The Gingival Interface

An esthetically successful pontic will replicate the form, contours, incisal edge, gingival and incisal embrasures, and color of adjacent teeth. The pontic's simulation of a natural tooth is most often betrayed at the tissue-pontic interface. The greatest challenge here is to compensate for anatomic changes that occur after extraction. Special attention should be paid to the contour of the labial surface as it approaches the pontic-tissue junction to achieve a "natural" appearance. This cannot be accomplished by merely duplicating the facial contour of the missing tooth, because after a tooth is removed, the alveolar bone undergoes resorption and/or remodeling. If the original tooth contour were followed, the pontic would look unnaturally long incisogingi-vally (Fig. 20-32). To achieve the illusion of a natural tooth, an esthetic pontic must deceive observers into believing they are seeing a natural tooth.

The modified ridge-lap pontic is recommended for most anterior situations; it compensates for lost buccolingual width in the residual ridge by overlapping what remains. Rather than emerging from the crest of the ridge as a natural tooth would, the cervical aspect of the pontic sits in front of the ridge, covering any abnormal ridge morphology resulting from tooth loss. Fortunately, because most teeth are viewed from only two dimensions, this relationship remains undetected. A properly de

Lateral Incisor Recessed

Fig. 20-32. Correct incisogingival height is critical to esthetic pontic design. A, Esthetic failure of a four-unit FPD replacing the right central and lateral incisors. The pontics have been shaped to follow the facial contour of the missing teeth, but because of bone loss they look too long.

B, The replacement FPD. Note that the gingival half of each pontic has been reduced. Esthetics is much improved.

C, This esthetic failure is the result of excessive reduction. The central incisor pontics look too short.

Fig. 20-32. Correct incisogingival height is critical to esthetic pontic design. A, Esthetic failure of a four-unit FPD replacing the right central and lateral incisors. The pontics have been shaped to follow the facial contour of the missing teeth, but because of bone loss they look too long.

B, The replacement FPD. Note that the gingival half of each pontic has been reduced. Esthetics is much improved.

C, This esthetic failure is the result of excessive reduction. The central incisor pontics look too short.

signed, modified ridge-lap provides the required convexity on the tissue side, with smooth and open embrasures on the lingual side for ease of cleaning. This is difficult to accomplish. Clinically, many pontics are seen with less than optimal contour, resulting in an unnatural appearance. This can be avoided with careful preparation at the diagnostic waxing stage (see Chapter 3). Sometimes the ridge tissue must be surgically reshaped to enhance the result.

In normal situations, light falls from above, and an object's shadow is below it. Unexpected lighting or unexpectedly placed shadows (Fig. 20-33) can be confusing to the brain. Because of past experience, the brain "knows" that a tooth grows out of the gingiva, and it therefore "sees" a pontic as a tooth unless telltale shadows suggest otherwise. Special care must be taken when studying where shadows fall around natural teeth, particularly around the gingival margin. If a pontic is poorly adapted to the residual ridge, there will be an unnatural shadow in the cervical area that looks odd and spoils the illu-

Gingival Margin

Fig. 20-33. Optical illusion. A and B are identical except that one image is upside down. Most people make different three-dimensional interpretations of each photograph, interpreting one as a negative impression and the other as a positive cast. (Verify the illusion by turning the book.) The interpretation is based on how shadows fall; in normal situations, objects are seen illuminated from above.

Fig. 20-33. Optical illusion. A and B are identical except that one image is upside down. Most people make different three-dimensional interpretations of each photograph, interpreting one as a negative impression and the other as a positive cast. (Verify the illusion by turning the book.) The interpretation is based on how shadows fall; in normal situations, objects are seen illuminated from above.

sion of a natural tooth (Fig. 20-34). In additional, recesses occurring at the gingival interface will collect food debris, further betraying the illusion of a nat-uraltooth.

When appearance is of utmost concern, the ovate pontic, used in conjunction with alveolar preservation or soft tissue ridge augmentation, can provide an appearance at the gingival interface that is virtually indistinguishable from a natural tooth. Because it emerges from a soft tissue recess, this pontic is not susceptible to many of the esthetic pitfalls previously described for the modified ridge lap pontic. However, in most cases, the patient must be willing to undergo the additional surgical procedures that an ovate pontic requires.

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