The objective of this study was to define age-related changes in the human smile. The areas of interest were: upper lip length at smile and repose, upper lip thickness at smile and repose, maxillary incisal display at smile, interlabial gap height at smile,smile index, percent buccal corridors, intercommissural width at rest, smile height, and smile arc.Video equipment was used to capture video for 150 subjects. Two frames for each subject were selected; one frame representing the lips at rest and the second representing the widest smile. After excluding 50 subjects the data for the...