Angular asymmetries of the human face

Purpose: The determination of an acceptable occlusal plane is essential for the development of esthetic prosthodontic restorations. However, since mos t faces are not symmetric, a method was developed for measuring facial angu lar asymmetry, ie, the divergence from the vertical or horizontal of the li ne joining the midpoint of the intercanthal line and the philtrum of the li p, the interpupillary line, the intermeatal line, the lip commissure line, and the intercuspid line. Materials and Methods: Standardized frontal image s (mouth closed, smiling, and biting on a wooden spatula) of 100 subjects w ere taken using a digital camera. These images were downloaded into a compu ter, and the angles between the various facial lines and the horizontal wer e measured. The subjects were grouped by sex, age, and history of trauma an d orthodontic treatment. Results: No statistically significant differences were found between the mean values for each group. Conclusion: Asymmetry of the face can be measured using digital camera imaging and computer analysi s. A range of facial asymmetries that can influence the choice of occlusal plane during prosthodontic treatment exists. Thus, the use of an occlusal p lane parallel to the ala tragus and interpupillary lines, as often advocate d by prosthodontists, may result in less than ideal esthetics in the final restoration.