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Written by Dino Javaheri, DMD Sunday, 01 June 2003 00:00
There are 3 basic options for cosmetic enhancement of the crowded anterior dentition: veneers, orthodontics, or a combination of both. Each of these treatment modalities has its own advantages and disadvantages.
In addition to correcting minor to moderate crowding, veneers can also change the color and shapes of teeth. Veneers offer patients a quick aesthetic option, but involve a compromise in tooth structure and cannot always correct severe crowding or occlusal problems. Placing veneers on a crowded dentition often involves very aggressive preparations, and some patients may not be amenable to removal of their tooth structure.
Orthodontics offers patients a conservative solution, but may take longer to correct a crowding problem than the patient is willing to wait. Also, the final results may not be to the patient’s expectations if the ideal shapes or length of teeth cannot be achieved.
Without proper planning, both treatment modalities may result in unsatisfactory results and disappointment. To ensure that the final results will please the patient’s expectations, the practitioner must be able to envision the final results and plan the process for achieving the desired results.
In order to present the perfect treatment plan for each patient, proper planning must be done prior to any treatment. The doctor and patient must both be able to envision the final results during treatment planning. In order to perform a complete aesthetic/occlusal exam, a full set of x-rays, mounted models in centric relation with a face-bow, and photos are necessary. The photos are useful in establishing the incisal edge position, length and width of central incisors, smile line, and other smile design principles. The purpose of the models is for occlusal analysis.
After a complete exam, the aesthetic and occlusal goals can be outlined. The treatment plan serves as a road map for the dentist and laboratory technician to achieve those desired final results. In order to decide the proper treatment modality for the crowded dentition, factors such as patient motivation, time, cost, conservation of tooth structure, and goals must be considered.
QUESTIONS TO ASK
Prior to determining the possible treatment modality for the crowded dentition, several questions must be answered.1-3
(1) Will veneers be necessary for cosmetic reasons even if orthodontic treatment is completed? The answer to this question often depends on the patient’s expectations and the condition of the existing dentition. If the patient’s cosmetic expectations can be met by orthodontically straightening and bleaching the teeth, then orthodontics should be seriously considered. However, if the teeth need to be lengthened or the sizes of the teeth do not match each other, then veneers are required to correct the tooth shape discrepancies even if orthodontic therapy is completed. In cases where veneers are necessary for a cosmetic result, orthodontics may not provide much benefit. However, orthodontics can still be of great benefit in cases of crowded teeth. By placing the teeth in the correct position, aggressive preparation of teeth can be avoided.
(2) Can the occlusion be managed without orthodontic treatment? In the first question, we were evaluating our treatment options from a cosmetic standpoint. In this question, we are assessing how we can achieve functional results. If the patient’s teeth are malpositioned, orthodontics can reposition the teeth into proper function. In some cases, restorative options may require root canal therapy and severe compromise of tooth structure. In severe cases, restorative options may be nonexistent. With crowded or rotated teeth, the patient often needs to make the final decision between orthodontics and a limited number of veneers or full-mouth rehabilitation with crowns. In other cases, orthodontics may improve the occlusion, but provide no real benefit if the same number of restorations will be necessary to ensure a functional outcome. So, a decision needs to be made from a functional standpoint if orthodontics is necessary, beneficial, or ineffectual.
(3) Are gingival tissue heights in line and in correct position? Often, tissue height discrepancies can be corrected with gingivectomy procedures. However, in certain situations, crown lengthening is needed for osseous recontouring to correct the gingival levels. This may lead to a compromise in crown-to-root ratio and expose root structures. Another option is to correct the gingival levels with orthodontics, then correct the incisal edge positions by restorative treatment.
|Figure 1. Preoperative view of patient presenting with aesthetic concerns.||Figure 2. Preoperative retracted view of left side.|
|Figure 3. Preoperative retracted view of right side.|
A 45-year-old female patient presented for cosmetic treatment (Figures 1 through 3). Her main concern was maxillary and mandibular anterior crowding. The patient was also unhappy that the length and shapes of her central incisors did not match each other. She wanted to have a symmetrical, uniform, pleasing smile. In order to evaluate the patient’s smile, a complete exam was performed, which included photos and mounted models. A clinical exam revealed healthy teeth with all existing restorations in good condition. The patient had a past history of periodontal disease. She had periodontal surgery approximately 10 years ago and has maintained good periodontal health. The tissue heights were slightly uneven, resulting in the appearance of disproportional teeth sizes. The anterior crowding and rotated canines produced a group function occlusion. The patient did not report any tooth pain, and there was no history of TMJ symptoms.
Determining the location of the incisal edge of the central incisors is one of the most important factors for a successful reconstruction.4 The 3 determinants to be considered are occlusion, phonetics, and aesthetics. The occlusion should be characterized by anterior guidance, cuspid disclusion, lack of slide between centric relation and centric occlusion, absence of balancing or working side interferences, and equal and simultaneous force on each tooth when the teeth are in contact, with no deflection when additional force is exerted. Phonetics is also used as a guide to determine the position of the incisal edge. During the pronunciation of f or v sounds, the maxillary anterior teeth should lightly touch the vermilion border of the lower lip. Finally, both the clinician and the patient should evaluate the aesthetics of the proposed incisal edge position.
|Figure 4. Tracing from preoperative photograph to apply smile design principles.||Figure 5. Proposed incisal edge position and gingival heights are marked.|
|Figure 6. New central incisor length is measured using a ruler.||Figure 7. A 75% width to height ratio is determined and marked.|
|Figure 8. The proposed shapes of the central incisors are drawn using the length and width measurements.||Figure 9. The width of the central incisors are reduced by 62% to give the width of the lateral incisors.|
|Figure 10. The proposed shapes of the lateral incisors are drawn.|
After determining the incisal edge position, the length and tissue heights of the central incisors are established.5 From this point, a trace drawing of a retracted straight-on photo can be used to apply design concepts. Using tracing paper, the patient’s teeth are outlined (Figure 4). The new incisal edge position and the gingival position are placed on the working outline (Figure 5). To give the central incisors a distinct rectangular shape, the width-to-height ratio should be approximately 75%.6-7 The length of the central incisors is measured on the photograph and multiplied by 0.75 to give the correct photographic width for these teeth (Figure 6). After marking the width measurement, the proposed shape of the new central incisors can be drawn (Figures 7 and 8). At this point, the width of the other teeth can be estimated using the Golden Proportion. The Golden Proportion is meant to be used only as a guideline for establishing symmetry since it is rarely found in the natural dentition.8 The widths of the centrals were multiplied by the Golden Proportion ratio of 0.62, thereby establishing the width of the lateral incisors (Figure 9).6-7 This new width of the lateral incisors was marked and the shapes were drawn (Figure 10). The same technique is utilized for the profile view of the cuspids and premolars.
This tracing helps to define the treatment plan. The tracing shows where the tissue and teeth need to be placed for the end result. Now, the 3 questions noted previously can be applied to the preoperative photos and tracing.
Will veneers be necessary even if orthodontic treatment is completed? In this case, even if orthodontic treatment is accomplished, to achieve the correct length and sizes of the teeth, veneers will be necessary. Therefore, to realize cosmetic objectives, orthodontics will not be necessary.
Can the occlusion be managed without orthodontic treatment? This question could not be answered from photos, but instead from the mounted models and a diagnostic wax-up. Two options existed for establishing proper occlusion for this patient. The case could be treated with orthodontics or as a full-mouth rehabilitation case with crowns. Even with crowns, ideal results could not be reached in the lower anterior area because of the level of crowding. The patient also felt the amount of reduction of tooth structure required for full-mouth rehabilitation was too aggressive and chose to correct occlusion with orthodontics.
Are gingival tissue heights in line and in correct position? The tissue heights were uneven; however, it was possible to easily correct this with gingivectomy. Tissue heights were not a factor in determining the treatment modality.
|Figure 11. Full smile view after orthodontics and extraction of a lower central incisor.|
To correct the occlusion problems, the proposed treatment goals, including models and tracing, were reviewed with an orthodontist. The orthodontist recommended extraction of a lower incisor to create space. Orthodontic therapy was accomplished over a 9-month period (Figure 11).
|Figure 12. Retracted view of gingival contouring and composite mock-up.||Figure 13. The final smile after orthodontics and 8 maxillary veneers.|
|Figure 14. Retracted view of left side. Note improved occlusion.||Figure 15. Retracted view of right side. Note improved occlusion.|
After orthodontic therapy was completed, a new smile analysis was performed. In order to achieve the youthful and uniform smile the patient desired, tissue recontouring and a clinical mock-up were completed (Figure 12). The proposed new length was evaluated for aesthetics, phonetics, and occlusion. After the patient’s approval, 8 maxillary veneers were completed to correct the remaining aesthetic issues (Figures 13 through 15).
Because of the inclusion of orthodontics into the treatment plan, both aesthetic and occlusion results were enhanced. Also, the veneer preparations were very conservative since the teeth were aligned into the proper position. The patient was very pleased with the final results.
The design elements presented in this article do not represent a complete discussion of smile design techniques or treatment planning. However, the principles presented in this article help to determine whether an aesthetic case should be treated by orthodontics, restorative treatment, or both.
The author would like to thank Dr. Robert Brown (Danville, Calif) for completing the orthodontic phase and Frontier Dental Laboratory (Citrus Heights, Calif) for fabricating the restorations presented in this article.
1. Kokich VG, Spear FM. Guidelines for managing the orthodontic-restorative patient. Semin Orthod. 1997;3(1):3-20.
2. Moskowitz ME, Nayyar A. Determinants of dental esthetics: a rational for smile analysis and treatment. Compend Contin Educ Dent. 1995;16(12):1164,1166.
3. Morely J, Eubank J. Macroesthetic elements of smile design. J Am Dent Assoc. 2001;132(1):39-45.
4. Spear F. The maxillary central incisal edge: a key to esthetic and functional treatment planning. Compend Contin Educ Dent. 1999;20(6):512-6.
5. Javaheri DS, Shahnavaz S. Utilizing the concept of the golden proportion. Dent Today. 2002 Jun;21(6):96-101.
6. Morely J. Smile Design – Specific considerations. J Calif Dent Assoc. 1997;25(9):633 7.
7. Gillen RJ, Schwartz RS, Hilton TJ, Evans DB. An analysis of selected normative tooth proportions. Int J Prosthodont. 1994;7(5):410-7.
8. Wagner IV, Carlsson GE, Ekstrand K, Odman P, Schneider N. A comparative study of assessment of dental appearance by dentists, dental technicians, and laymen using computer-aided image manipulation. J Esthet Dent. 1996;8(5):199-205.
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