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Indefinite Orthodontic
Retention
A Peer-Reviewed Publication
Written by Michael Florman, DDS and Mahtab Partovi, DDS
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Educational Objectives
Upon completion of this course, the clinician will be able
to do the following:
1. Describe orthodontic relapse in detail and understand
how and why it occurs
2. Discuss normal growth and development as it pertains
to orthodontic relapse
3. Explain how the normal occlusal factors, muscle function, and soft-tissue forces keep teeth in their normal
positions as well as move teeth out of position
4. Understand the changes that occur after orthodontic
treatment, allowing the reader to grasp the importance
of indefinite retention
5. Assess the proper solutions to orthodontic relapses
and understand ideas on how all dentists can help their
patients prevent orthodontic relapse
6. Implement an orthodontic retention program
7. Create an income source while providing an invaluable
service to patients
Abstract
Many studies have been performed to ascertain if there is a
better way to move teeth that will reduce post-orthodontic
relapse. Relapse happens, and it may have very little to do
with the treatment mechanics or plan. Permanent retention is the only reliable way to keep the dental arches in a
position similar to the position they were in the day after
the patient’s braces were removed. Prevention of dental
relapse is possible if an interdisciplinary approach is developed. The responsibility for evaluating a patient’s postorthodontic occlusion rests in the hands of the dentists and
the hygienists who will care for them for the rest of their
lives. The orthodontist is not in this chain of professionals
until a problem returns, and the patient is being referred
back for re-treatment. Most orthodontic patients graduate
high school, move away to college, and lose touch with their
orthodontist. The general dental practice is the only line of
defense that exists to spread the message and provide the
retention services needed indefinitely.
Introduction
As a practicing orthodontist, I see many adults whose
chief complaint is crowding of the lower teeth. Many
times, upper crowding is also present, but to a lesser
degree. Many of the patients received orthodontic care
when they were younger and did not wear their retainers. Others have never had any orthodontic treatment
but complain that their lower teeth are suddenly becoming crowded.
What is being done to keep patients’ teeth straight
after they finish orthodontic treatment? What is being
done to keep teeth straight in patients who have never
had orthodontic treatment? Whose responsibility is it to
provide retention care to patients?
2
Vaden says that little is known about the changes in
orthodontic treatment results exceeding a decade after
treatment.1 Little states that no clinical findings seem to
predict relapse and that post-retention crowding of the
lower incisors is the first sign of the negative changes that
will ensue.2
Development and Aging
Skeletal and dental differences exist between boys and
girls. At ages 11 to 13, girls mature with a skeletal and
dental pattern similar to women. Boys mature by age 15
but can experience maturation changes that occur even
into their twenties.3 Latent mandibular growth can create
problems in patients (usually boys) who have completed
their orthodontic treatment or are currently in treatment.
Many patients end up with sagittal (anterior-posterior)
discrepancies requiring re-treatment, lengthened treatment times, or in some cases, the need for mandibular surgical setback. In post-treated patients, latent mandibular
growth can cause lower crowding and uprighting of the
lower incisors. Maxillary spacing can also occur due to the
force of the lower incisors pushing on the maxillary teeth.
Studying adults may help to determine whether the
post-orthodontic changes were caused primarily by orthodontic relapse or by the normal aging process. Akgul
studied the natural craniofacial changes in the third decade
of life:4
Skeletal Changes
Most changes occur in the vertical dimension, which are
expected due to the effects of gravity. Sagittal changes
were not significant. Anterior face height increased in both
males and females. Increases in lower face height were only
apparent in women. Total face height increases are caused
by the increase in lower facial height, caused by the continued eruption of the teeth. Facial convexity and ANB angle
increased significantly. Bishara concluded that the male
skeletal profi le increases in convexity because of increases
in prominence of the maxilla. Female skeletal profi les increase in convexity due to a tendency for the mandible to
rotate posteriorly.5
Soft-Tissue Changes
There were slight differences between males and females.
Many investigators have noted that thickness of the upper
lip in men and women decreases. Some found that the lower lip in females became thicker. Men show an increase in
profi le due to mandibular soft-tissue thickness. Increases
in all nose dimensions were noted.
Dentoalveolar Changes
Mandibular incisor movement was basically vertical, resulting from continued dental eruption, alveolar growth,
or both.
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Increase in arch width is seen until the eruption of the
permanent cuspids, after which a continued decrease in
arch width is seen over time.6,7 The intermolar width remains stable through the ages of 13 to 20. Over time, there
is a reduction of the anterior-posterior dimension of the
mandibular arch.6,8,9 Incisor irregularity increases during
the teenage years.8,10
There is a decrease in interincisor and intercanine arch
widths and total arch length during the adult stages of life.
Sinclair and Little state that the increase in incisal crowding in untreated subjects is one-third of the total amount of
crowding observed after orthodontic retention ceases.11
Carter states that the oral musculature and dental attrition are responsible for the arch decrement and the increase
in crowding.12
of mastication attach to the skull and mandible in such
a way that they deliver anterior forces to the dentition.22
Anterior occlusal forces have been demonstrated and may
be associated with post-retention crowding.23
Southard studied interproximal forces created by the
periodontium and concluded that interproximal force exists that keeps the teeth in a state of compression, creating
a contact.24 He found that occlusal loading from normal
chewing increases these forces and may explain crowding
between mandibular anterior teeth.
Akgul states that the postural changes that occur as we
age alter the pressure of the oral musculature and affect the
dental arches.4
Muscle Balance/Soft-tissue Forces/Habits
Researchers such as Strang, Weinstein, Reitan, and Mills
all believe that mandibular intercanine stability correlates
strongly with musculature.13,14,15,16 The tongue, lips, and
cheeks create a zone of equilibrium, but during orthodontic treatment teeth are moved into unstable positions. 9
Soft tissues at rest and during function alter tooth
positions based on the pressures they exert. It is well
documented that tongue position, cheek position, and the
forces created by speech, swallowing, and habits play a key
role in maintaining tooth position. For example, children
can develop constricted maxillas due to obstructed airways
(tonsils and adenoids) caused by mouth breathing, which
causes the cheek musculature to constrict the maxilla during development. Adults with similar adult open-mouth
breathing patterns exert forces on the maxillary teeth which
can alter arch form. Children with finger habits place forces
on the upper and lower incisors and premaxilla, altering
teeth positions. Patients out of orthodontic treatment may
bite their nails, chew on pens, or develop similar habits
which can also alter the positions of teeth.
Researchers have studied dental casts at varying intervals after orthodontic treatment, indicating changes that
occurred after treatment and retention. Dental changes
seen after orthodontic treatment may not be related to
relapse but rather to normal changes that occur naturally with age.25
Bishara speculates that increased mandibular crowding in adolescents treated to a well-aligned dentition can
be expected. Various amounts of crowding occur in the
anterior part of the dental arches as part of the normal
maturation process.5
Periodontium
After orthodontic treatment, reorganization of the periodontal ligament occurs over a three to four month period.
Reorganization of the gingival collagen-fiber network typically occurs over a four to six month period. Supercrestal
fibers remain deviated over seven months, applying forces
that cause rotational relapse.26 Melrose found that after
tooth movement, residual forces remain in the periodontal
tissues surrounding teeth which have recently moved.17
Occlusal Factors and Forces
Tooth stability and occlusion have long been discussed by
experts such as Angle and Okeson. It has been hypothesized and stated that an interdigitated occlusion may prevent drifting of teeth. Ideal orthodontic treatment goals
try to achieve a Class I molar and canine relationship,
with acceptable overbite and overjet. Studies have been
conducted to better understand the occlusal forces at play
that alter stability. Teeth that were once in crossbite and
retained by the occlusion are stable and seldom relapse.17
Stability of overbite reduction has been shown when the
interincisal angle is favorable.18 Beyron describes that
multidirectional chewing patterns may minimize tooth
migration.19 Dental malalignment has been associated
with an anterior component of force which may contribute to lower crowding.20,21 Okeson states that the muscles
Arch Length and Width
Intercanine and intermolar widths decrease during the
post-retention period. This is especially true if orthodontic
expansion has been done. Some of the narrowing of the
mandibular canines may be due to mesial drift as a function
of aging.1,7 Moussa showed good post-orthodontic molar
and canine widths after expansion but poor post-treatment
mandibular changes, with intercanine widths approximating the pretreatment measurements.27
De La Cruz’s ten-year post-retention study concluded
that arch forms tend to return to their original form after
expansion.28 Arch length and depth continued to decrease
over time in both arches, mainly due to changes in the arch
form. Though they were subtle, they were statistically significant.1 These changes seem to be a major cause of mandibular incisor change during the post-treatment period.29
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Changes Occurring After
Orthodontic Treatment
3
Curve of Spee
Curve of Spee was studied by Shannon, who found it to
be relatively stable after treatment.30 Varying degrees of
relapse occurred in some patients. He determined that
there were no significant differences in the degree of
Curve of Spee relapse when comparing extraction and
non-extraction cases. Increases in overbite were generally seen in patients that had had relapse. Patients with
removable retainers had significantly more relapse than
those with fixed retainers. Class II malocclusions had
deeper pretreatment Curve of Spee measurements than
did the Class I malocclusions.
Gender
Many studies have attempted to determine if relapse is more
prevalent in males or females. A study published in November 2005 indicates that males show greater facial growth
and increased instability.31 Other studies indicate there is no
significant difference between males and females.
Severity of Malocclusion
Ormiston concluded that the initial severity of the malocclusion correlates with the post-retention instability: the
more severe the initial malocclusion the greater the chance
of relapse. This is a common belief among clinicians.
Mandibular Incisor Dimensions and Position
Shields and Houston studied initial incisor position and
determined that it may be the best guide to long-term
stability.32,33 Results showed that if advancement of the
lower incisors occurs during orthodontic treatment, permanent retention is vital to maintain the results. The more
crowding present prior to treatment, the more indefinite
retention is needed.
Peck and Peck developed a ratio that described the
proper dimension of the lower incisors relative to the rest
of the dentition.34 This analysis has been used in studies
to aid researchers in determining tooth size discrepancies.
Shah concluded that no clinical predictors based on lower
incisor labial crown shape can be established for lower
crowding.35 Similarly, other studies support the idea that
tooth structure (dimension) plays a minor role, if any, in
late mandibular crowding.9,36,37,38,39,40
Wisdom Teeth
Patients frequently state that their lower crowding is due
to their wisdom teeth. However, the wisdom teeth theory
has been studied by many researchers and the consensus
is that they do not cause lower crowding. Time after time,
studies show that lower crowding still occurs in patients
who have had their wisdom teeth removed. Again, adult
crowding is most likely due to the pre-programmed mesial
drift of teeth, accentuated by occlusal forces, normal wear
of interproximal contacts, and deepening of bites.9
4
Orthodontic Treatment Plans —
Do They Make a Difference in
Post-Retention Crowding?
I have summarized the literature in an attempt to describe
the efforts of researchers who have been trying to find “better ways” to treat patients that would result in a shortening
or elimination of long-term retention.
Serial Extractions with No Appliance Therapy
Kinne discussed his analysis of 55 patients who had been
treated with serial extraction with no additional appliance
therapy, and Person studied 42 patients 20 years after
serial extraction.9 Both studies showed post-treatment irregularities that were not acceptable.
Serial Extractions with Appliance
Therapy Afterwards
Little studied post-retention patients who had undergone serial extractions followed by appliance therapy.34,41
Seventy-three percent of these patients had an unsatisfactory post-retention result with bicuspids extracted.
When compared to a matched sample of 30 patients who
had each had four bicuspids extracted, there was no difference in the relapse.
Non-Extraction Treatment with General Spacing
Little and Riedel studied 30 patients with generalized spacing of the anterior teeth prior to treatment.42 At ten years
post-retention, there was a fifty percent success rate. Mandibular space did not re-open in any case. The most commonly recurring diastemas were at the maxillary midline.
Lower Incisor Extraction
Riedel studied patients who had undergone lower incisor
extractions, including 24 patients with single-tooth extractions six and a half years post-retention, and 18 patients with
two incisors extracted almost ten years post-retention.43
Twenty-nine percent of the single-tooth extraction group
and fifty-six percent of the double-tooth extraction group
had unacceptable post-retention crowding.
Early Extractions vs. Late Extractions
McReynolds studied the records of 46 patients at least
ten years post-retention, divided into two groups.44 One
group had had early removal of mandibular second premolars during the mixed dentition, and the other had had
extractions performed when all the permanent teeth were
present. No differences in long-term stability were found
between the two groups.
Non-Extraction with Rapid Palatal
Expansion Treatment
Results for patients undergoing palatal expansion without
extraction show mixed results when looking at post-retenwww.ineedce.com
tion relapse of the lower incisors. Arch length was maintained in only a few of the patients studied by Amott.45
Moussa studied 55 patients with non-extraction and rapid
palatal expansion, and reported only an 0.8mm irregularity.27 Elms demonstrated only a 0.4mm irregularity in his
study of 42 patients.46
Haas found that by expanding the maxillary arch,
intermolar and interpremolar widths also increased (most
likely due to changes in occlusion and changes in musculature balance), buccal forces diminished, and lingual forces
increased, increasing lower arch width.47
Non-Extraction Treatment
Little reviewed records for 26 patients with a mixture
of removable and fixed appliances who had been treated
orthodontically without extraction and who received treatment in the mixed dentition.41 Results showed that eightynine percent demonstrated unsatisfactory alignment of the
lower incisors. Sadowsky showed similar results when he
studied 22 non-extraction patients who had been out of
retention for approximately five years.48
Extraction Treatment
Little demonstrated in a study of 65 treated extraction
patients ten years out of retention that the success rate of
maintaining satisfactory lower incisor alignment was less
than thirty percent, showing a mean post-retention relapse
of 2.9mm.49
Extraction vs. Non-Extraction Treatment
Many authors have compared samples of patients who
have received extraction with those who have not. Again,
there was no significant difference in the amount of lower
mandibular crowding between the two groups. Luppanapornlarp reported irregularity indices post-retention of
2.6 for the extraction group and 3.1 for the non-extraction
group.50 Artun showed irregularity indices post-retention
as 3.1 for the extraction group and 2.5 for the non-extraction group.51
Problems With Studies
Mandibular arch crowding occurs in most people who are
not actively in retention regardless of whether or not they
received orthodontic treatment. Studies themselves have
inherent problems which make it difficult to pin down
answers, such as:52
1. Variations in the methods used to measure
crowding exist.
2. Treatment ages vary among patient groups.
3. Retention times vary in subjects.
4. Not all cases studied are treated with the
same appliances.
5. Different practitioners are treating the
patients studied.
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6. Different angle classifications exist in patient groups.
7. Different types of mechanics are being employed to
straighten teeth.
What Is Being Taught to Orthodontists to
Help Prevent Relapse?
The orthodontic specialty has devoted many hours researching the prevention of relapse based on the hundreds
of papers published. Graber and Vanarsdall postulated the
following theorems pertaining to orthodontic treatment and
relapse.53 Keep in mind that this list represents ideals and
may or may not actually help prevent relapse indefinitely.
1. Teeth that have been moved tend to return to their
former positions.
2. Elimination of the cause of malocclusion will
prevent recurrence.
3. Malocclusion should be overcorrected as a
safety factor.
4. Proper occlusion is a potent factor in holding teeth in
their corrected positions.
5. Bone and adjacent tissues must be allowed to reorganize around newly positioned teeth.
6. If the lower incisors are placed upright over
basal bone, they are more likely to remain in
good alignment.
7. Corrections carried out during periods of growth are
less likely to relapse.
8. The further teeth have been moved, the lower the
likelihood of relapse.
9. Arch form, particularly in the mandibular arch,
cannot be permanently altered by appliance therapy.
Post-Orthodontic Procedures to Help
Prevent Relapse
Circumferential Supracrestal Fiberotomy (CSF) is one of
the few successful post-orthodontic treatments to show any
long-term success in preventing rotational relapse. CSF is
performed immediately after removal of the orthodontic
appliance. By releasing the soft-tissue tension and allowing
the reattachment of periodontal fibers, moderate long-term
success has been shown in preventing rotational relapses.
This treatment has been well studied. After CSF, little or
no attachment loss has been described of any significance,
nor any other negative sequelae. It is recommended that
patients with moderate to severe pre-orthodontic rotations
in the lower anteriors undergo CSF.
Discussion
Post-orthodontic retention is needed to allow for periodontal and gingival reorganization, to minimize changes
of growth, to permit neuromuscular changes and adaptation to the new tooth positions, and to maintain unstable
tooth positions which may have been established to meet
treatment goals and esthetic considerations.9
5
Orthodontic stability begins with the mandibular arch,
especially the mandibular anterior teeth. The maxillary
arch wraps around the mandibular arch, and changes that
occur in the upper arch follow the lower teeth.52
Nanda discussed retention concerns in young patients
undergoing puberty or in some stage of active growth.54
He stated that different retention devices based on facial
morphology and severity of the malocclusion should be
considered. For example, Class II individuals who may
still need upper retraction force to prevent the maxilla
from continuing to grow forward when the mandible has
stopped growing. Patients with short face syndrome may
need bite-plate type retainers until maxillomandibular
growth is completed. Conversely, patients who have long
face syndrome may require a high-pull face bow headgear
to hold the position of the molars and to prevent further
downward and backward growth of the mandible.
Indefinite retention is the only solution we have today to
keep teeth aligned over time. It is hard to argue the fact that
without indefinite retention the dental arches will change,
starting with the lower anterior teeth. In many individuals,
these changes will result in varying degrees of collapse of
the dental arches. Discussing orthodontic retention with
patients should be no different than discussing brushing
and flossing regimens. Preventing relapse is possible. I
recommend the following:
1. Dentists, hygienists, and orthodontists need to
inform patients that retention should be indefinite
regardless of the pre-existing malocclusion, the
treatment modality, or length of time they were in
treatment. Since we have no way of determining who
will develop lower crowding relapse, the retainer will
act as insurance indefinitely.
2. Dental practitioners need to incorporate a statement
regarding indefinite retention into their pretreatment
informed consent documents and remind patients
at the end of orthodontic treatment that indefinite
retention is a must.
3. Dental practitioners need to develop a regular
post-orthodontic retention program. Fee structures
need to be developed to accommodate retention needs,
including a retainer exam fee, a retainer adjustment
fee, a retainer replacement fee, and, if needed, limited
re-treatment fees.
4. Practitioners need to perform “retention relapse
examinations” similar to providing their patients with
an oral cancer screening. This is easily done at the
regularly scheduled prophy exam. The exam can begin
with some simple questions:
a. Have you had orthodontic treatment?
b. Do you wear retainers?
c. Do you see your orthodontist to have
them adjusted?
d. Do you know that indefinite retention is necessary?
6
An oral examination needs to be performed to
evaluate the dentition for relapse, beginning with
the lower incisors.
5. Dental professionals need to offer retainers to their
patients, regardless of whether patients have had
braces or not. If patients need bruxing appliances,
combination splint-retainers can be fabricated for the
lower jaw.
Summary
Many studies have been performed to ascertain if there
is a better way to move teeth that will reduce post-orthodontic relapse. Relapse happens, and it may have very
little to do with the treatment mechanics or plan. Despite
recommended measures to decrease the chances of relapse, nothing definitive has been developed. Permanent
retention is the only reliable way to keep the dental arches
in a position similar to the position they were in the day
after the patient’s braces were removed. Prevention of
dental relapse is possible if an interdisciplinary approach
is developed.
Patients come into our offices trusting that we will give
them a straight smile. They spend thousands of dollars and
years of their lives awaiting straight teeth. We make them
retainers, tell them to wear them, and send them on their
way. The majority of these patients eventually discontinue
wearing their retainers.
Orthodontic practices in this country are not geared to
track patients for more than a year or two after treatment.
The majority of these practices are efficient at treating patients and getting them into retention but do not continue
to monitor them over their lifetime. The responsibility for
evaluating a patient’s post-orthodontic occlusion rests in
the hands of the dentists and the hygienists who will care
for them for the rest of their lives. The orthodontist is not
in this chain of professionals until a problem returns, and
the patient is being referred back for re-treatment. Most
orthodontic patients graduate high school, move away to
college, and lose touch with their orthodontist. The general dental practice is the only line of defense that exists
to spread the message and provide the retention services
needed indefinitely.
The general dentist needs to take advantage of this
opportunity to not only provide patients with an invaluable service but to establish a new income stream for the
practice. We have committed our lives to the practice of
dentistry and the principles of ethics, which were founded
on the basis of nonmaleficence. We counsel our patients on
brushing, flossing, smoking cessation, effects of tobacco
and oral cancer, bruxing, and sleep disorders. We all must
continue the campaign on educating our peers and patients
on the importance of retention. I hope this article will be
a catalyst for all dentists and hygienists as our profession
continues to evolve.
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incisor alignment many years after orthodontic therapy. Am J
Orthod. 1984;86(4):299–305.
39 Glenn G, Sinclair PM, Alexander RG. Nonextraction orthodontic
therapy: posttreatment dental and skeletal stability. Am J Orthod
Dentofacial Orthop. 1987;92(4):321–328.
40 Little RM. The irregularity index: a quantitative score of mandibular
anterior alignment. Am J Orthod. 1975;68(5):554–563.
41 Little RM, Riedel RA, Stein A. Mandibular arch length increase
during the mixed dentition: postretention evaluation of stability and
relapse. Am J Orthod Dentofacial Orthop. 1990;97(5):393–404.
42 Little RM, Riedel RA. Postretention evaluation of stability and
relapse — mandibular arches with generalized spacing. Am J
Orthod Dentofacial Orthop. 1989;95(1):37–41.
43 Riedel RA, Little RM, Bui TD. Mandibular incisor extraction
— postretention evaluation of stability and relapse. Angle Orthod.
1992;62(2):103–116.
44 McReynolds DC, Little RM. Mandibular second premolar
extraction — postretention evaluation of stability and relapse.
Angle Orthod. 1991;61(2):133–144.
45 Amott RD. A serial study of dental arch measurements on
orthodontic subjects: 55 cases at least 4 years postretention [MSD
Thesis]. Chicago: Northwestern University Dental School. 1962.
46 Elms TN, Buschang PH, Alexander RG. Long-term stability of Class
II, Division 1, nonextraction cervical face-bow therapy: I. Model
analysis. Am J Orthod Dentofacial Orthop. 1996;109(3):271–276.
47 Haas AJ. Long-term posttreatment evaluation of rapid palatal
expansion. Angle Orthod. 1980;50(3):189–217.
48 Sadowsky C, Schneider BJ, BeGole EA, Tahir E. Long-term
stability after orthodontic treatment: nonextraction with prolonged
retention. Am J Orthod Dentofacial Orthop. 1994;106(3):243–249.
49 Little RM, Wallen TR, Riedel RA. Stability and relapse of
mandibular anterior alignment-first premolar extraction cases
treated by traditional edgewise orthodontics. Am J Orthod.
1981;80(4):349–365.
50 Luppanapornlarp S, Johnston Jr LE. The effects of premolar
extraction: a long-term comparison of outcomes in “clear-cut”
extraction and nonextraction Class II patients. Angle Orthod.
1993;63(4):257–272.
51 Artun J, Garol JD, Little RM. Long-term stability of mandibular
incisors following successful treatment of Class II, Division 1,
malocclusions. Angle Orthod. 1996;66(3):229–238.
52 Shah AA. Postretention changes in mandibular crowding: a
review of the literature. Am J Orthod Dentofacial Orthop.
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2003;124(3):298–308.
53 Graber TM, Vanarsdall RL. Orthodontics. Current Principles and
Techniques. St. Louis: Mosby. 2002;34:1012.
54 Nanda RS, Nanda SK. Considerations of dentofacial growth in
long-term retention and stability: is active retention needed? Am J
Orthod Dentofacial Orthop. 1992;101(4):297–302.
Author Profiles
Michael Florman, DDS
Dr. Florman received his dental
degree from the Ohio State University and completed his post graduate
training in Orthodontics at New
York University. Dr. Florman is a
Diplomate of the American Board of
Orthodontics, and has been practicing dentistry since 1991. He is highly
respected as both an orthodontist and an educator. He has
authored over forty scientific publications in the field of
dentistry and medicine. Dr. Florman is an active clinical
advisor to many pharmaceutical and dental companies. He
is a member of the American Dental Association, California Dental Association, and the American Association of
8
Orthodontists. His hobbies include golf, running, hiking,
bicycling, photography, and computer graphic design.
Mahtab Partovi, DDS
Dr. Partovi received her dental degree
from New York University College of
Dentistry. Dr. Partovi is presently
managing two clinical orthodontic
studies and plans on pursuing a specialty degree in the field of orthodontics in the near future. She is a member
of the American Dental Association
and the California Dental Association.
Disclaimer
The authors of this course have no commercial ties with the
sponsors or the providers of the unrestricted educational
grant for this course.
Reader Feedback
We encourage your comments on this or any PennWell course.
For your convenience, an online feedback form is available at
www.ineedce.com.
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Questions
1. At what ages do girls mature with
skeletal patterns similar to women?
a. 9–10
b. 11–13
c. 13–15
d. 15–17
2. Which is not corect about latent
mandibular growth?
a. It causes sagital discrepancies
b. It results in lower jaw overgrowth
c. It can occur in boys into their twenties
d. It usually occurs in girls
3. As people age, lower facial height
increases due to:
a. Lower anterior teeth tipping forward
b. Continued eruption of teeth
c. Lower crowding of anterior teeth
d. All of the above
4. As we age, investigators have
found that:
a. All dimensions of the nose increase
b. Men show increases in mandibular profiles
c. Thickness of upper lips decreases
d. All of the above
5. Arch width increases in growing
children until the eruption of:
a. Permanent central incisors
b. Permanent lateral incisors
c. Permanent canines
d. Permanent first molar
6. The increase in incisal crowding in
untreated subjects is what fraction of the
total amount of crowding observed after
orthodontic retention.
a. One fifth
b. One quarter
c. One third
d. One half
7. It is believed that which muscle(s) create a zone of equilibrium keeping teeth
in their position?
a. Tongue
b. Cheek
c. Lip
d. All of the above
8. Due to the muscles of mastication, there
are mesial directed forces on the teeth.
Multidirectional chewing patterns have
nothing to do with tooth migration.
a. 1st statement is true. 2nd statement is true.
b. 1st statement is true. 2nd statement is false.
c. 1st statement is false. 2nd statement is true.
d. 1st statement is false. 2nd statement is false.
9. Interproximal forces keep teeth in
a state of compression and contact.
Occlusal loading may explain crowding
between lower teeth.
a. 1st statement is true. 2nd statement is true.
b. 1st statement is true. 2nd statement is false.
c. 1st statement is false. 2nd statement is true.
d. 1st statement is false. 2nd statement is false.
10. Supercrestal fibers remain deviated
for up to how many months after
orthodontic treatment?
a. 1
b. 3
c. 5
d. 7
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11. Arch length and depth continue to
decrease over time:
a. In the maxillary arch only
b. In the mandibular arch only
c. In both arches
d. None of the above
12. The curve of Spee was relatively stable
after orthodontic treatment. There were
differences between extraction groups
vs. non extraction groups.
a. 1st statement is true. 2nd statement is true.
b. 1st statement is true. 2nd statement is false.
c. 1st statement is false. 2nd statement is true.
d. 1st statement is false. 2nd statement is false.
13. A recent study demonstrated that
males show greater facial growth and
increased instability after treatment.
a. True
b. False
14. Relapse is not associated with the
severity of the original malocclusion.
a. True
b. False
15. If advancement of the lower incisors
occurs during treatment, there is more
need for permanent retention.
a. True
b. False
16. Tooth shape and size discrepancies
play a large role in mandibular
crowding prediction.
a. True
b. False
17. Wisdom teeth removal will
prevent lower incisor crowding
after orthodontic treatment.
a. True
b. False
18. Serial extractions with appliance
therapy compared to patients with
four bicuspids extracted showed no
difference in relapse.
a. True
b. False
19. What percent of patients studied had
spacing relapsed?
a. 20
b. 30
c. 40
d. 50
20. In patients treated who had spacing
initially, where was the most common
relapse area?
a. Mandibular midline
b. Distal to premolars
c. Maxillary midline
d. None of the above
21. In the lower incisor extraction
studies, what percent of the single tooth
extraction group and the double tooth
extraction group showed unacceptable
post-retention crowding?
a. 30, 76
b. 76, 30
c. 56, 29
d. 29, 56
22. In the non-extraction studies, what
percent of the treated cases showed
unsatisfactory alignment of the
lower incisors?
a. 98
b. 89
c. 76
d. 45
23. In a study of extraction patients, what
percent of patients maintained satisfactory lower incisor alignment 10 years
out of retention.
a. 20
b. 30
c. 40
d. 50
24. There were no differences between
the extraction groups studied and the
non-extraction groups.
a. True
b. False
25. Which is not a problem associated with
the studies in this article.
a. Treatment ages were not uniform
b. Different clinicians treated the patients
c. Retention times varied between patients
d. None of the above
26. It is taught: Teeth that have moved
tend to return to their former positions.
Corrections carried out during periods
of growth are likely to relapse.
a. 1st statement is true. 2nd statement is true.
b. 1st statement is true. 2nd statement is false.
c. 1st statement is false. 2nd statement is true.
d. 1st statement is false. 2nd statement is false.
27. It is taught: The mandibular arch form
can be permanently altered by appliance
therapy. Proper occlusion holds the
teeth in their positions.
a. 1st statement is true. 2nd statement is true.
b. 1st statement is true. 2nd statement is false.
c. 1st statement is false. 2nd statement is true.
d. 1st statement is false. 2nd statement is false.
28. CSF has not proven to be very valuable
in preventing post-retention relapse.
a. True
b. False
29. Orthodontic stability begins with
the mandibular anterior teeth. The
maxillary teeth are held in position by
the mandibular teeth.
a. 1st statement is true. 2nd statement is true.
b. 1st statement is true. 2nd statement is false.
c. 1st statement is false. 2nd statement is true.
d. 1st statement is false. 2nd statement is false.
30. Which is not true?
a. Dentists and hygienists should be incorporating
retention examinations into their practice.
b. The orthodontist does a poor job in following up
with patients years after treatment.
c. Dentists should offer patients retainers services
as part of a long term commitment to their
dental health.
d. None of the above.
9
ANSWER SHEET
Indefinite Orthodontic Retention
Name:
Title:
Address:
E-mail:
City:
State:
Telephone: Home (
)
Office (
Specialty:
ZIP:
)
Requirements for successful completion of the course and to obtain dental continuing education credits: 1) Read the entire course. 2) Complete all
information above. 3) Complete answer sheets in either pen or pencil. 4) Mark only one answer for each question. 5) A score of 70% on this test will earn
you 4 CE credits. 6) Complete the Course Evaluation below. 7) Make check payable to PennWell Corp.
Mail completed answer sheet to
Educational Objectives
Academy of Dental Therapeutics and Stomatology,
1. Describe orthodontic relapse in detail and understand how and why it occurs
A Division of PennWell Corp.
2. Discuss normal growth and development as it pertains to orthodontic relapse
3.Explain how the normal occlusal factors, muscle function, and soft-tissue forces keep teeth in their normal positions as
well as move teeth out of position
4.Understand the changes that occur after orthodontic treatment, allowing the reader to grasp the importance of
indefinite retention
5.Assess the proper solutions to orthodontic relapses and understand ideas on how all dentists can help their patients
prevent orthodontic relapse
6. Implement an orthodontic retention program
7. Create an income source while providing an invaluable service to patients
P.O. Box 116, Chesterland, OH 44026
or fax to: (440) 845-3447
For immediate results, go to www.ineedce.com
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Exp. Date: _____________________
1. Were the individual course objectives met?Objective #1:
Objective #2:
Objective #3:
Objective #4:
Yes
Yes
Yes
Yes
No
No
No
No
2. To what extent were the course objectives accomplished overall?
5
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2
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3. Please rate your personal mastery of the course objectives.
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4. How would you rate the objectives and educational methods?
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5. How do you rate the author’s grasp of the topic?
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7. Was the overall administration of the course effective?
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Objective #5: Yes No
Objective #6: Yes No
Objective #7: Yes No
8. Do you feel that the references were adequate?
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Charges on your statement will show up as PennWell
10. If any of the continuing education questions were unclear or ambiguous, please list them.
___________________________________________________________________
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___________________________________________________________________
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AGD Code 370
PLEASE PHOTOCOPY ANSWER SHEET FOR ADDITIONAL PARTICIPANTS.
AUTHOR DISCLAIMER
The authors of this course have no commercial ties with the sponsors or the providers of
the unrestricted educational grant for this course.
SPONSOR/PROVIDER
This course was made possible through an unrestricted educational grant. No
manufacturer or third party has had any input into the development of course content.
All content has been derived from references listed, and or the opinions of clinicians.
Please direct all questions pertaining to PennWell or the administration of this course to
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survey included with the course. Please e-mail all questions to: [email protected].
10
INSTRUCTIONS
All questions should have only one answer. Grading of this examination is done
manually. Participants will receive confirmation of passing by receipt of a verification
form. Verification forms will be mailed within two weeks after taking an examination.
EDUCATIONAL DISCLAIMER
The opinions of efficacy or perceived value of any products or companies mentioned
in this course and expressed herein are those of the author(s) of the course and do not
necessarily reflect those of PennWell.
Completing a single continuing education course does not provide enough information
to give the participant the feeling that s/he is an expert in the field related to the course
topic. It is a combination of many educational courses and clinical experience that
allows the participant to develop skills and expertise.
COURSE CREDITS/COST
All participants scoring at least 70% (answering 21 or more questions correctly) on the
examination will receive a verification form verifying 4 CE credits. The formal continuing
education program of this sponsor is accepted by the AGD for Fellowship/Mastership
credit. Please contact PennWell for current term of acceptance. Participants are urged to
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