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ePaper created 2015-05-14, 11:05:01 | version 1.38.0
I special _ smile analysis and smile design _Dentogingival aesthetics Gingival margin placement and the scalloped shape, in particular, are well discussed in the litera- ture. As gingival heights are measured, heights rela- tivetothecentralincisor,lateralincisor,andcaninein an up/down/up relationship are considered aesthetic (Fig. 6). However, this may create a false perception thatthelateralgingivallineisincisaltothecentralin- cisor. Rather, in most aesthetic tooth relationships, the gingival line of the four incisors is approximately the same line (Fig. 6), with the lateral incisor perhaps being slightly incisal.7 The gingival line should be rel- atively parallel to the horizon for the central incisors andthelateralincisorsandsymmetriconeachsideof the midline.2,8 The gingival contours (i.e., gingival scallop) should follow a radiating arch similar to the incisal line. The gingival scallop shapes the teeth and should be between 4mm and 5mm (Fig. 7).9 Related to normal gingival form is midline place- ment. Although usually the first issue addressed in smiledesign,itisnotassignificantastoothform,gin- gival form, tooth shape, or smile line. Severalrulescanbeappliedwhenconsideringmod- ifyingthemidlinetocreateanaestheticsmiledesign: _The midline only should be moved to establish an aesthetic intra- and inter-tooth relationship, with the two central incisors being most important. _Themidlineonlyshouldbemovedrestorativelyupto therootoftheadjacenttooth.Ifthemidlineiswithin 4mmofthecentreoftheface,itwillbeaesthetically pleasing. _Themidlineshouldbeverticalwhentheheadisinthe postural rest position. _Evaluating dental aesthetics Part of evaluating dental aesthetics for smile de- sign is choosing tooth shapes for patients based on their facial characteristics (e.g., long and dolicho- cephalic, or squarish and brachycephalic). When pa- tients present with a longer face, a more rectangular tooth within the aesthetic range is appropriate. For someone with a square face, a tooth with an 80% width-to-length ratio would be more appropriate. Fig. 4_Evaluating the maxillary incisal edge position is the starting point for establishing oral aesthetics. Fig. 5_According to the 4.2.2 rule, this patient’s smile is deficient in aesthetic elements, having only 1mm of tooth display at rest (left), minus 3mm of gingival display, and 4mm of space between the incisal edge and the lower lip (right). Fig. 6_Gingival symmetry in relation to the central incisors, lateral incisors and canines is essential to aesthet- ics. Optimal aesthetics is achieved when the gingival line is relatively horizontal and symmetrical on both sides of the midline in relation to the central incisors and lateral incisors. Fig. 7_The aesthetic ideal from the gingival scallop to the tip of the papilla is 4–5mm. 12 I CAD/CAM 2_2015 Fig. 4 Fig. 5 Fig. 6 Fig. 7