Smile Symmetry

Facial and smile symmetry is generally considered to increased perceived esthetics."^50,51The static symmetry of individual components of the smile, including tooth size and gingival contours, and the dynamic symmetry of lip movement during smiling and speaking contribute to overall esthetic perception.⁵² A difference in lateral incisor width of > 1mm between contralateral teeth was judged to be unesthetic by both dentists and laypersons. However, when the width of both lateral incisors was altered by that amount, the reduction is esthetics was not judged as harshly by either group.⁵³ Negative esthetic assessment is also associated with unilateral differences in the relative vertical positioning of the corners of the mouth during full smile, which can be related to variations in facial musculature of partial facial paralysis.^54,54 Furthermore, an oblique commissural line that is off-parallel with the interpupillary line, can reduce perceived esthetics and may give the illusion of skeletal asymmetry and/or a transverse cant of the maxilla.¹⁶