Evaluation of bone formation after sagittal split ramus osteotomy with bent plate fixation using computed tomography.

摘要

PURPOSE: To evaluate bone formation between the proximal and distal segments after a sagittal split ramus osteotomy (SSRO) with bent plate fixation. PATIENTS AND METHODS: The subjects were 23 patients (46 sides) who underwent bilateral SSRO setback surgery. They were divided into titanium and absorbable plate groups. A 3 to 7-mm gap was made between the proximal and distal segments and a bent plate was fixed with 4 screws in each side of the mandible. The square of ramus (RmS), the anteroposterior length (RmA-RmP), and the mediolateral width (RmM-RmL) of the ramus at the horizontal plane under the mandibular foramen were assessed preoperatively, immediately after surgery, and 1 year postoperatively by computed tomography (CT). RESULTS: There were no significant differences between the titanium and absorbable plate groups over time. RmS after 1 year was larger than preoperatively in both groups (P < .0001). RmA-RmP significantly increased immediately after surgery and significantly decreased after 1 year in both groups (P < .0001). RmA-RmP after 1 year was significantly larger than the preoperative value in both groups (P < .0001). RmM-RmL showed a similar tendency to the anteroposterior length, but was not significant. CONCLUSIONS: The gap between the proximal and distal segments can fill with new bone after SSRO with both titanium and absorbable plates, even with few bony contacts between segments.