The prevalence of facial asymmetry in the dentofacial deformities population at the University of North Carolina.

In a retrospective survey of 1,460 patients evaluated in the Dentofacial Clinic at the University of North Carolina, 495 (34%) were found to have clinically apparent facial asymmetry. When present, asymmetry affected the upper face in only 5% (n = 23), the midface (primarily the nose) in 36% (n = 178), and the chin in 74% (n = 365). The occlusal plane was canted, indicating vertical asymmetry, in 41% (n = 201). Patients with Class II problems, whether or not due to mandibular deficiency, had a 28% prevalence of asymmetry; those with other types of problems (e.g., Class III, long face, Class I) had a 40% prevalence, which is significantly higher than those with Class II occlusions. When the chin deviated transversely, there was an 80% chance that the deviation was to the left. Only in patients with long face was there an equal distribution of left-right chin asymmetry. In the other groups, the prevalence of deviation of the chin to the left approached 90%. These findings are meaningful for clinicians because asymmetry must be identified and planned for prior to initiating treatment.