Horizontal changes of the proximal mandibular segment after mandibular setback surgery using 3-dimensional computed tomography data
To evaluate horizontal changes of the proximal mandibular segment after mandibular setback surgery using 3-dimensional computed tomography (3-D CT).Study Design.
This study included 66 patients who underwent bilateral sagittal split ramus osteotomy for correction of mandibular prognathism. With the use of 3-D CT data obtained preoperatively (T1), immediately postoperatively (T2), and 6 months postoperatively (T3), horizontal changes of the proximal mandibular segment, including the intercondylar width, the intergonial width, and the frontal–ramal inclination were evaluated.Results.
The value of the right frontal–ramal inclination was 11.43 ± 1.36° at T1, 11.91 ± 1.96° at T2, and 10.7 ± 1.5° at T3. The values of the left frontal–ramal inclination were 6.10 ± 1.03° at T1, 8.17 ± 1.66° at T2, and 7.66 ± 1.65° at T3. The values of the intergonial width were 99.67 ± 1.67 mm at T1, 98.24 ± 1.72 mm at T2, and 97.08 ± 1.71 mm at T3. The intergonial width was significantly decreased at T3 compared with T1 (P < .001). The values of the intercondylar width were 123.51 ± 1.66 mm at T1, 123.9 ± 1.66 mm at T2, and 122.88 ± 1.58 mm at T3.Conclusions.
Lower facial width at mandibular angle region decreased immediately after mandibular setback surgery and showed further decreases during the postoperative period.