Can They Really Be Opposite? A New Look at Four Critical Aspects of Anterior Dental Morphology

18/05/2012 at 1:56 pm #15507

Anonymous

Figure 1

Figure 2 The resin-bonded restoration for this patient used one pontic. This visual effect was successful because of the basic similarities in width and length of the mandibular anterior group of teeth. It is not one tooth that appears to be two—it is five teeth that appear as six (dental laboratory technology by daVinci Dental Studios, Woodland Hills, CA).
Figure 3

Figure 2

Figure 3 The patient presented with a failing, full-coverage fixed dental prosthesis from the maxillary right canine to the maxillary left canine. The width of the lateral incisors was very similar to the adjacent central incisors. The overall effect was unnatural. There were also considerable gingival margin height disparities.
Figure 4

Figure 3

Figure 4 The patient’s full smile showed a lip aperture that limits the esthetic display to the coronal aspects of these teeth, and therefore, the treatment plan focused on correcting the width–length discrepancies of the crowns, not the gingival margin height disparities nor the issues of root exposure.

Figure 4

Figure 5 The treatment included expansion of each central incisor pontic and reduction in width of the lateral incisor crowns so that natural appearing width–length proportions (1.5 mm to 2 mm width differences) could be re-established.

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Figure 6 Postoperative smile view (dental laboratory technology by Jonathan Lee, Dental Ceramic Arts, Bryn Mawr, PA).

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Figure 7 The bilateral symmetry of the mandibular central incisor (reprinted with permission. Kraus et al13).

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Figure 8 Natural anterior teeth positioned at physiologic emergence angles (reprinted with permission. Kraus et al13).

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Figure 9 Diagram of a simulated observer’s perspective on the maxillary and mandibular anterior teeth.

Figure 9

Figure 10 Diagram illustrating the natural appearance of the mandibular anterior incisal edges from the observer’s perspective.

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Figure 11 Diagrammatic representation of an anatomically correct incisal embrasure configuration for six mandibular anterior teeth. Note that this is a “lab bench” view (teeth positioned vertically upright) not a functional view.

Figure 11

Figure 12 The patient demonstrates the functionally oriented, observer’s perspective known as “the view.” The apparent separations and irregularities are a function of lingual, not labial anatomy.

Figure 12

Figure 13 The patient in Figure 12 has tipped her head back until all lingual anatomical components become hidden from sight, thus proving the absence of incisal embrasures on the labial aspect.

Figure 13

Figure 14 A mandibular anterior dental restoration with an incorrectly placed incisal embrasure between the left central and lateral incisors, known as the “picket fence” appearance. A retracted view of the same patient reveals a two-unit, fixed, implant-supported restoration fabricated with great skill in many other aspects.

Figure 14

Figure 15 A mandibular anterior dental restoration with an incorrectly placed incisal embrasure between the left central and lateral incisors, known as the “picket fence” appearance. A retracted view of the same patient reveals a two-unit, fixed, implant-supported restoration fabricated with great skill in many other aspects.

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Figure 16 The patient presented with mandibular left central and lateral incisors with compromised root support in the region of the cementoenamel junction. The treatment plan was for splinted dental crowns.

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Figure 17 The final preparations.

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Figure 18 The block-carved steel band/acrylic provisional restorations.14 These restorations were carved easily, creating bilaterally symmetrical forms of equal width. No gingival embrasure was made on the labial aspect. Special attention to detail was given to the incisal edges, so they would match the adjacent teeth.

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Figure 19 Smile view of the provisional restorations.

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Figure 20 Diagram illustrating the natural anatomical position and progression of incisal embrasures on youthful, intact maxillary anterior teeth.

Figure 20

Figure 21 Full smile view and retracted view of a patient whose maxillary dentition displays a reverse incisal embrasure pattern and a concave, unattractive incisal edge line. The treatment plan was to place a new crown for the right lateral incisor, porcelain laminate veneers for the right canine and other incisors, and a porcelain laminate veneer to cover an existing porcelain-fused-to-metal abutment crown for the left canine.

Figure 21

Figure 22 Full smile view and retracted view of a patient whose maxillary dentition displays a reverse incisal embrasure pattern and a concave, unattractive incisal edge line. The treatment plan was to place a new crown for the right lateral incisor, porcelain laminate veneers for the right canine and other incisors, and a porcelain laminate veneer to cover an existing porcelain-fused-to-metal abutment crown for the left canine.

Figure 22

Figure 23 The final restorations were designed to recreate an embrasure form and flow as diagrammed in Figure 20. A convex incisal edge line was created (dental laboratory technology by Shin at Tanaka Dental, Skokie, IL).

Figure 23

Figure 24 The final restorations were designed to recreate an embrasure form and flow as diagrammed in Figure 20. A convex incisal edge line was created (dental laboratory technology by Shin at Tanaka Dental, Skokie, IL).

Figure 24