The esthetic zone of smile - Virtual Journal of Orthodontics

The vertical exposure of themaxillary incisors in relation to theupper lip at rest should be 2−4mm, and on smiling the entirecrown of the maxillary incisorsshould be exposed, with up to 1−2mm of associated gingiva. Aspontaneous smile, which isinvoluntary and expresses joyousemotion, tends to raise the upperlip slightly more than a posedsmile, which is voluntary .DENTO-GINGIVAL ANALYSISThe lips frame the teeth andgingiva. The gingiva frames theteeth. The ratio of tooth structureto the amount of gingival andlabial tissue should be harmonizedto prevent an over-dominance ofany one element. The verticalaspects of smile anatomy are thedegree of maxillary anterior toothdisplay (Morley ratio), upper lipdrape, and gingival display. In ayouthful smile, 75-100% of themaxillary central incisors should bepositioned below an imaginary linedrawn between the commissures.(fig 9)Fig 9 – a; acceptable morley ratiob; excessive display of incisorsOther factors to consider indesigning esthetic gingivalrelationships are: gingival line (therelationships of free gingivalmargins of the maxillary teeth),gingival scalloping and contour,papillary tip positioning, andgingival colorGingival Line and its ZenithThe key esthetic issue is that thegingival line for the anterior teethshould be relatively horizontal tothe horizon and relativelysymmetric on both sides of themidline. It may radiate up slightlyas it goes posterior. It is not criticalthat the lateral incisor gingival linefall incisal to the central as this isnot obvious when a person issmiling. Positioning the lateral tothe central incisor within 0.5 mmgingivally and 1 mm incisally isgenerally perceived as esthetic aslong as horizontal symmetry ismaintained. The contour of thegingival (ie, gingival scallop) to thetip of the papilla should bebetween 4 mm or 5mm and thetips of the papillae should have the20