Laterality of the Human Face

Objectives: We investigated if there was any specificity in the frequency as well as the site and the direction of facial asymmetry and if there was any difference of laterality of the face according to sex, age, and skeletal patterns@in orthodontic patients. Methods: A total of 1600 Japanese who had visited the university dental hospital and received orthodontic examinations were selected. Conventional facial photos (frontal views in 35mm color reversal films) of the patients were recorded with the heads fixed by ear rods and the Frankfort horizontal plane parallel with the ground and digitized. The facial midline was defined as a perpendicular bisector between the bilateral center of the pupils. The intersecting point of the facial contour and the ear rod was defined as po. Midfacial widths (po to the facial midline) and the length of the facial contour (po to menton) of the hemiface were measured. The samples were categorized into 18 groups@by sex, age, and skeletal patterns. Results: The length of the right side midfacial width was greater than the left side for all groups (P<0.0001). The right side length of the facial contour was longer than the left side (P<0.0001). Sexual specificity, age difference, and difference by skeletal patterns were not significant. Conclusion: The results suggest obvious@dominancy in size of the right side hemiface.