Download Restorative space management: Treatment planning and clinical

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C O N T I N U I N G
E D U C A T I O N
X X
RESTORATIVE SPACE MANAGEMENT:
TREATMENT PLANNING AND CLINICAL
CONSIDERATIONS FOR INSUFFICIENT SPACE
KIM
Jason Kim, CDT, MDT* • Stephen Chu, DMD, MSD, CDT, MDT† • Galip Gürel, DDS‡ • George Cisneros, DMDII
JANUARY/FEBRUARY
17
1
In attempting to provide a restorative solution for cases that have been compromised by spatial considerations, clinicians have traditionally opted for an orthodontic approach that did not provide optimal aesthetics due to changes in tooth
morphology, specifically tooth size and shape as a result of dental deterioration.
With the advent of contemporary aesthetic materials and preparation techniques,
clinicians and technicians are now empowered to deliver a penultimate result with
minimal compromise to the surrounding dentition. This article presents the clinical
and laboratory considerations that must be addressed when providing a prosthetic
restoration for crowded teeth.
Learning Objectives:
This article discusses an option outside of orthodontics in the restoration of cases
that are compromised by spatial considerations. Upon reading this article, the
reader should:
• Be able to address the clinical factors needed with spatially
compromised cases.
• Understand laboratory considerations in the restoration of such cases.
Key Words: orthodontic, aesthetic, space, tooth proportion
* Master dental technician, Jason J. Kim Dental Laboratories/International Oral Design,
New York, NY.
† Clinical Associate Professor and Director, Advanced and International Programs in
Aesthetic Dentistry, Department of Implant Dentistry, New York University College of
Dentistry, New York, NY; private practice, New York, NY.
‡ Private practice, Istanbul, Turkey.
II Professor and Chairperson, Department of Orthodontics, New York University College of
Dentistry, New York, NY.
Stephen J. Chu, DMD, MSD, CDT, MDT, 205 East 64th Street, Ste. 502, New York, NY 10021
Tel: 212-980-9310 • Fax: 212-980-9647 • E-mail: [email protected]
Pract Proced Aesthet Dent 2005;17(1):A-X
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Practical Procedures & AESTHETIC DENTISTRY
O
rthodontic therapy represents an excellent, predictable
means of achieving tooth movement to address aes-
thetic and functional concerns. Most patients can benefit
functionally and aesthetically from orthodontic therapy. This
is particularly true in patients who present with a crowded
smile (dentition), commonly marked by overlapping and
misaligned teeth. The benefits of orthodontic therapy from
a periodontal, restorative, and cosmetic point of view are
well-documented.1 Periodontal defects can be reduced,
and restoratively compromised teeth can be salvaged
through orthodontic forced eruption.2 This technique is used
to correct cosmetic midfacial soft tissue discrepancies in
Figure 2. Appearance of the mandibular arch prior to preparation.
Note the misaligned teeth.
the gingival architecture.3 It enhances aesthetics by reestablishing proper tooth proportions and altering the location
of the midfacial and interproximal gingival tissues, often
called the interdental papilla.
Innovative materials (eg, temperature-sensitive/
activated archwires, ceramic brackets), combined with
new techniques in contemporary orthodontic therapy, have
led to the development of aesthetic and efficient treatment
devices as well as streamlined treatment times. These
developments have given rise to a greater level of acceptance of orthodontics in the adult patient population.
Even with these advances in treatment, some patients
may refuse orthodontic therapy due to occupational
limitations of time and appearance during treatment. The
development and introduction of removable, acrylic-based
Figure 3. On the preoperative stone model, red lines indicate the ideal
arch restored position, and blue lines indicate required reduction.
orthodontic aligners has increased patient acceptance,
particularly those resistant to fixed appliances. Although
treatment with aligning appliances has many benefits, there
are limitations as well. In addition, some questions have
been raised with respect to stability of treatment outcomes,
specifically, long-term retention of rotational corrections present in the crowded dentition postoperatively.4 The potential for orthodontic relapse has inspired the use of tooth
preparation and restorative dentistry to recreate tooth dimensions and proportions commensurate with postorthodontic results from both an aesthetic and functional clinical
Figure 1. Preoperative appearance of the patient who presented for
treatment of severe overcrowding.
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outcome, thereby eliminating the potential for relapse and
the need for forced orthodontic tooth movement.5
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Kim
dentist performs reconstructive dentistry by tooth restoration. The quantity of tooth structure removed must be
defined and limitations established to avoid subsequent
problems associated with overly aggressive removal of
uncompromised tooth structure.
Biologic and Structural Parameters
The parameters for RSM are defined by the dimensions
and structures of the teeth and surrounding periodontium within the dental arches. There are limits to the
degree of tooth structure that can be removed before pulFigure 4. Mesiodistal overlaps (marked with blue) will require reduction necessary to allow subsequent expansion of the arch form.
pal and periodontal violation result. Since the pulpal
chamber size decreases with age, this parameter is influenced by the individual characteristics of each case and
the age of the patient. Excessive tooth removal to accomplish the goals of therapy may require mutilation of the
remaining tooth structure, thus compromising the biologic
and structural outcomes from three essential aspects:
endodontic instability regarding questionable pulpal
health and long-term prognosis of root canal treatment;
structural instability of the remaining tooth structure to support the restoration and/or occlusal scheme; and periodontal instability caused by resultant changes in
restorative tooth morphology (eg, unfavorable proximal
contours that could impede proper oral hygiene and
Figure 5. Approximately 2 mm of buccolingual overlap was evident
and a mesiodistal overlap of less than 1 mm was also observed.
encourage food impaction and plaque retention). One
must consider the aforementioned guarded consequences
Restorative Space Management (RSM) is defined
as therapy that uses tooth preparation techniques and
designs to accomplish the goals of orthodontic therapy.
It requires selective and strategic removal of tooth structure and the addition of cosmetic restorative materials
(eg, direct/indirect restorations). Unlike traditional orthodontic therapy, the benefits of RSM include correction
of tooth shapes and dimensions that improve tooth proportions, as well as color correction, concomitantly.
The goals of therapy for the orthodontist and restorative dentist are similar; how they achieve the results is
the only difference. The orthodontist achieves his or her
Figure 6. The necessary buccal and lingual parameters were modified to facilitate development of an ideal arch form.
goals through tooth movement, while the restorative
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Figure 7. A mock-up was created to visualize the anticipated postoperative tooth form.
Figure 8. Incisal index of the mock-up. Pencil lines indicate proper
spatial relationship and width of teeth at the incisal aspect.
afforded by such therapy without regard for the aesthetic
Space is frequently gained by preparing the pos-
and functional effects. In addition, negative gingival and
terior teeth in ways that require removal from the mesial
interdental papilla architecture cannot be remediated
aspect and addition to the distal aspect. Moderate
through RSM treatment.
crowding can often be successfully treated using this technique. An average of 1 mm to 1.5 mm of total reduc-
Treatment Planning
tion per tooth can be comfortably obtained due to the
Tooth crowding can pose an intellectual and techni-
interproximal contours of teeth and the anatomy of avail-
cal challenge, since both mesiodistal and buccolin-
able enamel.8 When multiplied by the number of teeth
gual discrepancies must be addressed. Resultant
involved, the result should give adequate space to realign
periodontal instability can be more of a contraindi-
the crowded dentition.
cation in these cases. The objectives of RSM therapy
Buccolingual changes in tooth position can be asso-
in a case with insufficient space are to restore proper
ciated with discrepancies in gingival architecture (eg,
tooth proportions and establish a stable physiologic
midfacial tissue height, papilla height, papilla shape)
occlusion. Ward identified the “recurring esthetic
that require adjunctive periodontal therapy or orthodon-
dental” or RED proportion, which is the width-to-length
tic correction. Mild-to-moderate discrepancies, such as
proportion of the maxillary teeth that falls between
Class I and Class II case types, are easily and predictably
75% and 80%.6 Invariably, this requires the creation
treated by RSM. Severe case types, such as Class IV,
of space to straighten the anterior dentition. The
could require tooth mutilation as well as significant peri-
resultant “Tooth Proportion” formula is as follows:
odontal therapy (ie, crown lengthening), which would
Tooth Proportion = Width divided by Length, which
be a contraindication to RSM treatment.
should fall in the 75% to 85% range, in order to
Class III case types frequently require adjunctive
be considered aesthetic. In such instances, the
orthodontic and/or periodontal therapies and may
clinician must assess where the necessary space can
require elective endodontics in borderline cases in order
be gained to accomplish the treatment objectives
to correct the functional and aesthetic deficiencies.
by reducing existing structures rather than shifting the
Class IV case types cannot and should not be treated
dentition orthodontically.
without orthodontic and periodontal consideration (Table).
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Table
Gingival Considerations Based on Defect Classification
Category
Amount of Overlap
Papilla Height
Discrepancy
Papilla Shape
Distortion
Adjunctive Therapy
Symmetrical
Not Visible
None
Class I
MD < 1 mm
BL < 1 mm
Class II
MD < 1 mm - 2 mm
BL < 1 mm
< 1mm
Not Visible
None
Class III
MD < 1 mm - 2 mm
BL < 1 mm - 2 mm
1.5 mm - 2 mm
Moderate
Consider Periodontal,
Orthodontic, and/or
Endodontic
Class IV
MD < 2.5 mm
BL < 2 mm
> 2 mm
Severe
Recommended Orthodontic/
Consider Periodontal
Space Management Case Classification
that required reduction were marked in blue, and red
Patients who present with insufficient space and resultant
lines were drawn on the incisal edges to indicate the
crowding most often require treatment in the mesiodistal
ideal restored arch position (form). The free gingival
(MD) and buccolingual (BL) direction. Classification is
tissue height was also marked to ensure development of
categorized into the amount of overlap, as well as papilla
the correct gingival architecture.
height and shape (Table). Since papilla height discrep-
One of the most significant problems when treating
ancy is slight in Class I and Class II case types, and
the insufficient (crowded) case type is creating natural-
papilla shape distortion is not visible, no adjunctive ther-
looking gingival architecture. The facially positioned teeth
apy is necessary. However, Class III case types frequently
present a thin alveolar crest with relatively thin gingival
require adjunctive orthodontic and/or periodontal ther-
tissue (that is generally positioned apically). It was eas-
apies and may require elective endodontics in border-
ier and more predictable to move the soft tissues apically
line cases to correct functional and aesthetic deficiencies.
than to bring them towards a coronal direction.
Class IV case types cannot and should not be treated
Conversely, if the teeth had been positioned too far lin-
without orthodontic and periodontal consideration.
gually, as commonly found with an overgrowth of gingival tissue towards the coronal direction, distorted
Clinical Procedures for Crowding
gingival symmetry would have been observed. In the
A 55-year-old male patient presented with moderate-to-
majority of these cases, simple gingivectomy would be
severe misalignment of teeth #22(33) through #27(43),
necessary in order to achieve correct gingival form.
along with a preexisting porcelain-fused-to-metal (PFM)
The mesiodistal overlaps were marked with blue
restoration on tooth #8(11) (Figures 1 and 2). While
vertical lines to ensure proper reduction in order to allow
teeth #23(32) and #25(41) were positioned facially,
subsequent expansion of the restored dental arch (Figure
teeth #24(31) and #26(42) were lingually retroclined
4). A buccolingual overlap of approximately 2 mm was
and created an uneven overlapping appearance. The
evident from one incisal edge to the other (Figure 5).
mandibular arch was evaluated in order to ensure devel-
A mesiodistal overlap of less than 1 mm was also evi-
opment of proper incisal contours. Following impression
dent. This borderline Class II/Class III case demonstrated
capture, a stone cast was fabricated (Figure 3). Areas
some visible distortion in the free gingival height.
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Removal of the mesial and distal interproximal areas of
the labially positioned tooth was indicated in order to
create sufficient space needed to shift the lingually positioned tooth facially.
It was critical for the clinicians to decide where
to place the facial surface so that a pleasing arch
form would be developed. Once the functional waxup
was created, an accurate diagnostic waxup was used
as the basis for the preparation guide. A red line was
drawn on the incisal edge of tooth #23 to indicate
the position of the ideal arch form (Figure 5).
Using a finishing bur, the laboratory technician cre-
Figure 9. The facially positioned teeth were prepared on the stone
model using the incisal index as a guide.
ated an arch-form preparation guide by preparing each
tooth buccally and lingually on the stone model to develop
an ideal arch form (Figure 6). This arch-form preparation
was given to the clinician as a reference during the clinical tooth preparation phase. A mock-up was then created to allow visualization of the anticipated tooth form
(Figure 7). Using condensation silicone putty, an incisal
index of the mock-up was made (Figure 8). Pencil lines
were drawn on the index to indicate proper spatial relationship as well as width of teeth at the incisal edge.
A depth bur was then used in the laboratory to
reduce the labially positioned teeth according to the
information provided by the incisal index (Figures 9 and
10). The labial index was used by the dentist as a ref-
Figure 10. Incisal view of the completed laboratory preparation
guide. Note the presence of suggested finishing-line placement.
erence guide during tooth reduction and preparation.
This guide was also used to indicate the correct final
position and help in visualizing the final dimensions of
each tooth (Figure 11). Minimal preparation was
required on the facial surface to ensure that the lost
labial volume would be filled with the porcelain laminate veneer. In order to prevent development of a thick
incisal surface, the incisal edge was trimmed lingually.
Care was taken to avoid excess reduction and subsequent modification of the finishing line to maintain substantial support for the ceramic material.
Once the tooth preparation was completed, an
impression was made and sent to the laboratory. A stone
model of this impression was poured and checked against
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Figure 11. Tooth preparation was initiated according to the predetermined parameters communicated by the labial index.
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the incisal index to verify the accuracy of the preparation
(Figure 12). The incisal index was used in the laboratory
to allow the technician to develop an optimal ceramic
buildup (Figure 13). The restorations were fired and characterized as necessary, and the finished restorations were
then sent to the dentist for definitive cementation. The definitive restorations were cemented using a composite resin
adhesive and cement (Figures 14 and 15).
Conclusion
RSM is a predictable treatment for many aesthetic and
Figure 12. The incisal index was used to help achieve optimal
ceramic buildup.
functional dental problems. A classification of treatment
guidelines is presented as a clinical means to recommend various treatment modalities to ensure aesthetic
and restorative success.
The RSM case presented herein has replicated the
treatment outcomes of orthodontic therapy through the
use of aesthetic and restorative techniques. The benefits
include correction of tooth shapes and dimensions that
result in improved tooth proportions with an aesthetically pleasing appearance. The occlusal relationship has
also been remedied to ensure a stable occlusion and
proper masticatory function.
Figure 13. Care was taken to ensure development of optimal space
management during final restoration.
Acknowledgement
The authors mention their gratitude to Dr. Marc
Lowenberg, New York, NY, for his contributions to the
clinical case shown herein.
References
Figure 14. Postoperative appearance of the definitive ceramic
restorations following delivery.
1. Brown IS. The effect of orthodontic therapy on certain types of
periodontal defects. I. Clinical findings. J Periodontol
1973;44(12):742-756.
2. Ingber JS. Forced eruption: Part II. A method of treating nonrestorable teeth—Periodontal and restorative considerations.
J Periodontol 1976;47(4):203-216.
3. Ingber JS. Forced eruption: Alteration of soft tissue cosmetic deformities. Int J Periodont Rest Dent 1989;9(6):416-425.
4. Riedel RA. A review of the retention problem. Angle Orthod
1960;30:179-199.
5. Gürel G. Predictable, precise, and repeatable tooth preparation for porcelain laminate veneers. Pract Proced Aesthet Dent
2003;15(1):17-24.
6. Ward DH. Proportional smile design using the recurring esthetic
dental proportion. Dent Clin North Am 2001;45(1):143-154.
7. Ferrari M, Patroni S, Balleri P. Measurement of enamel thickness in relation to reduction for etched laminate veneers.
Int J Periodont Rest Dent 1992;12(5):407-413.
8. Preston JD. The golden proportion revisited. J Esthet Dent
1993;5(6):247-251.
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CONTINUING EDUCATION
(CE) EXERCISE NO. X
CE
X
CONTINUING EDUCATION
To submit your CE Exercise answers, please use the answer sheet found within the CE Editorial Section of this issue and
complete as follows: 1) Identify the article; 2) Place an X in the appropriate box for each question of each exercise; 3) Clip
answer sheet from the page and mail it to the CE Department at Montage Media Corporation. For further instructions,
please refer to the CE Editorial Section.
The 10 multiple-choice questions for this Continuing Education (CE) exercise are based on the article, “Restorative space
management: Treatment planning and clinical considerations” by Jason Kim, CDT, MDT, Stephen Chu, DMD, MSD, CDT,
MDT, and Galip Gürel, DDS. This article is on pages 000-000.
1. Restorative space management (RSM) alone can
be predictably performed in:
a. Only Class I case types.
b. Only Class II case types.
c. Both Class I and Class II case types.
d. Neither Class I nor Class II case types.
2. RSM therapy alone can be predictably performed in type III and IV case types. RSM type
IV cases can be treated as Class I or Class II
postorthodontic treatment.
a. The first statement is true, the second statement
is false.
b. The first statement is false, the second statement is true.
c. Both statements are true.
d. Both statements are false.
3. Class III case types should consider what type
of adjunctive therapy?
a. Periodontal.
b. Orthodontics.
c. Endodontic.
d. All of the above.
4. Class IV case types always require:
a. Orthodontic therapy.
b. Periodontal therapy.
c. Endodontic therapy.
d. None of the above.
5. Adjunctive orthodontics is a predictable way to
alter ____ soft tissue profiles.
a. Midfacial.
b. Interproximal.
c. Both a and b.
d. Neither a nor b.
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6. RSM can be predictably accomplished without
case planning. RSM can be predictably accomplished without a clinically applicable
diagnostic waxup.
a. The first statement is true, the second statement
is false.
b. The first statement is false, the second statement is true.
c. Both statements are true.
d. Both statements are false.
7. A diagnostic waxup with associated preparation guides is recommended in which case
types?
a. Class I and Class II.
b. Class III and Class IV.
c. Class I, Class II, and Class III.
d. Class I, Class II, Class III, and Class IV.
8. This case type could require tooth mutilation, as
well as significant periodontal therapy.
a. Class I.
b. Class II.
c. Class III.
d. Class IV.
9. Golden proportion is the ratio between:
a. Central and lateral incisors.
b. Canines and the first premolar.
c. The first and second premolars.
d. All of the above.
10. Tooth proportion is defined as:
a. Width divided by length.
b. Length divided by width.
c. Width plus length.
d. Length minus width.
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