septa to create
space for a light body impression material. Teeth were thoroughly isolated using
high volume suction. The PVS impression
material was spread over the prepared
tooth surfaces, and the previous impressions were seated over them.
Temporization was done using GIC.
GIC was chosen as the temporary restorative material as it is capable of maintaining its integrity between scheduled
appointments while allowing for easy
removal when needed.
Shade selection was conducted in
natural light on wet tooth surfaces (as
the shade of desiccated teeth is lighter
than that of wet ones). Shade selections
for dentin were done by examining the
center of each tooth, while shade selections for enamel shades were done by
examining the proximal/cusp-tip region
of each tooth. These were approximated with the central portion of the
VITASPAN Classical (Sirona Dental
Systems, Inc.) tooth tab.
Phase II
In the laboratory, impressions were poured
in die stones, and working models were
made. Dies were separated with a saw
to facilitate the fabrication of the onlays
(Fig. 4). Cavity margins were marked in
lead pencil, and cyanoacrylate separating
media was applied.
Onlays were fabricated with Filtek
Z350 XT Supreme Universal Restorative
composite material (3M ESPE) using an
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May/June 2015
e17
Pediatric Dentistry Clinical outcomes of indirect composite restorations for grossly mutilated primary molars
Fig. 5. Onlays seated on the cast of the mandibular molars.
Fig. 6. Final postoperative view of the mandibular molars.
Table 1. United States Public Health Services (USPHS) modified criteria.12
Criteria
Alpha
Bravo
Charlie
Color stability
Restoration matches adjacent
tooth color.
Slight mismatch between restoration
and tooth color
Strong mismatch between
restoration and tooth color
Retention
No loss of restoration
Partial loss or mobile restoration
Complete loss of restoration
Marginal integrity
Explorer does not catch,
and/or no crevice is visible.
Explorer catches, and crevice is visible; Explorer penetrates crevice
however, no exposure of dentin, and
defect and extends to dentin.
restoration is not mobile.
Recurrent caries
No caries present
Anatomic form
Restoration is continuous with
existing anatomic form.
Surface texture
Texture similar to polished enamel Surface texture gritty
Postoperative sensitivity No complaint at all
incremental technique to carefully match
anatomic form, proximal contact, and
occlusion with opposing teeth (Fig. 5).
The dentin shade was used for core buildup, and the enamel shade was used in a
thickness of ≥1-2 mm. A thinner enamel
shade layer was used in the cervical
regions; a thicker layer was used in the
incisal areas. Curing was done per manufacturer’s instructions, using an EzeeCure
LED light (Unicorn DenMart) at 1200
mW/cm2. Occlusions were checked
using thin articulating paper by occluding with an opposing cast, followed by
adjustments if required.
The finishing and polishing of margins
was done using composite finishing and
polishing tips (CompoSite Finishing Kit
and CompoSite Polishing Kit, Shofu
Dental Corporation).
e18
May/June 2015
General Dentistry
Delta
Restoration is
fractured, mobile,
or missing.
Caries present and associated
with restoration
Restoration is discontinuous, but
missing material is not sufficient to
expose dentin.
Minor occasional complaint
Sufficient material lost to
expose dentin
Coarse surface pitting
Persistent pain, removal required
Phase III
After removing the temporary restorations, onlays were checked for proper
seating, marginal seal, and occlusion.
Occlusion was checked in centric as well
as eccentric positions. The internal surfaces of the onlays and the prepared teeth
were acid etched with 35% phosphoric
acid (3M ESPE) for 30 and 15 seconds,
respectively. Prior to etching, circumferential mushroom undercuts were placed
in the dentin just above the GIC layer
using a round-end diamond.
Cementation was done with dual cure
resin cement (RelyX U100 Self-Adhesive
Resin Cement, 3M ESPE), per manufacturer’s instructions (Fig. 6). Excess
cement was removed using an explorer
(floss for proximal surfaces). The final
finishing and polishing of margins were
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done using the same composite finishing
and polishing tips used in Phase II.
Evaluation criteria
All the recordings were done by a blind
observer who was unaware of the elapsed
time period after the cementation of the
restoration (such as at baseline or during
follow-up).
The clinical success of indirect composite onlays was assessed in accordance
with the modified United States Public
Health Services (USPHS) criteria at
baseline and at 1, 6, and 12 months
follow-up.12 Restorations were rated for
the following clinical parameters: color
stability, retention, marginal integrity,
recurrent caries, anatomic form, surface
texture, and postoperative sensitivity.
Each of these clinical parameters was
Table 3. Evaluation of onlays (n = 28) according to USPHS criteria at baseline
and 1, 6, and 12 months follow-up.
Table 2. Distribution of
sample according to type
of molar restored.
Type of
molar
Follow-up
Baseline
Number of
restorations Total
Maxillary
first
3
Maxillary
second
1
28
B
C
D
A
B
C
D
Color stability
28
0
0
NA
28
0
0
Retention
28
0
0
NA
26
0
2
Marginal integrity 28
B
C
D
A
B
C
D
NA
27
1
0
NA
26
2
0
NA
NA
28
0
0
NA
28
0
0
NA
0
0
0
26
0
0
2
28
0
0
0
27
1
0
0
28
NA
0
NA
28
NA
0
NA
28
NA
0
NA
28
NA
0
NA
Anatomic form
28
0
0
NA
28
0
0
NA
28
0
0
NA
28
0
0
NA
28
0
0
NA
28
0
0
NA
28
0
0
NA
26
2
0
NA
28
0
0
NA
28
0
0
NA
28
0
0
NA
28
0
0
NA
6
Mandibular
second
18
Postoperative
sensitivity
Abbreviations: A, Alpha; B, Bravo; C, Charlie; D, Delta; NA, not applicable.
Table 4. Satisfaction with onlays
at 12-month follow-up.
Parental satisfaction
Mean (SD)
Crown appearance
5.00 (0.000)
Shape
5.00 (0.000)
Size
5.00 (0.000)
Color
4.70 (0.923)
Durability
4.80 (0.616)
Cost
3.80 (1.196)
Child satisfaction
Overall appearance
12 months
A
Recurrent caries
Mandibular
first
Criteria
6 months
A
Surface texture
Criteria
1 month
Criteria
Mean (SD)
4.85 (0.366)
Abbreviation: SD, standard deviation.
Table 5. Comparative statistics at baseline versus follow-up at 12 months.
Characteristic
Baseline (SD)
12 months (SD)
P valuea
Gingival index
0.75 (0.639)
0.00 (0.000)
0.000b
a
Calculated using paired t test. bDenotes highly significant P value. Abbreviation: SD, standard deviation.
Parental satisfaction
Parental satisfaction was recorded for
various parameters such as crown appearance, shape, size, color, durability, and
cost. Each of these criteria was scored
using the following scale: 1 = very dissatisfied, 2 = dissatisfied, 3 = neutral,
4 = satisfied, and 5 = very satisfied.13
Parental satisfaction was assessed by a
questionnaire administered by the lead
author of this study.
graded using the code designations (in
decreasing order): Alpha, Bravo, Charlie,
and Delta.12 The descriptions of the ratings are summarized in Table 1.
Child satisfaction
A visual analogue scale was used to evaluate
each child’s satisfaction with scores ranging from 1 to 5 where 1 = poor, 2 = fair,
3 = good, 4 = very good, and 5 = excellent.14
Gingival health
Gingival bleeding was scored as 0 = no
bleeding, 1= bleeding on probing, and
2 = spontaneous bleeding. The mean gingival bleeding scores for each tooth to be
restored were recorded at the baseline and
12 months postoperatively.
Statistical analysis
Data were entered into an Excel
spreadsheet (Microsoft) and imported
into SPSS 16.0 software (SPSS, Inc.).
A Kolmogorov-Smirnov test was used
to determine the normality prior to
analysis. Data were expressed as mean and
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standard deviation (SD). A paired t test
was used for a comparative analysis of the
gingival health at the baseline and during
follow-up. A P value of <0.05 was considered to be significant.
Results
Eleven boys and 9 girls with a mean age
of 6.35 ± 1.357 years were enrolled in this
trial. A total of 28 (range: 1-4/subject)
indirect composite onlays were placed. The
majority of the onlays (18/28, 64.29%)
were placed in the primary mandibular
second molar (Table 2).
At baseline, 100% of the onlays had
Alpha ratings for all evaluated parameters
per the USPHS criteria (Table 3). At
1-month postoperative follow-up, 2 onlays
had fallen out but had been recovered
by the patients and were returned to the
clinic. These were recemented and were
not excluded from further evaluation. At
12 months follow-up, 7.69% of the onlays
exhibited Bravo ratings for color stability
and surface texture. A slight catch with an
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May/June 2015
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Pediatric Dentistry Clinical outcomes of indirect composite restorations for grossly mutilated primary molars
explorer was noticed in 1 (3.57%) of the
onlays. For all other parameters, 100% of
the onlays exhibited Alpha ratings.
Regarding parental satisfaction, higher
scores (5.00 ± 0.000) were observed for
crown appearance, shape, and size among
all the parameters scored (Table 4). The
lowest parental satisfaction scores were
reported for the cost (3.80 ± 1.196).
A statistically significant improvement
was seen in the gingival health of the
restored teeth (P = 0.000) (Table 5).
Discussion
The indirect composite onlays showed a
100% retention rate at 12 months followup and a marginal integrity of 96.43%.
As such, the results from this preliminary
observation are encouraging. High rates of
satisfactory Alpha ratings for color stability
(92.86%), surface texture (92.86%), and
anatomic form (100%), coupled with significant improvement in the gingival health
of the restored teeth, lend support for the
use of indirect composite onlays as a successful mode of esthetic rehabilitation for
grossly mutilated primary posterior teeth.
For mutilated posterior teeth postpulpectomy, various restorative modalities
include multisurface restorations (such
as amalgam, GIC, or composite) and
stainless steel crowns.15,16 Significantly
greater success rates have been reported
for stainless steel crowns as compared to
the abovementioned multisurface restorations.15,16 However, 1 obvious disadvantage
is their poor esthetic appearance, owing to
the metallic appearance that many patients
and parents find unacceptable.2,17 Also, the
poor adaptation of stainless steel crowns
can result in a compromised periodontium.
Esthetic alternatives to preformed stainless
steel crowns include open-faced stainless
steel crowns and preveneered stainless steel
crowns. Although these options provide
durability, marginal adaptation, and restoration of the morphological form and anatomy comparable to stainless steel crowns,
an obvious disadvantage is the high rate
of chipping of their veneers, resulting in
poor esthetic appearance.18
Direct composite restorations also
provide satisfactory esthetics, but their use
is limited to smaller cavities. Moreover,
it is very challenging to restore proper
anatomic form and contour along with
marginal adaptation in severely decayed
e20
May/June 2015
General Dentistry
primary molars by direct techniques for
children demonstrating questionable
compliance. Furthermore, direct composite restorations have been associated with
postoperative pain due to the contraction
of the resin that is bonded to thin cavity
walls, marginal microleakage following
polymerization shrinkage—especially
at the cervical cavosurface margins—
improper contact points, and relatively
low wear resistance.7-9,19 The extraoral
improved curing of the composite resin as
used in the present study can minimize
the abovementioned disadvantages of
direct composite restorations.9
Despite the availability of a variety of
specific systems for laboratory-processed
indirect composites, we used the composite material that is currently routinely
used for direct restorative procedures in
the clinic used in this study, and curing
was done with the same light-curing unit
generally used for direct composite restorations. Commercially available indirect
systems have greater filler loading for
improved mechanical strength and better
handling properties than direct composites, but these systems pose a greater
economic burden due to their higher
costs. Furthermore, these indirect systems
were developed for permanent teeth that
have to serve in the oral cavity for a much
longer period of time than primary teeth.
Moreover, the prime objective of this
study was to test the indirect composite
technique and not the specific material.
For these reasons, the authors prefer to
use direct composite material.
The successful execution of high quality restorative care in young patients
is often impeded by anxious and
uncooperative behavior. Decreases in
chairside time for restorative procedures
would result in more satisfied pediatric
patients and their caretakers. However,
longer chairside times might be required
to restore multiple mutilated primary
molars. To restore grossly broken posterior teeth with little remaining tooth
structure, the first step is to carry out a
core build-up, followed by a restoration
of the crown superstructure. Instead of
this 2-step technique, we used a 1-step
technique in which the core and crown
superstructure were built as a single
unit, thus reducing the chairside time.
Furthermore, multiple teeth can be
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restored simultaneously with this technique. However, 1 disadvantage of this
technique is the requirement of 2 visits
versus 1 visit, resulting in more effort on
the parts of both patients and parents.
However, for posterior teeth, it is not
always feasible to fabricate single-unit
indirect composite onlays. For adequate
retention, at least 3-4 mm depth of the
pulp chamber or a minimum of 1 mm
cervico-occlusal dimension above the
gingival margin is required, and such
complex fabrication may not always be
feasible. In the case of inadequate tooth
structure to ensure sufficient retention,
it is advisable to do a core build-up via
direct techniques first and then prepare
the tooth to receive complete coverage via
indirect composite restoration.
Among all the parameters recorded
while evaluating parental satisfaction, the
lowest parental satisfaction scores were
reported for the cost of the restorations.
The cost of an indirect composite onlay
is approximately US $8.30 in the clinic
used in this study, while the approximate
cost for an SSC is approximately US
$5.80. Furthermore, patients visiting the
clinic used in this study are from mixed
socioeconomic backgrounds. The authors
did not analyze the relationship of the
parents’ socioeconomic background (such
as ability to pay) with the satisfaction
with the cost of indirect restorations. The
lower satisfaction regarding cost might
be due to the slightly higher cost of indirect composite restorations and/or poor
socioeconomic status. These findings suggest that indirect composite restorations
should be the treatment of choice only
when the patient and/or his/her parents’
priority is excellent esthetics over cost.
Even though an extra visit is required for
placing indirect composite onlays, the
overall chairside time is not much different since the dentist can place multiple
onlays in a single visit.
This study is the first report on the clinical outcomes of indirect composite onlays
in a pediatric population. The limitations
of this study include a small convenience
sample and the absence of any comparison
group. Further randomized, controlled
trials with comparative evaluations and
established modalities—such as preformed
SSCs, veneered SSCs, and direct composite restorations—are needed.
Conclusion
Indirect composite onlays not only
satisfactorily restored function but also
resulted in excellent esthetics for the
patients in this study. However, the limitations of a slightly longer chairside time
and a slightly higher cost must be kept
in mind. More randomized, controlled
trials to generate evidence to compare
this technique to traditional treatment
modalities are needed.
Author information
Dr. Mittal is an assistant professor,
Department of Pediatric and Preventive
Dentistry, Santosh Dental College and
Hospital, Ghaziabad, India, where
Dr. Srivastava is a professor and department head.
References
1. Marthaler TM. Changes in dental caries 1953-2003.
Caries Res. 2004;38(3):173-181.
2. Fishman R, Guelmann M, Bimstein E. Children’s selection of posterior restorative materials. J Clin Pediatr
Dent. 2006;31(1):1-4.
3. Ram D, Peretz B. Composite crown-form crowns for
severely decayed primary molars: a technique for restoring function and esthetics. J Clin Pediatr Dent.
2000; 24(4):257-260.
4. Mortada A, King NM. A simplified technique for the
restoration of severely mutilated primary anterior
teeth. J Clin Pediatr Dent. 2004; 28(3):187-192.
5. Yilmaz Y, Kocogullari ME. Clinical evaluation of two
different methods of stainless steel esthetic crowns.
J Dent Child (Chic). 2004;71(3):212-214.
6. Leith R, O’Connell AC. A clinical study evaluating success of 2 commercially available preveneered primary
molar stainless steel crowns. Pediatr Dent. 2011;33(4):
300-306.
7. Shortall AC, Baylis RL, Baylis MA, Grundy JR. Marginal
seal comparisons between resin-bonded Class II porcelain inlays, posterior composite restorations, and direct composite resin inlays. Int J Prosthodont. 1989;
2(3):217-221.
8. Yap AU, Ong LF, Teoh SH, Hastings GW. Comparative wear ranking of dental restoratives with the
BIOMAT wear simulator. J Oral Rehabil. 1999;26(3):
228-235.
9. Burke FJ, Watts DC, Wilson NH, Wilson MA. Current
status and rationale for composite inlays and onlays.
Br Dent J. 1991;170(7): 269-273.
10. Villalta P, Oliveira LB, Imparato JC, Rodrigues CR. Indirect composite onlay restorations in primary molars: a
clinical report. J Clin Pediatr Dent. 2006; 31(1):17-20.
11. el-Mowafy O. Management of extensive carious lesions in permanent molars of a child with nonmetallic
bonded restorations—a case report. J Can Dent Assoc.
2000;66(6):302-307.
12. Ryge G. Clinical criteria. Int Dent J. 1980;30(4):347358.
13. Roberts C, Lee JY, Wright JT. Clinical evaluation of and
parental satisfaction with resin-faced stainless steel
crowns. Pediatr Dent. 2001;23(1):28-31.
14. Wong DL, Baker CM. Pain in children: comparison of
assessment scales. Pediatr Nurs. 1988;14(1):9-17.
15. Mata AF, Bebermeyer RD. Stainless steel crowns versus
amalgams in the primary dentition and decision-making in clinical practice. Gen Dent. 2006;54(5):347350; quiz 351, 367-368.
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16. Attari N, Roberts JF. Restoration of primary teeth with
crowns: a systematic review of the literature. Eur Arch
Paediatr Dent. 2006;7(2):58-62; discussion 63.
17. Zimmerman JA, Feigal RJ, Till MJ, Hodges JS. Parental
attitudes on restorative materials as factors influencing current use in pediatric dentistry. Pediatr Dent.
2009;31(1):63-70.
18. Ram D, Fuks AB, Eidelman E. Long-term clinical performance of esthetic primary molar crowns. Pediatr Dent.
2003;25(6):582-584.
19. Eick JD, Welch FH. Polymerization shrinkage of posterior composite resins and its possible influence on
postoperative sensitivity. Quintessence Int. 1993;
17(2):103-111.
Manufacturers
DENTSPLY International, York, PA
800.877.0020, www.dentsply.com
GC America, Inc., Alsip, IL
800.323.7063, www.gcamerica.com
Ivoclar Vivadent, Inc., Amherst, NY
800.533.6825, www.ivoclarvivadent.us
Microsoft, Redmond, WA
425.882.8080, www.microsoft.com
Shofu Dental Corporation, San Marcos, CA
800.827.4638, www.shofu.com
Sirona Dental Systems, Inc., Charlotte, NC
800.659.5977, www.sironausa.com
SPSS, Inc., Quarry Bay, Hong Kong
852.2811.9662, www.spss.com
Unicorn DenMart, New Dehli, India
011.45551200, www.unicorndenmart.com
3M ESPE, St. Paul, MN
888.364.3577, solutions.3m.com
General Dentistry
May/June 2015
e21
Diagnosis of Oral Pathology
Clinicopathological aspects of 25 cases of
sialolithiasis of minor salivary glands
Marco Tullio Brazao-Silva, DDS, PhD n Fabio Cesar Prosdocimi, DDS, PhD n Celso Augusto Lemos-Junior, DDS, PhD Suzana Cantanhede Orsini Machado de Sousa, DDS, PhD
metaplasia of the affected duct. Ectasia, squamous and mucous metaplasia, mucous plug formation, and cellular debris were seen in adjacent
ducts. Clinicians should be aware of SMSG, especially with regard to its
higher incidence in the upper lip and buccal mucosa.
Received: April 22, 2014
Accepted: August 21, 2014
Sialolithiasis of minor salivary glands (SMSG) is rarely reported and
presumably represents an underestimated disease. This study examined
the clinicopathological aspects of 25 selected SMSG cases over an
11-year period at the Oral Pathology Department of the University of
Sao Paulo, Brazil. SMSG was not a clinical diagnosis in 92% of the cases.
Histologically, the sialoliths tended to be superficial and formed by concentric layers with variable degrees of mineralization. Chronic periductal
and parenchymal inflammation were frequent, as well as squamous
S
Key words: sialolithiasis, salivary glands, minor, diagnosis, histopathology
of SMSG cases due to cases that are missed
either clinically, as some lesions may resolve
spontaneously, or histologically, as a sialolith may not appear in histopathological
sections. Therefore, a retrospective study on
these lesions can be helpful for clinicians
and pathologists to improve their recognition of SMSG. The present study aimed to
describe the clinical and histopathological
aspects of SMSG cases diagnosed during a
period of 11 years.
ialolithiasis is the most common form
of obstructive sialadenitis.1 It is caused
by the formation of a sialolith, a rigid
structure generally consisting of a mixture
of different calcium phosphates and an
organic matrix.1 Sialolithiasis is one of the
most common salivary gland diseases and
is often attributed to the submandibular
gland. The involvement of minor glands
is rarely reported (<1%), and only a few
studies have described the clinicopathological characteristics of sialolithiasis of minor
salivary glands (SMSG) in the differential
diagnosis of mucosal lesions.2-5 This omission has likely led to an underestimation
Materials and methods
Histopathology records from 2000-2011
were obtained from the Department of
Chart 1. Primary clinical diagnoses
for the 25 cases in this study.*
Chart 2. Secondary clinical diagnoses
for the 25 cases in this study.
4
4
Buccal mucosa
Palate
Buccal mucosa
Lower lip
Upper lip
Tongue
Upper lip
Palate
General Dentistry
is
as
hi
li t
Sia
lo
no
m
a
is
os
de
ta
la d
en
fS
Sia
so
Abbreviation: SG, salivary gland.
Cy
s
a
m
or
Fi b
ele
oc
uc
ro
Tu
m
Sia
la d
en
as
hi
li t
lo
Sia
ou
ce
ba
Se
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it i
is
t
ys
r
sc
ce
a
ul
m
Ap
ht
ho
us
de
om
Le
uk
oe
G
gi
fS
an
He
m
to
om
Cy
s
G
so
or
L ip
fS
m
ro
Tu
m
Fi b
oc
it i
uc
M
en
la d
Sia
*Two clinicians did not provide any hypothesis of clinical diagnosis. Abbreviation: SG, salivary gland.
May/June 2015
s
0
a
0
a
1
a
1
ele
2
s
2
G
3
Lower lip
M
3
e22
Oral Pathology of the University of Sao
Paulo, Brazil, and all diagnoses containing
the term sialolithiasis were reviewed. In
addition, cases of salivary gland pathology with a descriptive diagnosis of ductal
ectasia and/or sialadenitis were reviewed,
since these conditions often result from
the presence of a calculus, and an existing
sialolith may have been missed due to an
insufficient number of histological sections
included in the original analysis.
In this study, a diagnosis of sialolithiasis
was only confirmed if a sialolith was present. A sialolith was interpreted as a mineralized tissue lined by ductal epithelial cells
Table. Clinical and histological summary of sialolithiasis of minor salivary glands.
Sialoliths
Gender
Age
(yr)
Anatomical location (depth)
1
Male
71
2
Female
3
Female
4
Male
NA
5
Male
36
6
Male
58
7
Female
65
8
Male
70
Case
Number
Morphology
Color
Duct
Gland parenchyma2
Buccal mucosa (S)
Single
Laminated
Homogeneous
Squamous metaplasia
Inflamed (L)
57
Tongue (S)
Multiple
Laminated
Homogeneous
Atrophic
Inflamed (M)/atrophic
69
Buccal mucosa (S)
Single
Laminated
Heterogeneous
Squamous metaplasia
Inflamed (L)
Upper lip (S)
Single
Laminated
Heterogeneous
Mucous metaplasia/
abscedation
Inflamed (S)/atrophic
Upper lip (D)
Single
Continuous
Homogeneous
Atrophic
Inflamed (S)/atrophic
Upper lip (D)
Multiple
Laminated
Homogeneous
Squamous metaplasia
Inflamed (M)/atrophic
Upper lip (S)
Single
Laminated
Homogeneous
Squamous metaplasia
Inflamed (S)/atrophic
Upper lip (S)
Single
Laminated
Homogeneous
Atrophic
Normal
1
9
Male
77
Lower lip (S)
Single
Laminated
Heterogeneous
Atrophic/abscedation
Inflamed (M)/atrophic
10
Female
61
Upper lip (S)
Single
Mixed
Homogeneous
Squamous metaplasia
Normal
11
Female
72
Lower lip (D)
Single
Continuous
Heterogeneous
Squamous metaplasia
Inflamed (M)/atrophic
12
Male
67
Buccal mucosa (D)
Multiple
Laminated
Homogeneous
Atrophic
Inflamed (S)/atrophic
13
Male
62
Upper lip (S)
Single
Mixed
Heterogeneous
Squamous metaplasia
Inflamed (L)
14
Male
74
Upper lip (S)
Single
Laminated
Heterogeneous
Squamous metaplasia
Inflamed (L)
15
Male
67
Upper lip (D)
Single
Continuous
Heterogeneous
Squamous metaplasia
Normal
16
Female
63
Buccal mucosa (D)
Single
Continuous
Heterogeneous
Squamous metaplasia
Inflamed (L)/atrophic
17
Female
41
Buccal mucosa (S)
Single
Continuous
Homogeneous
Atrophic
Normal
18
Female
28
Upper lip (S)
Single
Laminated
Homogeneous
Squamous metaplasia
Normal
19
Male
76
Buccal mucosa (S)
Single
Laminated
Heterogeneous
Squamous metaplasia
Inflamed (L)
20
Female
57
Buccal mucosa (D)
Single
Laminated
Homogeneous
Atrophic/abscedation
Inflamed (L)/atrophic
21
Female
59
Palate (D)
Multiple
Laminated
Homogeneous
Squamous metaplasia
Atrophic
22
Female
35
Buccal mucosa (S)
Single
Laminated
Homogeneous
Squamous metaplasia
Atrophic
23
Male
65
Buccal mucosa (S)
Multiple
Laminated
Homogeneous
Atrophic
Inflamed (M)/atrophic
24
Male
53
Upper lip (S)
Single
Laminated
Heterogeneous
Mucous metaplasia
Normal
25
Male
26
Floor of mouth (D)
Multiple
Mixed
Heterogeneous
Squamous metaplasia
Inflamed (S)/atrophic
Depth of sialolith: D, deep; S, superficial. 2Level of inflammation: L, low; M, moderate; S, severe. Abbreviation:NA, not available.
1
or within the salivary gland parenchyma.
In addition, an SMSG diagnosis was only
considered when the sialolith was found
within a minor salivary gland. Data such
as age, gender, site of lesion, and clinical
diagnosis, as well as histopathological
characteristics—such as gland parenchyma alterations (atrophy, edema, and
inflammation), duct alterations (metaplasia, ectasia, and adjacent inflammatory
infiltrate), and aspects of the sialolith
(structural arrangement, staining pattern,
localization in the tissue, and number of
calculi)—were analyzed. Descriptive statistics were used when appropriate.
Results
Within the 11 year period, 25 cases of
SMSG were reviewed, constituting 0.06%
of all oral pathologies diagnosed in this
period. Of the SMSG patients, 14 were
males (56%), and the male to female ratio
was 1.3:1. Patients’ ages ranged from 26 to
77 years, with a mean age of 58.7 (±14.9)
years. Peak age of onset was in the seventh
(8 cases) and eighth (6 cases) decades of
life, occurring in 56% of cases. Almost
all lesions were clinically misdiagnosed
(92%). The suspicion of a salivary gland
tumor was most common (24%), followed by fibroma (20%) and nonspecific
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sialadenitis (20%). When misdiagnosed, the
incorrect choice of clinical diagnosis seemed
to be site-specific (Chart 1). Clinicians
tended to call the lesions sialadenitis,
mucocele, or lipoma when they involved
the buccal mucosa and fibroma or tumor of
the salivary gland when they involved the
upper lip. SMSG was suggested as a secondary clinical diagnosis in 2 cases (8%), one
in the upper lip and the other in the buccal
mucosa (Chart 2). Two clinicians did not
provide any hypothesis of clinical diagnosis.
Histopathological analyses showed that
24% of the sialoliths occurred in multiples, while the rest were single. Sixty-four
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Diagnosis of Oral Pathology Clinicopathological aspects of 25 cases of sialolithiasis of minor salivary glands
percent were located superficially on the
mucosa; the rest were located at deeper
locations. The sialoliths were mostly
composed of laminated concentric layers
(68%), but some were formed by a continuous calcified mass showing a globular
calcification pattern (20%). The staining
characteristics varied from homogeneous
(56%) to heterogeneous (44%); these
were of a predominantly basophilic pattern. Direct contact between the sialolith
and adjacent ductal epithelium revealed
squamous metaplasia in 60% of the
cases. Twenty-eight percent of the ducts
were atrophic; mucous metaplasia was
rare (8%). Periductal inflammation was
present in 72% of the cases, and 48% of
these cases were chronic. Abscess formation and granulation tissue surrounding
the sialolith were observed in 16% of the
cases. Parenchymal alterations included
atrophy (48%) and chronic sialadenitis
(68%), with 28% of the cases exhibiting
moderate chronic sialadenitis. Ductal
ectasia and mucous/squamous metaplasia
were each found in 12% of the cases;
exfoliated ductal epithelial cells were seen
in the parenchyma or adjacent ducts in
8% of the cases (Table). Figures 1-3 depict
illustrative cases of SMSG.
Discussion
The present study explored the clinical and
histological aspects of SMSG diagnosed
during a period of 11 years, and the small
number of cases reported indicates that it
is a rarely diagnosed disease. Previous studies have shown that SMSG is rarely considered among clinical diagnoses.3,4 In the
present study, fibroma, mucocele, tumor
of the salivary gland, and nonspecific sialadenitis were the most frequent presumptive diagnoses. It is interesting to note that
even though mucoceles are uncommon
in the upper lip and buccal mucosa, they
were among the most common clinical
diagnoses.6 Epidemiologically, more
appropriate diagnoses would be fibroma,
salivary gland tumors, and lipoma, considering their higher frequencies, similar
clinical aspects, and common sites of
involvement.7-10 The clinical diagnosis of
SGSM was regarded in 2 cases as a secondary diagnosis.
SMSG has been characterized in the
literature as a disease with no relation
to age, gender, or site of involvement.11
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May/June 2015
General Dentistry
Fig. 1. Left. Clinical view of a well-circumscribed swelling in the right upper lip of a 65-year-old man who
reported a painless lesion present for 1 month. Right. Histopathological cross-section of the same swelling
showing a single heterogeneous sialolith in an excretory duct presenting squamous metaplasia, surrounded
by chronic inflammation (magnification 100X). Sialoliths (arrow) are associated with minor glands (*).
Fig. 2. Left. Clinical view of a superficial and mobile lesion affecting the buccal mucosa in a 72-year-old
woman. The lesion was asymptomatic and present for 3 months. Right. Histopathological cross-section of
the same lesion showing a single, homogeneous sialolith formed by globular calcifications, limited in a duct
with squamous metaplasia and surrounded by mild inflammation (magnification 100X). Sialoliths (arrow) are
associated with minor glands (*).
However, we observed 2 peaks of incidence, both involving the elderly. Mean
age of onset was 58.7 years. This finding
has been corroborated in other studies that showed a higher prevalence of
SMSG in patients over 45 years of age.2-5
This characteristic could indicate that
the metaplastic changes of ductal cells
and saliva due to aging may contribute
to sialolith formation.12 However, the
specific etiology of this disease is still
unclear and may be multifactorial. A
male predisposition was found in other
studies, but the differences between
the genders was not significant.3-5 With
respect to the site of involvement, the
data from this study support the conclusion that the upper lip is most susceptible
to SMSG, as more than 40% of the
cases occurred there. This finding is in
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accordance with a review that showed
that upper lip lesions account for 49.2%
of SMSG cases.5
In view of the clinical aspects observed
for SMSG, it can be defined as a submucosal and well-delimited palpable
mass, mostly involving adults and eldery
patients and the upper lip/buccal mucosa.
An awareness of the features of this entity
may aid in the differential diagnoses of
submucosal masses. Additionally, periapical radiographs may have some value in
the diagnosis of those cases with wellmineralized sialoliths.4
In this study, the majority of the
sialoliths were homogeneously stained,
presenting concentric onion-like calcifications. However, there were some cases
of sialoliths with heterogeneous staining
characteristics presenting multifocal
intramucosal nodules (mainly in adults
over 45 years of age) and nonspecific localized sialadenitis.2-4,18,19 SMSG has been
adequately treated by surgical excision of
the mass containing the sialolith and the
involved gland under local anesthesia.2-4
Spontaneous resolution in some cases is
possible. Recurrence is not common and
may indicate the presence of multiple,
previously undiagnosed sialoliths.3
Fig. 3. Left. A painless erythematous lesion (1-month duration) on the hard palate of a 59-year-old woman.
Right. Histopathological cross-section of the same lesion showing multiple concentric heterogeneous
sialoliths in metaplastic ducts; the gland parenchyma was substituted by intense chronic inflammation
(magnification 100X). Sialoliths (arrows) are associated with minor glands.
internal globular calcifications. In addition, a majority of the cases presented
multiple sialoliths, clearly indicating
the existence of a distinct pathogenesis
among cases, as well as the possibility
of multiple areas of sialolithogenesis.
Sialoliths consist of mixtures of different calcium phosphates in an organic
matrix that appear to be required to
trigger embedding within a duct.1 A variable spectrum of sialoliths was observed
in this study, and they may represent
distinct sources of organic material,
including exfoliated ductal epithelial
cells, bacterial colonies, foreign bodies,
and mucous plugs.1,13-15 However, alterations of salivary composition—such as
in viscosity or salt concentration—have
also been presented as possible factors.1
Furthermore, isolated cases of sialolithiasis have been described in patients
presenting primary hyperparathyroidism,
gout, and kidney transplantation.16,17
Currently, the findings of this and other
studies indicate that SMSG is a multifactorial, nonspecific disease, and at present
there is no study with a relatively large
number of patients that indicates specific
systemic predisposing factors.
Two of the retrieved cases in this study
were previously diagnosed as ductal
ectasia; these diagnoses were changed to
SMSG during the reviewing process when
sialoliths were found after additional histopathological sections were obtained and
analyzed. Thus, to avoid laboratory misdiagnoses, it is important to emphasize
the histopathological findings recorded in
this study, such as squamous metaplasia of
involved ducts (>50%, sometimes including adjacent ducts), mucous metaplasia
(<50%), and inflammation of the gland
parenchyma (68%). This suggests that
SMSG should be suspected by clinicians
facing a histological picture of a sialadenitis without apparent cause.
Acinar atrophy, ductal ectasia (sometimes with deep cystic dilatation), and
periductal inflammation were also found
in this study; these are frequent components of SMSG histopathology. All of
these findings must also be considered in
distinguishing cases with mucous metaplasia from low-grade mucoepidermoid
carcinomas or cases with cystic dilatation
from cystadenomas. Furthermore, even
in the presence of a calcification, other
alterations such as phleboliths and dystrophic calcification (such as that caused
by trauma) must be considered. Hence,
alterations in the adjacent minor salivary
glands and the presence of a surrounding
duct epithelium in the histopathological sections are very important factors
to be considered in a diagnosis. When
the ductal epithelium is disrupted by a
sialolith, microabscess formation and the
development of granulation tissue can be
observed. These cases may mimic mucoceles, as observed in a 2011 case report.18
Finally, this study is in agreement
with others that showed SMSG is an
underestimated disease, occurring more
frequently than previously assumed, and
should be included in the clinical and
histopathological differential diagnoses of
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Conclusion
Clinicians should be aware of the incidence
of SMSG, especially with regard to its
higher incidence in the upper lip and
buccal mucosa, involving adults and the
elderly. This study reported important elements to consider when identifying SMSG.
The present data expand the knowledge
about the spectrum of the disease.
Author information
Dr. Brazao-Silva is a professor and chair
of the School of Dentistry, School of
Health Sciences, University of the State of
Amazonas, Manaus, Brazil. Drs. BrazaoSilva and Prosdocimi are postdoctoral candidates in the Departments of Stomatology
and Basic and Applied Pathology, School
of Dentistry, University of Sao Paulo,
Brazil, where Dr. Lemos-Junior is a professor and chair of the Department of
Stomatology, and Dr. de Sousa is a professor and chair of the Department of Oral
Pathology, CNPq granted.
References
1. Grases F, Santiago C, Simonet BM, Costa-Bauza A. Sialolithiasis: mechanism of calculi formation and etiologic factors. Clin Chim Acta. 2003;334(1-2):131-136.
2. Jensen JL, Howell FV, Rick GM, Correll RW. Minor salivary gland calculi. A clinicopathologic study of fortyseven new cases. Oral Surg. 1979;47(1):44-50.
3. Anneroth G, Hansen LS. Minor salivary gland calculi. A
clinical and histopathological study of 49 cases. Int J
Oral Surg. 1983;12(2):80-89.
4. Alcure ML, Della Coletta R, Graner E, Di Hipolito O Jr,
Lopes MA. Sialolithiasis of minor salivary glands: a
clinical and histopathological study. Gen Dent. 2005;
53(4):278-281.
5. Ben Lagha N, Alantar A, Samson J, Chapireau D, Maman L. Lithiasis of minor salivary glands: current data.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod.
2005;100(3):345-348.
6. Chi AC, Lambert PR 3rd, Richardson MS, Neville BW.
Oral mucoceles: a clinicopathologic review of 1,824
cases, including unusual variants. J Oral Maxillofac
Surg. 2011;69(4):1086-1093.
7. Al-Khateeb TH. Benign oral masses in a Northern Jordanian population-a retrospective study. Open Dent J.
2009;3:147-153.
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May/June 2015
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Diagnosis of Oral Pathology Clinicopathological aspects of 25 cases of sialolithiasis of minor salivary glands
8. Manor E, Sion-Vardy N, Joshua BZ, Bodner L. Oral lipoma: analysis of 58 new cases and review of the literature. Ann Diagn Pathol. 2011;15(4):257-261.
9. Caldeira PC, de Sousa SF, Johann AC, et al. A submucosal tumor of the upper lip. Oral Surg Oral Med Oral
Pathol Oral Radiol Endod. 2009;108(5):656-660.
10. Ntomouchtsis A, Karakinaris G, Poulolpoulos A, et al.
Benign lip lesions. A 10-year retrospective study. Oral
Maxillofac Surg. 2010;14(2):115-118.
11. Gregori G, Pippen W. Sialolithiasis with sialoadenitis of
a minor salivary gland. Oral Surg. 1970;30(3):320-324.
12. Holst E. The clinical entity of sialolithiasis of the
minor salivary glands. Acta Odontol Scand. 1971;
29(1):75-84.
13. Yamane GM, Scharlock SE, Jain R, SunderRaj M,
Chaudhry AP. Intraoral minor salivary gland sialolithiasis. J Oral Med. 1984;39(2):85-90.
14. Mimura M, Tanaka N, Ichinose S, Kimijima Y, Amagasa
T. Possible etiology of calculi formation in salivary
glands: biophysical analysis of calculus. Med Mol Morphol. 2005;38(3):189-195.
15. Lee LT, Wong YK. Pathogenesis and diverse histologic
findings of sialolithiasis in minor salivary glands. J Oral
Maxillofac Surg. 2012;68(2):465-470.
16. Stack BC Jr, Norman JG. Sialolithiasis and primary hyperparathyroidism. ORL J Otorhinolaryngol Relat Spec.
2008;70(5):331-334.
17. Soares LP, Gaiao de Melo L, Pozza DH, Pinheiro AL,
Gerhardt de Oliveira M. Submandibular gland sialolith
in a renal transplant recipient: a case report. J Contemp Dent Pract. 2005;6(3):127-133.
18. Okada H, Yokokawa M, Komiya M, Akimoto Y, Kaneda
T, Yamamoto H. A rare case of sialolithiasis of the lower lip simulating a mucocele and review of the literature. Quintessence Int. 2011;42(7):589-594.
19. Hurlen B, Kopang HS. Sialolithiasis in minor salivary
glands. Case report [in Norwegian]. Nor Tannlaegeforen Tid. 1976;86(4-1):148-153.
e26
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General Dentistry
www.agd.org
Medical Health History/Factors
Oral manifestations in gastroesophageal
reflux disease
Preetha A., MDS n Sujatha D., MDS n Bharathi A. Patil, MDS n Sushmini Hegde, MDS
Many systemic diseases exert their influence on oral health. Among
these, gastroesophageal reflux disease (GERD) is the most common. In
this study, 100 patients who were previously diagnosed with GERD were
examined following a 12-hour fast and evaluated in terms of the severity
(grade) of the disease as well as any oral, dental, and/or salivary pH
changes. Results found 11 patients with tooth erosion. These patients
were older, and their average mean duration of GERD was longer in
comparison to those without erosion. There was an inverse relationship between salivary pH and the GERD duration and grade of severity.
As the GERD grade increased, the severity of tooth erosion increased.
G
astroesophageal reflux disease
(GERD) is a common medical
condition that affects 35%-40% of
the adult population.1 GERD is characterized by the regurgitation of gastric and
duodenal contents into the esophagus
and oral cavity.2 The regurgitated acidic
liquid usually contains pepsin, a digestive
enzyme produced by stomach bile that
has backed up into the stomach from
the duodenum.3 Pepsin is most active in
acidic environments and is believed to be
the most injurious component of refluxed
liquid, responsible for the oral and dental
manifestations associated with GERD.1
Normally when acid enters the mouth
from intrinsic or extrinsic sources, saliva
washes the acid away. This results in an
increase in the salivary flow rate and
Patients with erosion also exhibited oral mucosal changes. Thus severe,
long-term GERD was found to be potentially detrimental to oral soft
tissues, dental structures, and salivary pH, whereas milder forms of the
disease did not necessarily cause dental side effects.
Received: August 27, 2013
Revised: October 9, 2013
Accepted: November 12, 2013
Key words: GERD, acid reflux, salivary pH, oral manifestations,
xerostomia, taste change, burning mouth sensation, tooth erosion
buffering capacity. The buffering capacity
regulates the salivary pH. In an ideal oral
environment, when an acid is introduced
into the oral cavity, the acid is neutralized within minutes and the salivary pH
returns to normal.4
The aim of this study was to evaluate
the oral and dental manifestations of
GERD, and to correlate these manifestations with salivary pH changes in patients
with this disease.
Materials and methods
The study consisted of patients (n = 100)
who were endoscopically diagnosed as
having GERD by a gastroenterologist
in the Department of Gastroenterology,
Bangalore and Bhagwan Mahaveer Jain
Hospitals, India.
Patients included in this study had at
least 20 teeth in the mouth (including
the maxillary anteriors from tooth No. 5
to tooth No. 12) and were diagnosed as
having GERD by the gastroenterologist. All
patients were required to sign an informed
consent. Patients excluded from this study
were those that were pregnant, edentulous,
and/or on the following medications: anticholinergics, antidepressants, antipsychotics, antihypertensives, or antacids.
The 100 patients fasted for 12 hours,
at which point each was examined under
bright illumination using a mouth mirror
and probe.
Salivary pH assessment
Unstimulated whole salivary pH was
recorded. Salivary pH was recorded using
Table 1. Number (percentage) of oral manifestations according to duration of gastroesophageal reflux
disease (GERD) in the study.
Duration of
GERD (years)
Patients
(n)
Dry
mouth
Taste
change
Burning mouth
sensation
Mouth
sores
Tooth
erosion
Tooth
sensitivity
Myofascial
pain
<1
64
1 (1.6)
0
0
0
1 (1.6)
0
0
1-3
32
4 (12.5)
0
4 (12.5)
4 (12.5)
7 (21.9)
6 (18.8)
0
3-5
2
2 (100.0)
1 (50.0)
2 (100.0)
0
2 (100.0)
2 (100.0)
0
>5
2
2 (100.0)
1 (50.0)
1 (50.0)
1 (50.0)
1 (50.0)
1 (50.0)
0
100
9 (9.0)
2 (2.0)
7 (7.0)
5 (5.0)
11 (11.0)
9 (9.0)
0
-
<0.001
0.001
<0.001
<0.001
<0.001
<0.001
-
Total
P value
Note: All P values in the table are considered to be strongly significant ( P ≤ 0.01).
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Medical Health History/Factors Oral manifestations in gastroesophageal reflux disease
Table 2. Correlation between GERD and tooth erosion
grades in the study.
Number of patients with
tooth erosion (n = 11)
Table 3. Correlation between GERD grade and salivary pH
in the study.
Grades of tooth erosion
Grade I
Grade II
pH
Grade III
GERD Grade A (n = 2)
2
0
0
GERD
GERD Grade B (n = 4)
4
0
0
Grade A
6.5-7.5
7.17 (0.28)
0
Grade B
6.5-7.5
6.93 (0.26)
Grade C
6.0-7.0
6.58 (0.38)
GERD Grade C (n = 5)
0
5
Definitions: GERD Grade A, exhibits 1 (or more) mucosal breaks ≤5 mm and
does not extend between the tops of 2 mucosal folds; GERD Grade B, exhibits
1 (or more) mucosal breaks >5 mm long and does not extend between the tops
of 2 mucosal folds; GERD Grade C, exhibits 1 (or more) mucosal breaks which are
continuous between the tops of 2 or more mucosal folds but involves less than
75% of the circumference.
pH measuring strips (Universal strips,
GlaxoSmithKline). Each patient was asked
to pool saliva on the tongue and a pH strip
was placed to wet it. The color change was
immediately matched directly with the
scale provided with the strip, and the pH
was recorded.
Oral manifestations
Specific oral manifestations were classified
into subjective and objective findings.
Subjective findings included dry mouth,
changes in taste, burning mouth and
pharynx sensations, and nonspecific itching. To assess the subjective findings, each
patient was asked questions regarding the
symptoms; their responses were recorded
as present or absent. Dry mouth was selfrecorded using a questionnaire.
Objective findings included oral ulcerations, dental erosion, dentinal hypersensitivity, temporomandibular disorder (TMD),
and myofascial pain. Dental erosion was
recorded as follows: Grade I, erosion lesion
restricted to enamel; Grade II, erosion
lesion involves dentin, but for <1/3 of the
tooth surface; Grade III, erosion involves
dentin for >1/3 of the tooth surface.
Statistical analysis
Descriptive statistical analyses were
conducted in this study. Significance was
assessed at 5%. Chi-square and Fisher
exact tests were used to find the significance of study parameters on a categorical
scale between 2 or more groups. A 95%
confidence interval was computed to
find the significant features. Results were
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May/June 2015
General Dentistry
Minimum-maximum
Mean (standard deviation)
Definitions: Grade A, exhibits 1 (or more) mucosal breaks ≤5 mm and does not extend
between the tops of 2 mucosal folds; Grade B, exhibits 1 (or more) mucosal breaks
>5 mm long and does not extend between the tops of 2 mucosal folds; Grade C, exhibits
1 (or more) mucosal breaks which are continuous between the tops of 2 or more mucosal
folds but involves less than 75% of the circumference.
Table 4: Correlation between tooth erosion grade and mean salivary pH in the study.
Tooth
erosion
pH
Minimum-maximum
Mean (standard deviation)
Grade I
6.8-7.5
7.01 (0.25)
Grade II
6.0-7.0
6.50 (0.35)
Definitions: Grade I, erosion lesion restricted to enamel; Grade II, erosion lesion involves dentin,
but for <1/3 of the tooth surface.
deemed suggestive, moderately, or strongly
significant based on P values of 0.05
< P < 0.10, 0.01 < P ≤ 0.05, and P ≤ 0.01,
respectively. Statistical software (SPSS
15.0, SPSS, Inc.; Stata 8.0, StataCorp LP;
MedCalc 9.0.1, MedCalc Software bvba;
and Systat 11.0, Systat Software, Inc.) was
used for the analysis of the data.5-7
Results
This study found that severe GERD of
long duration was detrimental to teeth,
whereas milder forms of the disease did
not cause dental side effects (Table 1).8
GERD Grade A exhibits 1 (or more)
mucosal breaks ≤5 mm and does not
extend between the tops of 2 mucosal
folds. GERD Grade B exhibits 1 (or
more) mucosal breaks >5 mm long and
does not extend between the tops of 2
mucosal folds. GERD Grade C exhibits
1 (or more) mucosal breaks which are
continuous between the tops of 2 or more
mucosal folds but involves less than 75%
of the circumference.
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Nine percent of the patients in this
study had dry mouth. The results
indicated that as the GERD grade
increased, the prevalence of dry mouth
also increased. The percentage of patients
exhibiting tooth sensitivity when subjected to thermal stimuli was also 9%.
Both of these findings were statistically
significant (P < 0.001). Two percent of
the patients had changes in taste, and
this was also deemed clinically significant
(P = 0.003). Seven percent of the patients
had burning mouth sensations, and 11%
had tooth erosion (Table 2); both values
were deemed statistically significant
(P < 0.001).
The results of this study showed that
tooth erosion was prevalent at 6.5 salivary
pH (Table 3). It was found that as the
GERD grade increased, the severity of
tooth erosion increased; however, the salivary pH decreased (Table 4).
Mouth sores in the present study were
recorded based on each patient’s clinical
history, and the prevalence was deemed
to be statistically significant (P < 0.001).
None of the patients in this study presented
symptoms of TMD or myofascial pain.
Discussion
The mean age of patients in this study
was 46.28 years for men and 44.75 years
for women. The majority of patients
were between 31 and 50 years of age. The
majority of patients were male (64%). This
was in accordance with previous studies
by Kasper et al and Meurman et al, which
showed male prevalences of 64.5% and
75.4%, respectively.3,8
Acid regurgitation and dysphagia
Typical symptoms of GERD are heartburn
(72%), acid regurgitation (44%), and dysphagia (36%).9 However, a high percentage
of patients with extraesophageal manifestations of GERD—such as laryngitis; chronic
cough; chest pain; and ear, nose, and throat
problems—do not display the typical
symptoms.10-12 This could retard both the
diagnosis and treatment of GERD. In the
present study, 10% of the study population had dysphagia and 56% had gastric
regurgitation as their presenting symptoms.
However, a study by Moshkowitz et al
reported 100% of the study subjects presenting with gastric regurgitation.13
Oral manifestations
The effects of chronic exposure of the oral
cavity to gastric acid can be profound, and
may include mucosal ulceration/erosion,
loss of taste, soft/hard palate erythema,
oral ulcers, xerostomia, dental erosion,
dentinal hypersensitivity, severe tooth
destruction (leading to loss of occlusion),
TMD, and myofascial pain.1,9,10,14
Most previous GERD studies have
focused solely on the effects of the disease
on the teeth. While soft tissue symptoms
have been mentioned in the literature,
pathognomic soft tissue lesions have not
been extensively documented.15
Dry mouth
The incidence of dry mouth in GERD
patients has been previously studied, and
the prevalence in these studies was statistically significant, in accordance with the
present study.7,16 One study of a GERD
patient population (n = 200) reported a
54.5% incidence of dry mouth, which
was statistically significant (P = 0.0001).7
Campisi et al found in their study of 120
GERD patients that a statistically significant percentage of their patients (57.5)
experienced dry mouth (P < 0.0001).16
The subjective feeling of mouth dryness
is directly related to saliva.12 Saliva acts by
directly neutralizing the acids in the oral
cavity. A sensation of dry mouth might be
indicative of a deficit in salivary secretion,
with a resultant reduced salivation and
subsequent insufficient clearance, dilution,
and buffering of gastric acids.16
Upper gastrointestinal mucosal irritation
has long been thought to stimulate salivation. Salivary hypofunction in patients
with GERD is due to the inability to
reach adequate stimulated performances,
which suggests that there is a defect in
the esophageal salivary reflux.17 An insufficient salivary flow has been associated
with low clearance and a reduced capacity
for esophageal acid neutralization; hence
GERD could be considered as a primary
etiopathogenic factor in salivary dysfunction.17 However, no definitive conclusions
have been established with regard to the
potential reactive or modulating relationship between the physiological mechanism
of salivary hypofunction and GERD.18-20
According to the literature, drugs
such as anticholinergics, antidepressants,
antipsychotics, antihypertensives, antidiabetics, antihistamines, and antacids are
all associated with decreased salivary secretion, thereby causing dry mouth. In the
present study, any patients who were on
these types of medications were excluded
from the study. Hence, the dry mouth
incidence in the present study was not
related to these drugs or their side effects.
Taste change
Very few studies have recorded the sensation of taste change in GERD patients.21-24
Correa et al found that GERD patients
had a higher incidence of sour taste in
the oral cavity.21 Taste change in GERD
patients has been determined to be due to
the regurgitation of the gastric contents
into the mouth, which tends to present a
sour, salty, bitter, or acidic taste.22-24
Burning mouth sensation
Regurgitated acid and the insufficient
production of saliva may cause defective
clearance and neutralization of acid that
may result in burning mouth sensation.16
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As stated earlier, the incidence of burning
mouth sensation in this study was found
to be statistically significant. However,
this was not in accordance with previous
studies. Venkataswamy Reddy and Di
Fede et al reported 48.3% and 43.2% of
incidences of burning mouth sensation,
respectively; neither value was deemed
statistically significant.6,12
Tooth sensitivity
The primary cause for tooth sensitivity in
GERD patients is tooth erosion. This can
be indicated by a variety of symptoms,
which include sensitivity to thermal or
sweet stimuli. Tooth sensitivity often
results in pain during mastication.1,25
Tooth erosion
The regurgitation of gastric acid into the
mouth has been connected with tooth erosion in a number of studies.26 Tooth erosion has been defined as the superficial loss
of the hard tissues of the teeth by a chemical process that does not involve the action
of bacteria.22 It is the predominant oral
manifestation of GERD. The early stages
of erosion are difficult to identify; the only
sign may be a barely noticeable loss of surface luster on clean, dry enamel.1,27
Erosion of the posterior teeth involving
lingual and occlusal surfaces may suggest
GERD, whereas erosion on the lingual
surfaces of anterior teeth has been noted
in bulimic patients, and patients exposed
to acids from external sources mostly
present with damage on the labial surfaces of the anterior teeth, with severity
decreasing posteriorly.1,28,29
The reported prevalence of dental erosion in GERD patients varies widely.
However, the findings of this study are in
accordance with previous studies.14,30 In
a study by Fennerty, patients who either
exhibited symptoms of GERD or were
clinically diagnosed with the disease had
a statistically higher frequency of tooth
erosion when compared with controls (P =
0.0001).14 A cross-sectional study by Pace
et al evaluated 20 adult dentate subjects to
find whether the loss of tooth structure was
a result of dental erosion and GERD.30 The
results showed that the subjects diagnosed
with GERD had significantly higher tooth
wear index scores compared to controls,
indicating that a relationship exists between
loss of tooth structure and GERD.30
General Dentistry
May/June 2015
e29
Medical Health History/Factors Oral manifestations in gastroesophageal reflux disease
Tooth erosion and salivary changes
The prevalence of dental erosion in
patients with GERD varies widely, and
could be influenced by individual factors,
such as differences in the defensive mechanism to acid reflux, including salivary flow
rate, buffering capacity, and pH.27
Salivary flow rate increases when acid
from intrinsic or extrinsic sources enters
the mouth.4 It has also been found that
esophageal acid infusion increases salivary
flow. Hence, salivary flow is directly
related to acid concentration. While it
has been shown that decreased stimulated
salivary flow rate and salivary hypofunction are present in GERD, no definitive
conclusions have been established regarding the causation.16
A number of investigators have hypothesized that a low salivary flow rate is an
important modifying factor affecting
dental erosion. The risk of erosion in
patients with low unstimulated salivary
flow rate is 5 times the risk in patients
with normal flow rates.11,15
The cross-sectional study by Campisi et
al was conducted on 120 GERD patients
and 98 healthy subjects in order to evaluate their salivary parameters (basal flow
rate, stimulated flow rate, pH, and sodium
and potassium concentrations).16 Both the
GERD and control groups were found to
have similar basal flow rates, with mean
values of 0.39401 and 0.3185, respectively. However, there was a difference in
stimulated salivary flow, with mean values
of 0.48718 and 0.6108, respectively. The
authors concluded that salivary secretion is
altered in GERD patients and emphasized
the need for further investigation in order
to define the role of saliva in the etiopathogenesis of GERD.16
Buffering capacity
The buffering capacity of saliva refers to
its ability to resist change in pH when
acid is added to it. This property is
largely due to the bicarbonate content
of the saliva, which in turn is dependent
on the salivary flow rate. If the buffering capacity is impaired (as is the case
in GERD patients), the acid exposure is
prolonged, which results in oral tissue
damage.4 Silva et al evaluated the salivary
parameters (buffering capacity, pH,
and slow rate) of 62 patients with erosion compared to 50 randomly selected
e30
May/June 2015
General Dentistry
control subjects with no evidence of tooth
erosion.22 The erosion patients had low
salivary buffering capacity in comparison
to the controls; this difference was highly
significant (P < 0.001). There was no statistically significant difference in salivary
flow rate and pH between the erosion
patients and controls.26 Meurman et al
evaluated 117 patients for oral, dental,
and salivary findings.8 The authors found
that 28 patients had erosion, and there
was no statistical difference in resting
and stimulated salivary flow rate in
patients with erosion and those without
erosion (controls). However, the patients
with erosion had a low buffering capacity
compared with the controls. The difference was not statistically significance
(P = 0.008).8 In the present study, the
salivary buffering capacity and flow
rate were not examined. However, the
unstimulated salivary pH was analyzed
after the 12-hour fast.
Salivary pH
The patients in this study exhibited a
decrease in the mean salivary pH as the
duration and GERD grade increased.
In addition, the severity of tooth erosion
increased as the GERD grade increased.
The inorganic material of teeth starts to
dissolve when saliva ceases to be saturated
with calcium and phosphate. This takes
place below the critical pH level, which
has been defined as 5.5.11,22,26 Hence, the
exposure to the acid found in GERD is
a necessary condition to provoke dental
erosion, whereas other factors could influence the evolution of the lesion.27
The data in the present study data
were not in accordance with the study by
Campisi et al, which showed that there was
an increase in mean salivary pH (8.9) in the
test group compared with the healthy controls, who had a mean salivary pH of 7.8.16
Mouth sores
As previously mentioned, the presence of
mouth sores in this study was found to be
statistically significant. In a cross-sectional
study of 50 patients with GERD compared with 50 controls, Correa et al found
that 21 of the GERD patients complained
of frequent episodes of canker sores. The
authors concluded that patients with
GERD present with a higher incidence of
canker sores.21
www.agd.org
Myofascial pain
Tooth erosion predisposes the teeth to
attrition and abrasion, leading to a tendency to fracture. This in turn causes a
progressive loss in the vertical dimension
of occlusion, impairing both chewing and
phonetics.1,4,9 This cumulative damage to
the masticatory system is indicated by a
variety of symptoms, such as pain on mastication, loss of masticatory efficacy, and
TMD, eventually predisposing the patient
to myofascial pain.1 However, in the present study, none of the patients exhibited
TMD or myofascial pain.
Summary
The overall observation of the present
study reveals that tooth erosion is a significant clinical sign in GERD patients, which
can be related to the reduction of salivary
pH. Dry mouth, taste change, burning
mouth sensation, mouth sores, tooth erosion, and tooth sensitivity are significant
symptomatic manifestations of GERD,
and the results of this study presented
clinically significant incidences of these.
The severity of tooth erosion increased
as the GERD grade and the duration of
GERD increased. This can be explained by
the fact that as the GERD grade increases,
salivary pH decreases, which in turn predisposes the teeth to erosion.
This study also explored the association between general and oral health, and
provided valuable information regarding
the effects of GERD on the oral cavity. It
is critical that general dentists collaborate
with the GERD patient’s gastroenterologist to identify the oral involvement of
this disease. Dentists should also refer any
patient with unexplainable tooth erosion to
a gastroenterologist to investigate whether
GERD is a factor. This interdependent
rapport between dental and medical professionals will help to provide optimal oral
and general health to the patient, thereby
improving the patient’s quality of life.
Author information
Dr. Preetha is a lecturer, Department of
Oral Medicine and Radiology, Faculty
of Dentistry, AIMST University, Kedah,
Malaysia. Dr. Sujatha is a professor,
Department of Oral Medicine and
Radiology, The Oxford Dental College,
Bangalore, India, where Drs. Patil and
Hegde are readers.
References
1. Farrokhi, F, Vaezi MF. Extra-esophageal manifestations
of gastroesophageal reflux disease. Oral Dis. 2007;
13(4):349-359.
2. Ali DA, Brown RS, Rodriguez LO, Moody EL, Nasr MF.
Dental erosion caused by silent gastroesophageal reflux disease. J Am Dent Assoc. 2002;133(6):734-737;
quiz 768-769.
3. Kasper DL, Braunwald E, Hauser S, Longo D, Jameson
LJ, Fauci AS. Harrison’s Principles of Internal Medicine.
16th ed. New York: McGraw-Hill Professional; 2004.
4. Gandara BK, Truelove, EL. Diagnosis and management
of dental erosion. J Contemp Dent Pract. 1999;1(1):
16-23.
5. Rosner B. Fundamentals of Biostatistics. 5th ed. Pacific
Grove, CA: Duxbury; 2004:80-240.
6. Venkataswamy Reddy M. Statistics for Mental Health
Care Research. Bangalore, India: NIMHANS; 2002:
108-144.
7. Sunder Rao PSS, Richard J. An Introduction to Biostatistics, a Manual for Students in Health Sciences. 4th
ed. New Delhi: Prentice Hall; 2000:86-160.
8. Meurman JH, Toskala J, Nuutinen P, Klemetti E. Oral
and dental manifestations in gastroesophageal reflux
disease. Oral Surg Oral Med Oral Pathol. 1994;78(5):
583-589.
9. Huber MA. Gastrointestinal illnesses and their effects
on the oral cavity. Oral Maxillofac Surg Clin North
Am. 2008;20(4):625-634.
10. Moore JM, Vaezi MF. Extraesophageal manifestations
of gastroesophageal reflux disease: real or imagined?
Curr Opin Gastroenterol. 2010;26(4):389-394.
11. Liberali S. Oral impact of gastro-oesophageal reflux disease: a case report. Aust Dent J. 2008;53(2):176-179.
12. Di Fede O, Di Liberto C, Occhipinti G, et al. Oral manifestations in patients with gastro-oesophageal reflux
disease: a single-center case-control study. J Oral
Pathol Med. 2008;37(6):336-340.
13. Moshkowitz M, Horowitz N, Leshno M, Halpern Z. Halitosis and gastroesophageal reflux disease: a possible
association. Oral Dis. 2007;13(6):581-585.
14. Fennerty MB. Extraesophageal gastroesophageal reflux disease. Presentations and approach to treatment.
Gastroenterol Clin North Am. 1999;28(4):861-873.
15. Lazarchik DA, Filler SJ. Effects of gastroesophageal
reflux on the oral cavity. Am J Med. 1997;103(5A):
107S-113S.
16. Campisi G, Lo Russo L, Di Liberto C, et al. Saliva variations in gastro-esophageal reflux disease. J Dent.
2008;36(4):268-271.
17. Mihailopol CF, Lacatusu S, Codreanu CM, Pancu G,
Topoliceanu C, Ghiorghe CA. Correlations between
dental erosion severity and salivary factor in patients
with gastroesophageal reflux disease. Rom J Oral
Rehabil. 2011;3(4):63-66.
18. Bouchoucha M, Callais F, Renard P, Ekindjian OG,
Cugnenc PH, Barbier JP. Relationship between acid
neutralization capacity of saliva and gastro-oesophageal reflux. Arch Physiol Biochem.1997;105(1):19-26.
19. Helm JF. Role of saliva in esophageal function and disease. Dysphagia. 1989;4(2):76–84.
20. Moazzez R, Bartlett D, Anggiansah A. Dental erosion,
gastro-oesophageal reflux disease and saliva: how are
they related? J Dent. 2004;32(6):489-494.
21. Correa MC, Lerco MM, Henry MA. Study in oral cavity
alterations in patients with gastroesophageal reflux
disease [in Portuguese]. Arq Gastroenterol. 2008;
45(2):132-136.
22. Silva MA, Damante JH, Stipp AC, Tolentino MM, Carlotto PR, Fleury RN. Gastroesophageal reflux disease:
new oral findings. Oral Surg Oral Med Oral Pathol Oral
Radiol Endod. 2001;91(3):301-310.
23. Leader D. Bad Tastes in Your Mouth in the Morning?
Patients Beware of GERD! Available at: http://www.
dentalindia.com/badtaste.html#.VGTaSzTF_hk. Accessed November 13, 2014.
www.agd.org
24. National Institutes of Health. Gastroesophageal Reflux
Disease. Available at: http://www.nlm.nih.gov/medlineplus/ency/article/000265.htm. Accessed March 5,
2015.
25. Eccles JD. Erosion of teeth by gastric contents. Lancet.
1978:2(8087):479.
26. Firouzei MS, Khazaei S, Afghari P, et al. Gastroesophageal reflux disease and tooth erosion: SEPAHAN systematic review No. 10. Dent Rest J (Isfahan). 2011;
8(Suppl 1):S9-S14.
27. Munoz JV, Herreros B, Sanchiz V, et al. Dental and periodontal lesions in patients with gastro-esophageal
reflux disease. Dig Liver Dis. 2003;35(7):461-467.
28. Groen JN, Smout AJ. Supra-oesophageal manifestations of gastro-oesophageal reflux disease. Eur J Gastroenterol Hepatol. 2003;15(12):1339-1350.
29. Gregory-Head BL, Curtis DA, Kim L, Cello J. Evaluation
of dental erosion in patients with gastroesophageal
reflux disease. J Prosthet Dent. 2000;83(6):675-680.
30. Pace F, Pallotta S, Tonini M, Vakil N, Bianchi Porro G.
Systematic review: gastro-oesophageal reflux disease
and dental lesions. Aliment Pharmacol Ther. 2008;
27(12):1179-1186.
Manufacturers
GlaxoSmithKline, Research Triangle Park, NC
888.825.5249, us.gsk.com
MedCalc Software bvba, Ostend, Belgium
32.5944.3843, www.medcalc.org
SPSS, Inc., Quarry Bay, Hong Kong
852.2811.9662, www.spss.com
StataCorp LP, College Station, TX
800.782.8272, www.stata.com
Systat Software, Inc., San Jose, CA
800.797.7401, www.systat.com
General Dentistry
May/June 2015
e31
Prosthodontics/Removable
Use of a bite registration vinyl polysiloxane
material to identify denture flange
overextension and/or excessive border
thickness in removable prosthodontics
C. Brent Haeberle, DMD n Amara Abreu, DDS, MSD n Kurt Metzler, DDS, MS
Vinyl polysiloxane (VPS) has multiple applications in prosthodontics.
This article describes how a bite registration fast-set VPS material
was used to identify length overextension and/or excessive border
thickness of denture flanges. In addition, the advantages of VPS over
conventional materials are presented.
P
roper fitting is critical for the successful treatment of patients requiring removable prosthodontics. The
clinician must evaluate the prosthesis
critically to ensure that insertion and
removal are comfortable and atraumatic.
The postdelivery evaluation of a patient’s
complete or partial denture might seem a
fairly straightforward procedure since there
are techniques used commonly to identify
pressure areas. However, it actually is more
complex, as it relies on many variables,
including the dentist’s ability to discern
normal tissue from mucosa that has
been irritated by the prosthesis.1,2 When
diagnosing the cause of a denture sore or
irritation, a dentist must be aware of the
anatomical variations among patients, each
patient’s ability to tolerate the wearing
of a denture, the patient’s comfort level
with the daily use of a prosthesis, and the
patient’s psychological profile. Common
complaints associated with a newly fabricated prosthesis include pain with function, rubbing or chafing of sensitive areas,
and cheek or lip biting.1,2
In the authors’ experience, the first step
during an insertion appointment should
involve evaluating and adjusting the tissue
side of the new prosthesis. In areas with
mucosal or bony undercuts, relieving the
intaglio surface of the denture will prevent
lacerating or even stripping the soft tissue
that covers the underlying bone. Pressure
areas left untreated beneath a removable
prosthesis can result in extreme patient
discomfort, diminished blood supply, and
loss of bony support.
e32
May/June 2015
General Dentistry
Received: June 20, 2013
Accepted: September 25, 2013
Key words: vinyl polysiloxane, overextension, denture flanges
Once the prosthesis has a positive
and stable seat, the next step is to evaluate the borders and determine if their
extension is adequate and the contours
accommodate to the available space in
the vestibule. A properly formed denture
border should be smooth, rounded, and
well-adapted to the vestibule. A variety of
disclosing media, such as commercially
available pastes and waxes, aid the dentist
in the delivery process. Overextended
flanges can be evaluated by instructing
the patient to make certain movements
of the facial musculature with the disclosing media in place. Thin borders or
overextended flanges can cause lesions in
the mucosa.1,2 Common areas of irritation include hamular notches, posterior
palatal tissue, and areas associated with
the mylohyoid muscle. Denture borders
that fall short of filling the vestibule
are another source of concern. These
shortened borders can interfere with
the peripheral seal and affect retention,
resulting in denture movement and
instability, and eventually leading to
mucosal soreness.1,2
An ill-fitting denture can affect retention, stability, and occlusion. Digital
palpation of ridges and careful examination can help with proper diagnosis of this
dilemma. Jankelson classified pressure
areas into 3 parts: the peripheral border,
the basal seat, and the intaglio surface.2
Any problem that affects any one of these
zones will compromise the success of a
new prosthesis. It is imperative that a
clinician take the time to evaluate and
www.agd.org
make any necessary adjustments to a new
prosthesis to maximize the fit and thus
minimize tissue irritation.1,2
New dentures require scrutiny at the
time of delivery since the fabrication process can contribute to minor changes on
the intaglio surface. These changes can be
caused by undetermined pressure during
the final impression procedure, overextension of border molding, irregular or rough
finishing on the denture intaglio surface,
tooth shifting, and other distortions associated with the fabrication process of the
denture acrylic.1,2
The final step in the insertion procedure
is occlusal correction, which ideally involves
doing a clinical remount.1,2 This procedure
helps to identify occlusal discrepancies
and allows the clinician to achieve occlusal
harmony, resulting in a more comfortable
prosthesis with improved function while
preserving supporting structures.
Vinyl polysiloxane (VPS) is an additionreaction silicone elastomer that has been
used in dentistry since the 1970s.3 Over
time, it has become a standard for replicating hard and soft tissues in great detail
and has been used in teaching institutions,
hospitals, and dental offices for the construction of fixed, removable, implant, and
maxillofacial prosthodontics.3
The literature has covered the many uses
of VPS, such as impressions and border
molding.3,4 VPS also has been used for
sealing access of implant screws, various
aspects of maxillofacial prosthodontic procedures, capturing loose tissue in a nondistorted state, establishing bite registration in
Fig. 1. VPS bite registration material is expressed onto the denture
flange.
Fig. 2. The denture flange after insertion into a patient’s mouth.
Displaced material is considered overextension of the flange.
Fig. 3. Clinician marking an area of show-through with a pencil.
Fig. 4. Adjusted denture border.
fixed and removable prosthodontics, and a
blockout material for extraction sites before
relining immediate dentures.5-9 Dentists
also may use VPS to facilitate orientation
of the maxilla in a facebow transfer, to
determine occlusal clearance when preparing teeth for full coverage crowns, to place
attachments in overdenture situations, and
to function as a blockout material for clinical impressions.5-9
This article describes the technique of
applying bite registration fast-set VPS to
the denture border at either delivery or
the follow-up appointment in order to
identify length overextension and/or excessive border thickness of the denture flange.
This alternative material can improve and
facilitate the adjustment process.
Traditionally, dentists have used a variety
of commercially available pastes and waxes
to evaluate pressure areas and denture
borders at the time of insertion. The
bite registration fast-set VPS technique
described in this article has advantages
over more conventional methods (such
as pressure-indicating paste or disclosing
waxes).10,11 There is less chance of false
positives or areas being easily removed by
insertion. The use of bite registration fastset VPS is more efficient since the material can usually be removed in one piece
prior to adjustment. The need to clean
wax or paste from a bur—which can be
tedious and time-consuming—is virtually
eliminated. Some clinicians may consider
the fast-set VPS technique as an expensive
alternative to the traditional routes of
evaluating pressure areas and denture
borders; however, some of the benefits of
this technique—such as the more assertive
modifications to the denture flange and
less adjustment time involved in follow-up
appointments—should be considered.
Procedure
The procedure is very simple. First, the
area in question is dried, and a sufficient
length of VPS bite registration material is
www.agd.org
expressed onto the denture flange (Fig. 1).
Next, the denture is placed and seated, and
the border molding is performed on that
particular aspect of the prosthesis. After
15-30 seconds, the denture is removed
and inspected. Any displaced material
is considered an overextension (Fig. 2).
Since no adhesive has been applied, the
area of show-through is marked with a
pencil in case the material peels off during
the adjustment (Fig. 3). This procedure
is repeated until the denture borders have
adequate length and thickness, so that
no material is displaced from the borders
when the denture is placed (Fig. 4).
Discussion
This technique is suggested as an adjunctive procedure for detecting overextended
borders of complete dental prostheses.
As stated previously, pressure-indicating
pastes and/or disclosing waxes have
been used for many years with excellent
diagnostic results. Painting a paste on the
General Dentistry
May/June 2015
e33
Prosthodontics/Removable Use of a bite registration vinyl polysiloxane material in removable prosthodontics
intaglio surface of a removable prosthesis
generally identifies soft tissue lesions associated with denture irritation by displacing
the paste from the denture base in areas of
tissue contact. However, the formulas of
indicating paste vary between manufacturers, and these variances can affect their
rate of flow under pressure.12
Using a disclosing wax to determine
flange overextension aids in visualizing
affected vestibular tissue since the material
is displaced from the border in areas of
contact with the tissue.13 These materials
are inexpensive and can be applied easily to
removable prostheses. However, false positives may be encountered upon insertion
and/or removal; as a result, the material is
dragged from the prosthesis base into areas
of soft tissue or bone undercuts.13 In addition, the interpretation of pressure areas
with complete dentures can vary among
individual dentists, depending on their
particular technique and level of experience.
Phoenix & DeFreest noted that the viscosity of some commonly marketed disclosing
waxes may not be adequate for effective
evaluation of the peripheral border of a
removable prosthesis.13
The authors have found bite registration
fast-set VPS to be helpful when instructing
predoctoral dental students and postdoctoral dental residents on troubleshooting
post-insertion adjustments for patients
wearing removable complete or partial
dental prostheses. The bite registration
fast-set VPS has a heavy consistency that
allows it to remain in place on the prosthesis border during clinical manipulation. At
the same time, the material is soft enough
to flow and allow for partial removal when
found in areas of pressure to the tissue.
Many institutions use either modeling
compound or heavy body VPS to teach
border molding.14 Various materials and
their effects on postinsertion adjustments
have been evaluated in the literature.14-16 A
2003 study by Drago examined 78 edentulous patients who underwent border
molding and determined that the number
of denture adjustments was the same
whether modeling compound or VPS was
used.14 In the authors’ experience, only
conventional methods for the identification of excessive border thickness or areas
of overextension tend to be covered in
dental schools. The common false-positive
marks inherent in these methods may lead
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May/June 2015
General Dentistry
clinicians-in-training to spend additional
time with insertion and postinsertion
appointments. Recent studies have shown
that the majority of dental schools utilize a
selective pressure technique for edentulous
final impressions using a border-molded
custom impression tray.4,15,16 Some schools
have proposed a mucostatic technique
for their denture patients, which usually
results in a comparatively shorter flange.15
However, in the authors’ experience, the
bite registration fast-set VPS technique can
identify overextended as well as underextended flange length. Depending on the
symptoms associated with the particular
flange dimension (whether over- or underextended), procedures could be recommended to correct such a finding.
The authors have observed removable prosthetics with inadequate denture
borders in some of their patients. Upon
questioning, the patient often speaks of
numerous follow-up appointments with
his/her previous dentist, who had then
adjusted the denture in the area where the
patient felt soreness. These adjustments
often are performed without a systematic
and thorough examination of the patient’s
edentulous arch or an adequate diagnosis
to facilitate the proper course of treatment
and consequently may or may not alleviate
the soreness. A 1995 study by Yeoman &
Beyak determined that areas of denture
discomfort perceived by patients usually
are not actually the part of the prosthesis
that requires adjustment.16
It is imperative to polish the acrylic after
altering the pressure area or flange on a
denture base.17 Polishing restores the material to a much smoother surface, which
provides a comfortable fit for the patient.
Previous studies have mentioned that denture base material left in a roughened state
is prone to bacterial accumulation and
plaque formation.17-21 Pathogens that can
colonize on the acrylic include Candida
albicans and Streptococcus oralis. Chairside
polishing kits or pumice on a wet rag
wheel can restore the denture acrylic to a
smooth surface, reducing the likelihood of
bacterial adhesion.
After the first or second post-delivery
appointment, the cause of tissue irritation
usually can be traced to some minor malocclusion. Some clinicians favor a settling
period for the dentures before refining
the occlusion. However, the literature has
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shown that performing a clinical remount
procedure at the time of delivery helps
minimize mucosal soreness and reduce
the frequency of return visits for adjustment.22,23 It is implicit that this procedure
will require more clinical time at the insertion appointment; however, it also allows
for accurate refinement of the occlusion
and ensures fewer post-insertion appointments. Intraoral occlusal adjustments are
not always reliable due to tissue resilience
and denture shifting, which can lead to
inaccurate markings on the teeth.
Regardless of the dentist’s methodology for providing a removable prosthetic
service to a patient, utilizing a bite registration fast-set VPS material to evaluate
flange shape and extension can be an
additional diagnostic aid during the
delivery and adjustment phase of removable prosthodontics.
Conclusion
The use of bite registration fast-set VPS
is an alternative technique for identifying length overextension and/or excessive
border thickness of denture flanges. As
with other techniques, its use has advantages and disadvantages.
Author information
Drs. Haeberle, Abreu, and Metzler are
assistant professors, Department of
Oral Rehabilitation, College of Dental
Medicine, Georgia Regents University of
Augusta.
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J Am Dent Assoc. 1962;64:521-531.
3. Johnson GH, Manci LA, Schwedhelm ER, Verhoef DR,
Lepe X. Clinical trial investigating success rates for
polyether and vinyl polysiloxane impressions made
with full-arch and dual-arch plastic trays. J Prosthet
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4. Petrie CS, Walker MP, Williams K. A survey of U.S.
prosthodontists and dental schools on the current materials and methods for final impressions for complete
denture prosthodontics. J Prosthodont. 2005;14(4):
253-262.
5. Hsu YT. Use of silicone impression material to block
out extraction sites prior to relining. J Prosthet Dent.
2005;94(3):303.
6. Chu KM, Tredwin CJ, Setchell DJ, Hems E. Effect of
screw hole filling on retention of implant crowns. Eur J
Prosthodont Restor Dent. 2005;13(4):154-158.
7. Kathuria N, Prasad R, Gupta N, Gulati M, Bhide SV. A
modified technique and simplified laboratory procedure for ocular prosthesis fabrication. J Prosthodont
Res. 2012;56(2):147-150.
8. Tan KM, Singer MT, Masri R, Driscoll C. Modified fluid wax impression for a severely resorbed edentulous
mandibular ridge. J Prosthet Dent. 2009;101(4):279282.
9. Campos AA, Nathanson D. Compressibility of two
polyvinyl siloxane interocclusal record materials and
its effect on mounted cast relationships. J Prosthet
Dent. 1999;82(4):456-461.
10. Logan GI, Nimmo A. The use of disclosing wax to evaluate denture extensions. J Prosthet Dent. 1984;51(2):
280-281.
11. Bookhan V, Owen CP. A comparison of the cost effectiveness of pressure-indicating materials and their
ability to detect pressure areas in complete dentures.
SADJ. 2001;56(5):228-232.
12. Stevenson-Moore P, Daly CH, Smith DE. Indicator
pastes: their behavior and use. J Prosthet Dent. 1979;
41(3):258-265.
13. Phoenix RD, DeFreest CF. An effective technique for
denture border evaluation. J Prosthodont. 1997;6(3):
215-217.
14. Drago CJ. A retrospective comparison of two definitive
impression techniques and their associated postinsertion adjustments in complete denture prosthodontics.
J Prosthodont. 2003;12(3):192-197.
15. Petropoulos V, Rashedi B. Current concepts and techniques in complete denture final impression procedures. J Prosthodont. 2003;12:280-287.
16. Yeoman LR, Beyak BL. Patient’s ability to localize adjustment sites on the mandibular denture. J Prosthet
Dent. 1995;73(6):542-547.
17. Kuhar M, Funduk N. Effects of polishing techniques on
the surface roughness of acrylic denture base resins.
J Prosthet Dent. 2005;93(1):76-85.
18. Radford DR, Sweet SP, Challacombe SJ, Walter JD. Adherence of Candida albicans to denture-base materials
with different surface finishes. J Dent. 1998;26(7):
577-583.
19. Morgan TD, Wilson M. The effects of surface roughness and type of denture acrylic on biofilm formation
by Streptococcus oralis in constant depth film fermentor. J Appl Microbiol. 2001;91(1):47-53.
20. Verran J, Maryan CJ. Retention of Candida albicans on
acrylic resin and silicone of different surface topography. J Prosthet Dent. 1997;77(5):535-539.
21. Hannig M. Transmission electron microscopy of early
plaque formation on dental materials in vivo. Eur J
Oral Sci. 1999;107(1):55-64.
22. Shigli K, Angadi GS, Hegde P. The effect of remount
procedures on patient comfort for complete denture
treatment. J Prosthet Dent. 2008;99(1):66-72.
23. Al-Quran FA. A clinical evaluation of the clinical remount procedure. J Contemp Dent Pract. 2005;15(6):
48-55.
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e35
Dental Materials
Low-shrinkage composites: an in vitro evaluation
of sealing ability after occlusal loading
Marcos O. Barceleiro, DDS, MSD, PhD n Giulia Marins Soares, DDS n Olivia Espindola, DDS n Sergio Kahn, DDS, MSD, PhD Isis Andrea Venturini Pola Poiate, DDS, MSD, PhD n Helio Rodrigues Sampaio Filho, DDS, MSD, PhD
The objective of this in vitro study was to compare the microleakage
of a flowable low-shrinkage-stress resin composite—in a Class II
fatigue-loading design when used as a 4 mm dentin replacement—to a
conventionally layered silorane-based resin composite. Eighty standardized
4 mm deep cavities, divided into 4 subgroups, were restored with the
2 tested materials. Half of the restorations were submitted to mechanical
loading, and all of the restorations were prepared for microleakage
evaluation. The evaluation of the marginal adaptation to dentin was
M
any studies have demonstrated the
significant improvements of composite restorations and that esthetic
posterior restorations may have relative
clinical success.1-3 However, other studies
have emphasized the clinical limitations
of resin-based composites (RBCs), mainly
with regards to polymerization shrinkage,
which may be related to undesirable clinical situations involving microleakage, marginal staining, gap formation, postoperative
sensitivity, enamel microcracks, cusp
deflection, and recurrent caries.4-6 New
restorative systems have been introduced
to the dental market with the promise
of reduced polymerization shrinkage by
lowering the polymerization rate; these
new systems— such as Filtek Silorane (3M
ESPE) and Surefil SDR Flow (DENTSPLY
Caulk)—could become substitutes for the
more commonly used methacrylate-based
monomer resin systems.
In vitro studies have reported significantly lower cusp deflection and microleakage after restoring posterior teeth
with a silorane-based resin composite
compared to methacrylate-based resins.7,8
However, other studies have shown negative results when evaluating nanoleakage
in posterior restorations using siloranebased composites.9,10 Additionally, Filtek
Silorane has not provided better results
when compared to methacrylate-based
materials in clinical investigations.11-13
Surefil SDR Flow (SDR) was introduced
to the market as a flowable resin composite
with the claim that it would allow for a
4 mm bulk placement in 1 layer due to
e36
May/June 2015
General Dentistry
performed with scanning electron microscopy. The results showed that
both silorane-based composite groups had higher rates of microleakage
in comparison to the low-shrinkage-stress resin composite groups.
Received: August 23, 2013
Revised: November 27, 2013
Accepted: March 6, 2014
Key words: low-shrinkage composite, silorane, occlusal loading
reduced polymerization stress, although
it does require a 2 mm cover layer of
conventional resin composite for optimal
success.14-16 Some studies have shown
that the marginal integrity in enamel
and dentin for restorations using SDR is
comparable to that created with traditional
composites.17 There are not many studies describing the relevant parameters for
SDR; however, its polymerization stress
has reportedly been considerably lower
compared to those of conventional flowable materials.14 The measured mechanical
properties place the bulk-fill resin composites between the nanohybrid/microhybrid
resin composites and the flowable resin
composites, suggesting a similar or even
inferior clinical behavior of bulk-fill RBCs
when compared to nanohybrid and microhybrid resin composites.16 According to
some authors, curing a resin composite in
a 4 mm bulk increment for 20 seconds can
be recommended.18
Therefore, the objective of the present
study was to compare microleakage of the
flowable low-shrinkage-stress resin composite, SDR, to a conventionally layered
silorane-based resin composite, Filtek
Silorane, when used as a 4 mm dentin
replacement in a Class II fatigue-loading
design. The evaluation of the marginal
adaptation to dentin was performed with
scanning electron microscopy (SEM).
The null hypotheses tested were that
there would be no significant differences
in the microleakage and hybrid layer
formation between the materials tested
and there would be no differences in the
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marginal and internal integrities of the
dentin margins in the Class II cavities that
were restored with the tested materials
before and after fatigue loading.
Materials and methods
Eighty intact, noncarious, unrestored,
human third molars, extracted for therapeutic reasons with the informed consent
of the patients and with the approval of
the Serra dos Orgaos University Ethics
Committee (Teresopolis, Brazil), were
stored in an aqueous solution of 0.5%
chloramine T at 4°C for up to 30 days.
The teeth were debrided of residual plaque
and calculus and then examined under an
optical microscope at 20X magnification
to ensure that they were free of defects.
Eighty standardized Class II mesiooccluso-distal cavity preparations 3 mm
buccolingually, 4 mm occlusally, with the
proximal margins located 1-2 mm below
the cementoenamel junction (CEJ) were
performed. The cavities were cut using
coarse diamond burs under profuse water
irrigation (No. 2143, KG Sorensen). The
diamond burs were changed after every
3 preparations. In order to deliver results
that would be comparable to previous
studies, the inner angles of the cavities were
rounded, and the margins were not beveled.
The teeth were divided into 2 groups,
control (without occlusal loading) and
test (with occlusal loading); each group
was divided into 2 subgroups according to
the material used: Filtek Silorane or SDR.
Table 1 lists the materials used in this
study and their manufacturers.
Table 1. Materials used in the restorations, manufacturers, and chemical compositions.
Group Occlusal loading Material (batch)
1
No
2
Yes
3
No
4
Yes
Manufacturer
Filtek Silorane (8BH) 3M ESPE
Surefil SDR Flow
(100407)
After cavity preparation, the teeth were
cleaned with a low-speed handpiece for
30 seconds, using a fine powder of pumice
in a rubber cup. An individual metallic
matrix fixed by a matrix retainer was used
to create the lost proximal wall. The teeth
were then restored according to the restoration material used.
Filtek Silorane (Groups 1 and 2)
Cavities were conditioned with 37% phosphoric acid (3M ESPE) for 30 seconds,
exclusively on the enamel, as indicated
by the manufacturer.19 The surfaces were
rinsed with distilled water for 30 seconds
and gently dried with oil- and dust-free
air for 2 seconds. Next, the Filtek Silorane
Adhesive System was applied to the entire
cavity, enamel, and dentin, according to the
manufacturer’s instructions.19 A thin layer
of the primer was applied with a brush for
15 seconds. The solvent was removed with
oil- and dust-free air jets for 2 seconds, and
the surface was light cured for 10 seconds
with an LED light-curing unit (Olsen
Industria e Comercio S/A). The intensity
of the light was checked periodically with
a radiometer (Kerr Corporation) to ensure
that 650 mW/cm2 was constantly delivered
during the experimental procedures. A thin
layer of the adhesive was then applied and
immediately dried, similar to the first layer,
and the surface was light cured for 10 seconds. The Filtek Silorane was then applied
twice in 2 mm increments using a bulk layering technique. Each increment was light
cured for 40 seconds. After restoration, the
samples were stored for 7 days in distilled
water at 37°C.
Surefil SDR Flow (Groups 3 and 4)
The cavities were conditioned with 37%
phosphoric acid for 30 seconds on the
enamel and 15 seconds on the dentin. The
Resin matrix
Filler
3,4-Epoxycyclohexylethylcyclopolymethylsiloxane, bis-3,
4-epoxycyclohexylethylphenylmethylsilane, yttrium fluoride
(15%), camphorquinone, iodine salt, stabilizers, and pigments
Silanized quartz particles:
50% vol, 70% weight
DENTSPLY Caulk Modified urethane dimethacrylate, triethylene glycol
dimethacrylate, and ethoxylated bisphenol-A-dimethacrylate
surfaces were rinsed with distilled water
for 30 seconds and then gently dried with
oil- and dust-free air for 2 seconds. The
XP Bond Adhesive System (DENTSPLY
Caulk) was applied according to the manufacturer’s instructions.20 A thin layer of the
product was applied with a brush and left
undisturbed for 30 seconds. The solvent
was removed with oil- and dust-free air for
2 seconds. An additional layer of the adhesive was applied and immediately dried,
similar to the first layer, and the surface was
light cured for 10 seconds. SDR was then
placed in a single 3 mm increment using
a bulk layering technique. The increment
was light cured for 40 seconds. Then a
1 mm increment of Esthet X (DENTSPLY
International) was placed to complete the
cavity restoration and was light cured for 40
seconds. The 1 mm increment was contrary
to the manufacturer’s 2 mm recommendation.21 After restoration, the samples were
stored for 7 days in distilled water at 37°C.
General procedure
After the cavities were filled, the test group
was prepared for mechanical loading
as follows. The roots were coated with
melted wax up to 2 mm below the CEJ.
A polyvinyl chloride (PVC) cylindrical
tube (Tigre S/A), 21 mm diameter x
25 mm length, was used to contain the
teeth in autopolymerizing acrylic resin
(Artigos Odontologicos Classico Ltda)
up to the wax level (2 mm below the
CEJ). A surveyor (Bio-Art Equipamentos
Odontologicos Ltda.) was used to ensure
that the teeth were included in the PVC
tube with the cusps parallel to the base.
Thus, the load coming from the test
equipment (EMIC DL 500 MF, EMIC
Equipamentos e Sistemas de Ensaio LTDA)
was equally distributed among the cusps.
The teeth were then removed from the
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Ba-Al-F-B-Si glass and
St-Al-F-Si glass
acrylic resin, and the wax was substituted
with silicone (Express XT, 3M ESPE). The
excess silicone was removed with a Le Cron
spatula up to the area previously marked
as the fulcrum (2 mm below the CEJ).
After preparation, the teeth underwent
4000 loads at 150 N with each load lasting
1 second, using a universal testing machine
controlled with a software program (TESC
version 1.08, EMIC Equipamentos e
Sistemas de Ensaio LTDA).
Microleakage evaluation
All of the specimens were immersed in a
50% silver nitrate dyeing solution for 4
hours. The teeth were then longitudinally
sectioned with a mesiodistal cut, using a
low-speed diamond saw (KG Sorensen)
under irrigation. As a follow-up procedure,
2 precalibrated examiners evaluated the
tooth halves to evaluate the amount of dye
microleakage using 40X magnification.
The microleakage was scored using the
following scale: 0, no leakage; 1, leakage
up to the CEJ; 2, leakage beyond the CEJ
without reaching the axial wall; and 3,
leakage reaching the axial wall.
Statistical analysis was performed
using SPSS, Version 12 (SPSS, Inc.) for
Windows (Microsoft). Nonparametric
tests were used (Kruskal-Wallis test, Dunn
test) for pairwise comparisons at a 95%
significance level.
SEM evaluation
After 7 days, a transverse section was made
5 mm below the tooth/composite interface,
using the diamond saw, and the roots of the
sections were discarded. The 2 sectioned
halves, formed of enamel, dentin, adhesive
system, and resin composite, were hand
polished on wet 600 grit silicon carbide
paper (Saint-Gobain Abrasives) and then
finished with a felt wheel placed in a Praxis
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Dental Materials Low-shrinkage composites: an in vitro evaluation of sealing ability after occlusal loading
Fig. 1. Absence of hybrid layer and resin tags in a specimen
restored with the Filtek Silorane system with occlusal loading.
polishing device. An alumina polishing
paste with 0.5 µm particles (AP-Paste SQ,
Struers, Inc.) was used until no grooves were
observed at 50X magnification. The sections
were then conditioned in distilled water.
After 7 days, 1 section of each previously
formed pair was gently decalcified using
37% phosphoric acid for 10 seconds,
rinsed with distilled water, and then deproteinized with 3% sodium hypochlorite for
60 seconds.7 The sections were rinsed with
distilled water, placed on aluminum stubs,
and sputter-coated with gold (Edwards
Coater S150B, Edwards Limited).
The samples were then evaluated under
an LEO 1450VP scanning electron
microscope (Carl Zeiss Microscopy).
Microphotographs of the hybrid layers
were taken at 1000X magnification.
Results
Microleakage scores were evaluated
using the Kruskal-Wallis test (95% significance level). There was a statistically
significant difference between the groups
(H = 18.015, with 3 degrees of freedom;
P = 0.000). Score values were then treated
by Dunn’s multiple comparisons test (95%
significance level). The mean scores of
each group are shown in Table 2.
The Dunn test showed that there was
an important statistically significant difference between Groups 1 and 2 and
between Groups 1 and 4. There was no
statistically significant difference between
groups 3 and 4. Thus, the final microleakage evaluation was Group 2 > Group 1 >
Group 4 = Group 3.
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May/June 2015
General Dentistry
Fig. 2. Portion of the hybrid layer and resin tags in a specimen
restored with Surefil SDR Flow and Esthet X with occlusal loading.
When evaluated under SEM, the hybrid
layer images in Group 4 were compatible with other study images and were
considered of good quality. However,
Group 2 presented images of bond failures and a lack of resin tag formation.
Figures 1 and 2 are images of specimens
from Groups 2 and 4, respectively.
Table 2. Mean microleakage scores
for the groups in this study.
Group
1
Mean score
2.26
2
2.97
3
1.20
4
1.43
Discussion
The objective of this study was to evaluate the sealing ability of 2 low-shrinkage
composite restoration systems, before and
after occlusal loading, using a microleakage test and an SEM evaluation. As
shown in Table 2, greater microleakage
scores were found in the samples restored
with Filtek Silorane both with and
without occlusal loading (Groups 2 and
1, respectively). Although the adhesive
system of Filtek Silorane promotes good
bond strength, nanoleakage remains a
characteristic problem of this system.9
In a previous study, the Filtek Silorane
adhesive system provided a tight, stable,
and water-resistant adhesion to dentin.10
However, those same authors could not
see resin tags in the hybrid layer formed
by this adhesive system, as found in the
present study and other studies.10,22,23
With regard to the SDR resin flow
system, the results were satisfactory, showing low microleakage scores in the occlusal
loading group (Group 4) and the absence
of microleakage in the group without
occlusal loading (Group 3) (Table 2).
These results agree with those obtained in
another study that revealed the adhesive
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effectiveness and marginal integrity for
enamel and dentin when compared with
5 other restorative systems.17
When evaluated with SEM, the hybrid
layer was considered uniform and regular.
These results are in accordance with the
results of other authors, who stated that
the combination of SDR with a final
layer of conventional resin composite
apparently showed no lack of adhesive
performance in terms of marginal quality
to enamel and dentin and presented with
good internal dentin adaptation.17
The Dunn test showed that the Filtek
Silorane microleakage was statistically
greater than the microleakage observed
with the SDR. Therefore, there was a
statistically significant difference between
the 2 materials, even when analyzed after
occlusal loading, meaning that the first
null hypothesis was rejected. When the
authors of this study evaluated the influence of occlusal loading in groups treated
with the same composite, a statistically
significant difference was found between
the groups, indicating that the second
null hypothesis was also rejected. An
interesting fact observed by the analysis of
Table 2 is that the microleakage of Group
3, SDR Flow with occlusal loading, was
significantly lower than that of Group 1,
Filtek without loading, indicating that
SDR Flow tends to be more resistant
to this occlusal challenge than Filtek
Silorane. The SDR was covered by a
layer of regular RBC—as directed by the
manufacturer’s instructions and also as
depicted in other studies that determined
that the manufacturers’ indication to
finish a bulk-fill RBC restoration by
adding a capping layer made of regular
RBCs is a necessity, since the values of
the indentation moduli and hardness
of particular materials (such as SDR)
were considerably below the mean values
measured for regular nanohybrid and
microhybrid RBCs.16 Therefore, there was
no means of actually comparing the tested
resins. In fact, the authors of this study
compared the restorative techniques using
the tested materials.
The authors of this study agree with
the findings of other studies that asserted
that—although clinical trials remain the
gold standard in evaluating the performance of dental materials—clinicians
must take into account the fact that
individual products under investigation
may not prove useful once clinical data
are collected.17,24,25 This situation is exacerbated by the delay between the points at
which clinical results are obtained and at
which they are published in peer-reviewed
journals. Thus, preclinical screening via
laboratory tests is still an important tool
for the evaluation of dentin adhesives,
allowing for the evaluation of many
experimental groups, unlike clinical studies, in which the number of variables must
be kept small.26 However, real clinical
practice in actual restorations and their
respective evaluations are required for the
final assessments of actual results. In the
same manner, evaluations with other types
of bulk-fill composites would be helpful
to give a better baseline to compare new
materials in order to evaluate if a new
material is an actual improvement over
older generations of materials.
Conclusion
Based on the results obtained in this
study, the silorane-based composite Filtek
Silorane has higher rates of microleakage,
requiring verification of the effectiveness
of the adhesive system indicated for use
with this composite by the manufacturer.
The best microleakage results were
found with Surefil SDR Flow. However,
randomized clinical trials are necessary to
verify the clinical use of this new material.
Author information
Drs. Barceleiro and Poiate are professors,
Department of Restorative Dentistry,
Fluminese Federal University, Nova
Friburgo, Brazil, where Drs. Soares and
Espindola are researchers in the Master
of Science program. Dr. Kahn is a professor in the Master of Science program,
Oral Rehabilitation Department, Veiga
de Almeida University, Rio de Janeiro,
Brazil. Dr. Sampaio Filho is a professor,
Department of Restorative Dentistry, Rio
de Janiero State University, Brazil.
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Manufacturers
Artigos Odontologicos Classico Ltda, Sao Paulo, Brazil
55.11.3022.2588, www.classico.com.br
Bio-Art Equipamentos Odontologicos Ltda.,
Sao Carlos, Brazil
55.16.3371.6502, www.bioart.com.br
Carl Zeiss Microscopy, Dublin, CA
800.442.4020, www.zeiss.com
DENTSPLY Caulk, Milford, DE
800.532.2855, www.caulk.com
DENTSPLY International, York, PA
800.877.0020, www.dentsply.com
General Dentistry
May/June 2015
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Dental Materials Low-shrinkage composites: an in vitro evaluation of sealing ability after occlusal loading
Edwards Limited, Sanborn, NY
800.848.9800, www.edwardsvacuum.com
EMIC Equipamentos e Sistemas de Ensaio LTDA,
San Jose dos Pinhais, Brazil
55.42.3035.9400, www.emic.com.br
Kerr Corporation, Orange, CA
800.537.7123, www.kerrdental.com
KG Sorensen, Cotia, Brazil
55.11.4777.1061, www.kgsorensen.com.br
Microsoft, Redmond, WA
425.882.8080, www.microsoft.com
Olsen Industria e Comercio S/A, Palhoca, Brazil
55.48.2106.6000, www.olsen.odo.br
Saint-Gobain Abrasives, Stephensville, TX
254.918.2313, www.nortonabrasives.com
SPSS, Inc., Chicago, IL
312.651.3000, www.spss.com
Struers, Inc., Westerville, OH
440.871.0071, www.struers.com
Tigre S/A, Joinville, Brazil
55.47.3441.5000, www.tigre.com
3M ESPE, St. Paul, MN
888.364.3577, solutions.3m.com
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May/June 2015
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