Figure 3.

Twenty-two landmarks were defined. Point 1, midpoint of philtrum; point 2, lowest point of the lower edge of the upper lip; point 3, incisal edge of the maxillary central incisor (if the lower lip contacted the upper central incisor when smiling, marking the lowest contact point as landmark 3); points 4, 5, 6, 7, 8, intersection points of the upper long axis of the incisors and the incisor edge and the canine cusp, respectively; points 9, 10, 11, 12, 13, 14, gingival zenith (GZ) of upper anterior teeth; point 15, the most incisal point of the upper central incisors contact area; point 16, centre of the upper edge of the lower lip, corresponding to point 15; points 17 and 18, points corresponding vertically to points 5 and 7 on the upper edge of the lower lip; point 19, interdental papilla tip of the upper central incisors; point 20, apex of the upper central incisors contact area; point 21, the most outstanding point on the gingival margin equivalent to the line linking points 12 and 22; point 22, the point corresponding to point 12 on the boundary between free gingiva and attached gingiva.