Postoperative relapse after mandibular setback surgery with perioperative counterclockwise rotation of the mandibular proximal segment

Objective. This study aimed to evaluate whether the perioperative counterclockwise rotation (ICCWR) of the proximal segment (IPS) can reduce relapse after mandibular setback surgery. Study Design. Patients who underwent less than 1 degrees of bilateral perioperative rotation of the PS were assigned to group I (n = 15). Group II (n = 14) included patients who showed greater than 1 degrees of perioperative CCWR bilaterally. To evaluate the PS rotation and the relapse, three-dimensional computed tomography (ICT) and lateral cephalography scans were analyzed. Results. Even with significantly different perioperative CCWR of the PS (.07 +/- .53 degrees vs -3.47 +/- 1.55 degrees), the relapse was not significantly different between group I (1.96 +/- 1.15 mm) and group II (1.81 +/- .92 mm). However, postoperative CCWR of the PS was significantly greater in group I. The relapse was not influenced by the amount of setback. Conclusions. A small degree of relapse is expected after mandibular setback surgery, even with perioperative CCWR of the PS.