Surgical-orthodontic correction of mandibular deficiency: five-year follow-up.

Changes in dental and skeletal relationships at 5 years postsurgery were evaluated in a group of 35 patients whose mandibular deficiency had been corrected by the same surgeon, using sagittal split osteotomy of the mandibular ramus. From 1 to 5 years postsurgery, there was a small (0.9-mm) but statistically significant mean decrease in mandibular length (condylion to point B). In six patients, the decrease in mandibular length was 2 to 4 mm, and in two it was more than 4 mm, but only one of these individuals had more than a 2-mm increase in overjet. There was no mean change in overjet, but three patients had a 2 to 4-mm increase. Of these, one had 3.2 mm shortening of the mandible, one had 1.4 mm shortening of the mandible, and one had no change in mandibular length but repositioning of the incisors. Most patients had a deep overbite initially, and there was a tendency for the bite to deepen between the first and fifth years postoperatively, more as a result of extrusion of incisors than of mandibular rotation. Remodeling of the gonial angle area, with vertical and/or horizontal repositioning of gonion, was noted in more than half the subjects. It appears that morphologic changes related to continued skeletal remodeling, often compensated for by small changes in mandibular posture or tooth positions, continue after 1 year postsurgery for many patients.