COSMETIC & RESTORATIVE CARE |
Simulated shape design
Helping patients decide their esthetic ideal
IAN VAN ZYL, B.D.S., D.D.S., M.S.PROS. and
MARC GEISSBERGER, D.D.S., M.A.
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ABSTRACT
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Background. Esthetic care is changing dentistry from a need-based to a want-based practice. Patients are asking for esthetic treatment, and clinicians are retooling their practices to satisfy this need. One important part of providing esthetic dentistry is ensuring that the patient is as well-informed as possible about treatment outcomes.
Description of Technique. This article describes a tool dentists can use to show patients potential tooth sizes, shapes and arrangements before carrying out treatment. Simulated shape design, or SSD, is a reversible method of demonstrating potential esthetic outcomes that involves creating trial restoration shapes and placing them over a patient’s teeth. SSD is a simple technique that any dentist can perform. In essence, the technician makes new tooth shapes in wax, the dentist places these in the patient’s mouth and the patient evaluates them. The dentist then makes modifications in the SSD, which he or she reports to the technician.
Clinical Implications. With the decisions of shape, arrangement and size made at chairside, the whole flow of esthetic treatment can be handled smoothly. Preparations can be cut more accurately to better support the restorative material; decisions can be made to open or not open the contacts; and shapes can be agreed on in the earliest stage of evaluation, then duplicated faithfully in the provisional and final restorations. There are no surprises for the patient, the dentist or the technician. Both the esthetic (smile design) and functional elements (anterior guidance) of the restoration can be checked with SSD. SSD could become the standard in determining whether or not to proceed with esthetic treatment.
Dentists or technicians traditionally have made choices about esthetic treatment as they believed best, without consulting patients to any large degree. However, dentists need to investigate what patients want and determine if it is feasible. As the distinction between mandatory and elective dentistry becomes more clearly defined,1 patients are expecting to have more say in the decisions about their esthetic care.2,3 Simply listening empathetically to patients4 is not enough any more. Patients are educated enough to make their own choices, and they want to be more actively involved in choices about their appearance.
Simulated shape design is a method by which the dentist and patient can collaboratively work out tooth shape and arrangement issues.
One problem in esthetic dentistry is the dentist’s inability to communicate to the patient how proposed esthetic work will look2 and function on completion of treatment. In fact, the dentist may not be able to visualize the final result, because this is left in large part to the technician.
This article describes a novel approach to assessing dental patients for esthetic treatment, termed "simulated shape design," or SSD. SSD is a method by which the dentist and patient can collaboratively work out tooth shape and arrangement issues, and it is key to the geometry of smile design. It is a clinical technique that provides both patient and dentist with extensive information about proposed esthetic treatment. SSD is completely reversible and does not commit the dentist or the patient to treatment. The technique allows the patient to see proposed anterior esthetic changes and decide whether or not to progress to veneers, crowns or anterior composite restorations.
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PROVIDING ESTHETIC INFORMATION
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Patients need information about esthetic treatment to decide whether or not to accept treatment. Various techniques are available for dentists to show patients a proposed new smile design. They include adding white wax to patients’ teeth,5 showing patients wax-ups,5,6 displaying before-and-after pictures of completed cases6 and demonstrating possible results by means of computer/video imaging.3,6 Belser and colleagues,7 Magne and colleagues8 and Adar9 described a self-curing acrylic mask placed on the patient’s teeth to help both the technician and the patient see the proposed incisal edge position. This "mock-up" technique10 required the direct addition and sculpting of flowable resin-based composite to the anterior teeth to determine tooth shape and position.
SSD improves on the mock-up technique. It requires less clinical skill, as the wax addition can be delegated to a technician. Involving the technician early in making the shape decision gives direction to the whole process. Function of the anterior teeth depends on the lingual surfaces of the maxillary teeth and the labial surfaces of the mandibular teeth. It is easier to decide how to improve this function using wax on stone, using the improved visibility of an articulator, than it is to try to guess the lingual shapes with direct addition of composite in the mouth. Therefore, the SSD technique is easier to perform and also can be used to plan proposed changes in anterior guidance.
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THE TECHNIQUE
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The best vehicle for communicating the benefits and drawbacks of esthetic anterior restorations is the final product. Unfortunately, by this stage, there is no "out" for either patient or dentist; the commitment to treatment has been made. To combat this difficulty, we developed SSD. SSD shows patients how they will look after treatment—even in cases with several possible solutions.
SSD requires three stages:
- – make a model;
- – transfer the model to the mouth;
- – evaluate and adjust the proposed restoration according to the patient’s wishes and the dentist’s professional opinion.
The patient in the case photos shown was treated by one of the authors (M.G.).
Make a model.
Before beginning the SSD, the dentist should take a baseline photograph of the patient (Figure 1
), then take accurate alginate impressions. The dentist then mounts stone casts made from the impressions—which clearly show the existing tooth shape, free gingival margin, palate and vestibule—in centric occlusion with no bite registration, using a facebow on a semiadjustable articulator (Figure 2).
At the time of facebow transfer, the dentist assesses any difference between the esthetic plane and the Frankfort horizontal plane11 by using a bite stick or clinometer.12
The technician waxes up the cast (Figure 3) using some of the principles of macroesthetic smile design.13 The diagnostic wax-up helps both dentist and patient make choices about veneers vs. full-coverage restorations, the need to improve anterior guidance, the need to involve lower incisors by recontouring or restoration, and the need for altering gingival contours (Figure 4). A groove cut into the free gingival margin of the cast (Figure 5) pinches off most of the clinical flash. These self-trimming margins speed up the placement of the SSD.
Transfer the information to the mouth.
An impression of the wax-up is taken in putty—the esthetic matrix (Figure 6). The dentist tries the esthetic matrix in the patient’s mouth and marks the midline to help subsequent placement, then dries the teeth using 2 x 2-inch gauze. He or she fills the esthetic matrix three-quarters full with provisional material (such as Integrity, Dentsply Caulk) (Figure 7) and seats it firmly over the teeth. After the material sets initially, the dentist removes the esthetic matrix facially, leaving the SSD on the teeth (Figure 8). The putty ridge (Figure 8) pinches off most of the facial flash, and the lingual excess can be peeled off with a spoon. Integrity has an oily surface shine and does not require polishing. The patient is taken to a wall mirror and asked to evaluate the proposed esthetic enhancements (Figure 9).
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Figure 7. Esthetic matrix three-quarters filled with provisional material (Integrity, Dentsply Caulk).
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Function also can be checked with SSD (I. van Zyl, B.D.S., D.D.S., M.S.; D. Catagna, D.D.S.; L. Loos, D.D.S., M.A., unpublished data, 2001).
Evaluation/adjustment.
The most important feature of SSD is that patients can see the change in tooth shape in their own mouths. It provides a working model of the proposed restoration. Adjustments can be made at the patient’s request. Of course, the patient must know that the temporary material has different optical properties from the restorative material, so it will not look exactly the same.
With the size, shape and arrangement decisions made, the dentist removes the simulated shapes using a spoon excavator.
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USES OF SIMULATED SMILE DESIGN
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Information derived from SSD is extensive. Patients are excited about it, because they can see what the dentist can do; they do not need to use their imaginations. It is equally important for the patient to better understand the dentist’s restorative limitations, and with SSD, they can see those limitations with their own eyes. Should the patient like the shapes generated by the SSD technique, this information can be used directly by the dental laboratory in fabrication of the final restorations.
The SSD technique helps identify patients with unrealistic expectations. We found that patients’ expressions (which we photographed) and body language told us more about their true expectations than their words did.
With SSD in place on the teeth, the dentist can check esthetic and functional factors. These include the midline, arch form, profile, long axes, embrasure form, line angles, proportion, symmetry/asymmetry, amount of tooth revealed, tooth thickness, gingival contour, tooth macroanatomy and microanatomy, incisal edge position, smile line, shade and anterior guidance, speech, and the number and area of occlusal contacts in the edge-to-edge position.
SSD is an additive technique. There are a few situations in which SSD is of no use.
- – When teeth have supraerupted or already look long owing to recession, SSD will be of limited use.
- – When the anterior teeth already are prominent (facially placed), further addition material on the facial aspect may detract from esthetics.
When a subtractive rather than an additive technique is called for, the dentist can use a dark marker on the teeth to give the illusion of shorter teeth.
Other postulated uses of SSD include trying in full-mouth reconstructions from an articulated wax-up to verify function before having castings made. Orthodontists also could transfer Kesling setups to the mouth to show proposed final orthodontic treatment outcomes.
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SUMMARY
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No matter how one considers it, dentists are model makers. Technicians make models on casts, and dentists make them in the mouth. This modeling ability gives dentists a method for checking their work for form and function. As esthetics is such a subjective area,14 patients need the information from SSD to decide on the esthetic aspects of their reconstruction. Dentists need patients to tell them what they consider beautiful. SSD can enable dentists to give patients the smiles they envision, not the smiles dentists envision for them.
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FOOTNOTES
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Dr. van Zyl is an assistant professor, Fixed Prosthodontics, University of the Pacific School of Dentistry, San Francisco; the co-director, University of the Pacific Esthetic Clinic, San Francisco; and an instructor, Comprehensive Approach Necessary to Visualize Aesthetic Success, University of the Pacific, San Francisco. Address reprint requests to Dr. van Zyl at the University of the Pacific School of Dentistry, 2155 Webster St., San Francisco, Calif. 94115, e-mail "ivanzyl{at}uop.edu".
Dr. Geissberger is the co-chair, Restorative Dentistry, University of the Pacific School of Dentistry, San Francisco; the co-director, University of the Pacific Esthetic Clinic, San Francisco; and director, Comprehensive Approach Necessary to Visualize Aesthetic Success, University of the Pacific, San Francisco.
Information on the technique described in this article—of which Dr. van Zyl is the inventor and developer—was first presented at the California Dental Association’s Fall Scientific Sessions, San Francisco, Sept. 16, 2000.
The authors give special thanks to Dan Castagna, D.D.S., and Larry Loos, D.D.S., M.A., for their help.
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REFERENCES
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- Hornbrook D, Koczarski M. Functional anterior aesthetics. Course presented at: Pacific Aesthetic Continuum (P.A.C.)-Live; July 29, 2000; San Francisco.
- Frankfort horizontal plane. In: Glossary of prosthodontic terms. 7th ed. St. Louis: Mosby; 1999:73.
- Morley J, Eubank J. The macroesthetic elements of smile design. JADA 2001;132:39–45.
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TOP
ABSTRACT
PROVIDING ESTHETIC INFORMATION
