Facial symmetry after distraction osteogenesis and orthodontic therapy.

The purpose of this study was to document changes in the facial symmetry of patients with severe hypoplastic mandibles treated with distraction osteogenesis and orthodontic therapy. Ten patients (5 males and 5 females), ages 7 to 22 years, underwent unilateral mandibular distraction osteogenesis with extraoral distracting devices. Orthodontic therapy was initiated after the completion of mandibular lengthening. The mean follow-up period was 25.5 months. Posteroanterior cephalograms were traced before distraction, 6 months after distraction, and at a later follow-up appointment. Displacement of the chin point (in millimeters) and the midpoint of the mandibular incisors, the piriform angle, the intergonial angle, the occlusal cant to the horizontal line (in degrees), the ratio of linear measurements (in millimeters) Co-Gn, Co-Go, and Go-Gn of the affected to the nonaffected side, CoA'-Mid to CoA-Mid, and GoA'-Mid to GoA-Mid were compared. At the latest follow-up appointment, patients defined as having a successful result had a mean occlusal cant of 1.25 degrees, an intergonial angle of 2.13 degrees, and a piriform angle of 2.63 degrees. The mean displacement of the chin point to the midline was 1.5 mm and that of the mandibular central incisors to the midvertical line was 1.38 mm. The results indicated improvement in all patients.