Written by Jerry Simon, DDS Tuesday, 31 August 2004 19:00
The ratio of Golden Proportion, 1 to 0.618, can be found in a remarkable number of places and plays a huge role in both modern and historical structures and forms. The earliest references to Golden Proportion date back at least 2,500 years but cannot be traced to a particular event or originator. It is the underlying proportion of Egypt’s Pyramids and the Parthenon in Athens and was a central element in Plato’s Timaeus, which was one of the earliest texts to document the physics of the cosmos. In the 14th century, Leonardo da Vinci first coined the term “Divine Proportion,” and it served a central role in the drawing of figures in numerous great works of art, including “The Last Supper.”1
In the hundreds of years that passed, observations of “Divine Proportion,” later known as Golden Proportion, were identified and documented in all aspects of life, from the designs on snails (Figure 1) to the proportion of teeth. Perhaps the most interesting work is that of Dr. Stephen Marquardt, an oral and maxillofacial surgeon, who developed the Marquardt Beauty Mask, which can successfully identify beauty across all races, cultures, and areas (Figure 2).
|Figure 1. Golden Proportion in nature.||Figure 2. Marquardt Beauty Mask.|
When applied to dentistry, Golden Proportion states that the teeth look most harmonious when viewed from the front if the amount of visible tooth surface of the central incisors to lateral incisors forms a ratio of 1.6 to 1 (Figure 3). One of the more difficult cosmetic cases is where, in addition to teeth that are crooked and dark, the teeth are disproportionately sized. Such was the case of a 25-year-old female patient of mine who always hated her smile. As a child she had orthodontic treatment to straighten her teeth, but the crowding returned as a young adult. Figure 4 shows the severe crowding in the upper anterior segment that forced her laterals, especially tooth No. 7, out of the arch. In addition, her central incisors were disproportionately large compared to her laterals, creating a bucktooth appearance that was equally if not more bothersome to the patient (Figures 5 and 6). Her existing ratio of visible tooth structure between the central and lateral incisors was 1 to 1.85.
|Figure 3. Ratio of central incisors to lateral incisors is 1.6 to 1.||Figure 4. Crowding in maxillary anterior area.|
|Figure 5. Visible tooth ratio of 1.85 to 1.||Figure 6. Before: Crowding and disproportional central incisors.|
The treatment objective of this case was to create both an aesthetically pleasing and biomechanically correct smile. To explore treatment options, preoperative study models were altered by narrowing the central incisors and both moving and widening the lateral incisors (Figure 7). The models were presented to the patient and were extremely well received.
|Figure 7. Study model for patient presentation.|
The next step was to determine the path to these ideal treatment results. The theoretical options were more orthodontic treatment and porcelain veneers. Orthodontics would require the extraction of teeth to create more arch space in which to fit all of the teeth. However, this would not improve the proportion of the teeth, which was one of the patient’s main concerns. Due to failure to meet all essential criteria, and the time and inconvenience of orthodontics, this treatment plan was rejected.
An alternative was to prepare porcelain veneers for 8 upper teeth, from first premolar to first premolar. This would allow us to refine all of the visible upper front teeth and create a matching size, shape, and shade. Due to budget limitations and interest in the most conservative possible approach (no extractions and preparation of the minimal number of teeth), a treatment plan preparing only the 4 incisors was requested. The other teeth would be bleached with in-office ZOOM (Discus Dental) to allow us to whiten the patient’s teeth to approximate closely the 4 new veneers. Since her teeth were in a yellow cast and a shade of A2 at only 25 years old, we targeted a final shade of B1 or lighter.
The preparation phase required narrowing the central incisors and creating room for the lateral incisors to bring the teeth closer to a Golden Proportion ratio. This was much more aggressive than traditional conservative veneer preparations, but critical to achieving the case objectives. The subgingival portion of the teeth needed to be prepared first to narrow the teeth physically. The contact areas would need to be opened, and the necks of the central incisors would need to be narrowed to ensure that the resulting final veneers could be made smaller to fit Golden Proportion. After the subgingival areas were prepared and the gingival embrasures were opened, the supragingival areas were prepared.
|Figure 8. Prepared teeth. Note embrasure space that was created.|
Figure 8 shows the preparations; note the embrasure space that was created. The basic preparations were done with a Diamant 856-021-9 MLX (Diamant), and then the interradicular root space was opened with a very small and narrow Diamant 132-008 F, 132-008 EF, and 132-008 UF. These come in a series of fine, very fine, and ultra fine that are used sequentially to narrow the root and then to create a smooth root surface that will not be covered by the final veneer. Figure 9 shows the final Feldspathic veneers from daVinci Dental Studios on the model, placed on top of the Panadent Golden Proportion Guide. Figures 10, 11, and 12 show a comparison and the final results. Note the natural look regarding the straight alignment and proper proportion to both her arch and the rest of her facial features. It is exciting to see the dramatic results from a relatively conservative technique of preparing just 4 teeth.
|Figure 9. Final veneers on Golden Proportion Guide.||Figure 10. Final veneers. Note alignment and proportion.|
|Figure 11. Patient prior to treatment.||Figure 12. Completed case.|
Many dental patients are unhappy with their smile but believe a beautiful smile is outside their budget. The first step is to listen to the patient in order to understand what his or her primary concerns are. The second step is to examine carefully and analyze the case to develop a treatment plan that will fulfill as much as possible of the patient’s desires within the context of his or her constraints (financial or otherwise). Also, remember that dentistry doesn’t end when the last veneer is placed or the last bill is paid. The final step is to maintain a strong relationship with your patients to ensure good oral hygiene and restorations that are as long-lasting as they are beautiful.
1. Huntley HE. The Divine Proportion: A Study in Mathematical Beauty. Dover Publications: ISBN 0486222543; 1970.
Dr. Simon has been an active dental practitioner in Stamford, Conn, for more than 30 years with a focus on bite dysfunctions. The author of the book Stop Headaches Now: Take the Bite Out of Headaches, he can be reached at best-bite.com or (888) 865-7335. Disclosure: Dr. Simon is the inventor of the Best-Bite Discluder.
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