Written by Arthur R. Volker, DDS, MSEd, and David Clark, DDS Thursday, 08 December 2011 15:35
The following case describes the use of prerestorative orthodontic care, Bolton Analysis, Golden Proportion analysis, tooth whitening, and a simplified and minimally invasive restorative protocol to achieve a predictable, systematic, and aesthetic smile enhancement.
Diagnosis and Treatment Planning
A 25-year-old male presented to the practice with a chief complaint of, "I want the space between my front teeth closed." There was a 5-mm diastema present between teeth Nos. 8 and 9 (Figure 1). The patient stated that he was interested in Invisalign (Align Technology) orthodontic treatment as he desired to avoid the brackets and wires of traditional orthodontics due to aesthetic concerns during treatment. A previous dentist had proposed porcelain veneers from teeth Nos. 5 to 12 to correct the diastema, and the patient wished to ascertain if a more conservative approach was feasible. A comprehensive extra- and intraoral examination including a full-mouth series of radiographs, impressions and photographs, were taken for analysis.
The patient had a Class I molar and canine relationship with a 1.5-mm horizontal overjet and a 30% to 40% vertical overbite. The crown of tooth No. 8 appeared markedly inclined to the distal. Tooth No. 9 was also inclined, though less so than tooth No. 8. Radiographs revealed no evidence of periodontal involvement or caries.
Using a Dentagauge3 digital caliper (Erskine Dental) (Figure 2), height and width measurements of upper and lower anterior teeth were acquired from the preliminary study models. Table 1 shows the resultant measurements as well as height to width ratios of the teeth. These measurements were used to help guide a mathematically driven systematic protocol that allows for an expression of optimal tooth positioning and proportions.1
|Figure 1. Initial presentation. The patient had a 5-mm diastema between teeth Nos. 8 and 9. He requested a minimally invasive treatment to "straighten my teeth and close the space."||Figure 2. Photograph of the Dentagauge3 digital caliper (Erskin Dental) used to calculate height and widths of teeth.|
|Figure 3. ClinCheck screen capture of patient's initial presentation. Note the flat contour on the mesial surface of teeth Nos. 8 and 9.||Figure 4. ClinCheck screen capture of proposal of completion of Invisalign orthodontic treatment (Align Technology). The roots and crowns of teeth Nos. 8 and 9 appear parallel. A 2-mm diastema remains after orthodontic therapy.|
|Figure 5. View of patient's alignment after completion of Invisalign.|
To determine if there were any tooth size discrepancies between maxillary and mandibular teeth, a manually measured Anterior Bolton Index (ABI) of the arches was performed. Commonly used by orthodontists, an ABI is a ratio of the sum total of the mesiodistal widths of mandibular teeth over the sum total of the mesiodistal widths of the corresponding maxillary teeth.2 This analysis can be performed from first molar to contralateral first molar (total Bolton Analysis) or from canine to contralateral canine (ABI). Due to the fact that there was no anticipated change in the position of the first molars or premolars, only the ABI was performed. As seen in Table 2, the resultant ABI of 77.7 revealed no significant tooth size discrepancy.3,4
However, a noteworthy finding was evident when a critical look at tooth morphology was taken; both central incisors had flat contours on their mesial surfaces. Although the diastema closure could have been completed solely with orthodontic treatment, the concern was that the front teeth would have a "Chiclet look" resulting from 2 flat surfaces touching each other.5,6 Additionally, due to the root inclination and intertooth distance of the diastema, restoring only the central incisors at their current position with composite would have yielded unsatisfactory aesthetics, as the teeth would have looked excessively wide.
Using Erskine Dental's "anterior analysis and restorative system," which is based upon Golden Proportion ratios, it was calculated that the central incisors were one to 1.25 mm too narrow mesiodistally as compared to the mesiodistal widths of the lateral and canines.1,7 Moreover, the central incisors were also deemed too narrow considering this measurement proportionally to their incisal-gingival height when an idealized 80% height to width ratio is utilized (Table 3). Therefore, it was proposed to the patient that Invisalign orthodontic treatment would be used to move the teeth until the roots of teeth Nos. 8 and 9 appeared parallel; and this would then yield a predicted interproximal space of 1.5 to 2 mm. This diastema would then be closed using a nanohybrid composite and the Bioclear Matrix System (Bioclear) to build up the mesiodistal width of these teeth to match their predicted ideal width.
Following Invisalign protocol, upper and lower vinyl polysiloxane (VPS) impressions (Flexitime [Heraeus Kulzer]) were taken of the maxillary and mandibular arch. A VPS bite registration (Blu-Mousse [Parkell]) was also taken. Required photographs and radiographs were also submitted. Figure 3 shows the initial ClinCheck capture, while Figure 4 shows the ClinCheck capture of the proposed alignment at the completion of the Invisalign treatment. The Invisalign proposal was approved, and treatment was initiated.
The total orthodontic treatment called for 10 aligners, with aligners to be worn sequentially for 2 weeks at a time to achieve the desired alignment. Figure 5 shows the clinical situation at the end of the 10th aligner. The roots of teeth Nos. 8 and 9 appeared parallel and a 2-mm diastema, verified by digital calipers, was noted between the 2 teeth. Additionally, the patient opted to bleach his teeth during the final month of treatment using the aligner as a bleaching tray (Opalescence [Ultradent Products]). As a result, the patient went from a Vita shade of A3 to B1.
A diastema of such a small interproximal distance can present a restorative dilemma. The desired size, contour, and apparent axial inclination of each tooth may be difficult to control. The use of conventional mylar strips can cause an undercontoured and ultimately unaesthetic restoration.8 The Bioclear Matrix was used to eliminate the potential difficulties of diastema closure in this case.
|Figure 6. The Bioclear Matrix Selection and Space Closure Guide. The appropriate matrices were chosen to best close the resultant diastema. In the case presented here, 2 DC-201 Matrices were selected.||Figure 7. Occlusal and facial views of the Bioclear dedicated diastema closure matrix.|
|Figure 8. Demonstration of placement of Bioclear matricies. Note the aggressive cervical curvature.||Figure 9. Demonstration of composite "hips" or undercuts placed at the cervical area of involved teeth. These hips will facilitate interproximal wedge or Interproximator placement.|
|Figure 10. Demonstration of the Stage Wedging Technique. The aggressive wedging pressure against the composite hips compensated for the thickness of the 2 matrices and allows for a tight contact. Note that in the case presented here, an Interproximator was used.|
Using the Bioclear Matrix Selection and Space Closure Guide (Figure 6), it was determined that the 2 mm diastema would be closed with 2 back to back DC-201 matrices (Figure 7). The mesial surfaces of the teeth were cleaned with medium pumice and slightly prepared with an "infinity bevel."8 The DC-201 matrices were placed, taking care to slide the cervical edges of the matrices between the tooth and the gingiva. No wedging was used at this point, as the shape of the matrices allowed for them to remain in a stable position (Figure 8). A bonding agent (Surpass [Apex Dental]) was then applied to the teeth.
Using a small amount of warmed chromatic nanofilled composite (B1 Enamel Herculite Ultra [Kerr]), a small "hip" or undercut area was established at the cervical third of the interproximal areas of both teeth Nos. 8 and 9 simultaneously (Figure 9). Once a small "hip" had been placed and light-cured, an aggressive wedging force with a traditional wedge or Bioclear Interproximator (Bioclear), as was used in this case, was implemented to separate the teeth (Figure 10). Because of the limitations of flat Mylar, in the past most clinicians have applied a matrix and restored one central incisor at a time in order to achieve a tight contact. With the advent of the Bioclear diastema closure matrix, anterior teeth can be adequately displaced with strong wedging pressure after the "hips" are placed and light-cured. This will easily compensate for the 2 sheets (50 µm each) of Mylar in order to achieve a tight contact. The central incisors can be restored simultaneously, which is a more predictable way to achieve symmetry; with a further advantage of being more expedient. This technique is referred to as the Staged Wedging Technique. Positioning the matrices to ensure the proper axial inclination of the restorations, additional warmed B1 composite material was placed and both teeth were restored simultaneously.
|Figure 11. View after removal of Bioclear Matrices and Interproximator. Although the teeth appear symmetrical, a resultant "black triangle" is evident.||Figure 12. Final result one week postoperatively showing complete resolution of the "black triangle" between teeth Nos. 8 and 9 and an aesthetic and harmonious smile.|
Figure 11 shows the teeth immediately after removal of the Bioclear matrices and Interproximator. The teeth were finished and polished using Enhance (Kerr) and PoGo points and wheels (Kerr). A high luster was then achieved with a fine particle aluminum oxide polishing paste on a felt wheel (Enamelize [Cosmedent]). The desired contour, contact, and vertical axial inclination were achieved. Final width measurements of teeth Nos. 8 and 9 were 8.19 mm and 8.24 mm respectively, which was close to the predicted ideal width values of Table 3. A black triangle was evident. This was attributed to the use of the Interproximator. It was anticipated that the situation would resolve itself as there was now approximately 5 mm from the newly established contact point to the crest of bone, a distance which has shown to allow predictable papillary fill between restorations.9 The aggressive cervical curvature of the Bioclear Matrix allows for a more apical contact point, thereby maximizing the probability for a papillary fill. The one-week follow-up shows resolution of the black triangle as well as symmetrical, aesthetically pleasing restorations (Figure 12).
Following the restorative treatment, new impressions were taken and the patient was given clear removable retainers to maintain tooth position.
An interdisciplinary approach was used to provide the patient with an aesthetic result while providing minimally invasive treatment. Using solely either an orthodontic or restorative approach would not have yielded as satisfactory a result.
A critical factor in achieving success in this case was the application of diagnostic modalities from both orthodontics (Bolton Analysis) and restorative dentistry (Golden Proportion). This allowed for a mathematically-derived restorative blueprint.1,10-13 In this case, the ABI did not reveal a tooth size discrepancy between maxillary and mandibular teeth widths. However, an analysis of Golden Proportion revealed that the maxillary central incisors were slightly narrow relative to both the widths of the adjacent laterals and canines as well as to the height to width ratio of the incisors themselves.
For more complex orthodontic-restorative cases, the use of Bolton indices can prove to be an invaluable diagnostic tool.14 When tooth size discrepancies exist, teeth and roots can be moved orthodontically to a position that will allow for an optimal expression of Golden Proportion.15 In the case presented here, the teeth were tipped until that the roots of the maxillary central incisors appeared parallel. This parallel position was chosen for proper proportioning as well as its positive effect on papillary fill.16,17
A subtle but significant feature of the patented diastema closure matrix is its ability to form the scaffolding required to encourage papilla regeneration concomitant with diastema closure. The key to ideal papilla regeneration in the diastema closure procedure––whether performed with porcelain or composite––is to provide aggressive cervical curvature that begins subgingivally. Many traditional diastema treatments achieve closure with composite or porcelain that reaches mesiodistally; "on top" of the gingival; these central incisors were treated using the Bioclear DC-201 matrix. The biconcave gingival contour of the matrix provides a shape that has heretofore been predictably created only by using porcelain as the restorative material. Most importantly, it allows predictable deflection of the soft tissue to accomplish subgingival alteration of the emergence profile. The aggressive cervical curvature transitions to a fairly flat shape in the incisal two thirds of the matrix. The immediate postoperative image demonstrates the significant difference that a double concave precurved matrix can provide. The regenerated papilla, whether immediate, or as in this case, within a few days, completes the space closure, and the static tension of the gingiva against the interproximal tooth surfaces provides a youthful seal, eliminating bacterial colonization and debris accumulation.
The Bioclear Matrix System, with varying matrices of known widths, allows for a predictable and aesthetic restorative result. In this case, because the central incisors were of nearly equal widths preoperatively, the desired increase in width to close the resultant diastema was the same. Therefore, 2 matrices of equal size were chosen. For other such cases, once the desired size of the teeth is known, an appropriate combination of matrices can be used to not only close existing diastema, but to also restore the involved teeth to their proper balanced widths.
The utilization of algorithms derived from existing diagnostic modalities was instrumental in determining the ideal positioning of the teeth. The combined use of Invisalign and the Bioclear Matrix System allowed for a predictable, minimally invasive solution to a complex aesthetic problem. Future applications could include a CAD/CAM application whereby digitally acquired models could be analyzed and a proposed final othodontic-periodontic-restorative result could be mathematically prescribed before any treatment is started.
CLOSING COMMENTS (DR. CLARK)
Patients are generally pleased when an outcome provides teeth that are "straight and white." However, a commitment to the most ideal outcome with attention to subtle details beyond the layperson's grasp should be foremost in our minds as treatment plans are devised. In this instance, Dr. Volker went above and beyond the standard of care with additional analysis and treatment to achieve ideal tooth size relationships. This transformed the patient's outcome, elevating it from good to great.
The minimally invasive philosophy was adhered to in an admirable fashion. As opposed to the previous clinician's treatment plan of porcelain veneers, the orthodontic/bleaching/ composite triumvirate provided a gorgeous and natural result, superior to a man-made smile. While we routinely prescribe porcelain veneers for our patents, only a small percentage of us have laminates on our own teeth, a cognitive dissonance, to borrow a line from my friend Gordon Christensen.
- Levin EI. Dental esthetics and the golden proportion. J Prosthet Dent. 1978;40:244-252.
- Bolton WA. Disharmony in tooth size and its relation to the analysis and treatment of malocclusion. Angle Orthodontist. 1958;28:113-130.
- Crosby DR, Alexander CG. The occurrence of tooth size discrepancies among different malocclusion groups. Am J Orthod Dentofacial Orthop. 1989;95:457-461.
- Freeman JE, Maskeroni AJ, Lorton L. Frequency of Bolton tooth-size discrepancies among orthodontic patients. Am J Orthod Dentofacial Orthop. 1996;110:24-27.
- Waldman AB. Smile design for the adolescent patient—interdisciplinary management of anterior tooth size discrepancies. J Calif Dent Assoc. 2008;36:365-372.
- Chu FC, Siu AS, Newsome PR, et al. Management of median diastema. Gen Dent. 2001;49:282-287.
- Erskine-Smith C. Solving spacing problems and designing smiles using a new measuring system. http://erskinedental.com/products/casestudy.html. Accessed August 16, 2011.
- Clark D. Correction of the "black triangle": restoratively driven papilla regeneration. Dent Today. 2009;28:150-155.
- Tarnow DP, Magner AW, Fletcher P. The effect of the distance from the contact point to the crest of bone on the presence or absence of the interproximal dental papilla. J Periodontol. 1992;63:995-996.
- Javaheri DS, Shahnavaz S. Utilizing the concept of the golden proportion. Dent Today. 2002;21:96-101.
- Gaidyte A, Latkauskiene D, Baubiniene D, et al. Analysis of tooth size discrepancy (Bolton index) among patients of orthodontic clinic at Kaunas Medical University. Stomatologija. 2003;5:27-30.
- De Araujo EM Jr, Fortkamp S, Baratieri LN. Closure of diastema and gingival recontouring using direct adhesive restorations: a case report. J Esthet Restor Dent. 2009;21:229-240.
- Hou HM, Wong RWK, Hägg U. The uses of orthodontic study models in diagnosis and treatment planning. Hong Kong Dental Journal. 2006;3:107-115.
- Wise RJ, Nevins M. Anterior tooth site analysis (Bolton Index): how to determine anterior diastema closure. Int J Periodontics Restorative Dent. 1988;8:9-23.
- Furuse AY, Franco EJ, Mondelli J. Esthetic and functional restoration for an anterior open occlusal relationship with multiple diastemata: a multidisciplinary approach. J Prosthet Dent. 2008;99:91-94.
- Tanaka OM, Furquim BD, Pascotto RC, et al. The dilemma of the open gingival embrasure between maxillary central incisors. J Contemp Dent Pract. 2008;9:92-98.
- Sharma AA, Park JH. Esthetic considerations in interdental papilla: remediation and regeneration. J Esthet Restor Dent. 2010;22:18-28.
Disclosure: Dr. Volker reports no disclosures.
Disclosure: Dr. Clark is the owner of Bioclear Matrix Systems.
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