Objective. The purpose of the present study was to investigate the improvements of facial profile and postoperative stability by single mandibular setback surgery. Materials and Methods. The study included twenty-seven patients who underwent mandibular prognathism correction by sagittal split ramus osteotomy (SSRO). Cephalometric radiograms (lateral and frontal) were collected and analyzed at three intervals: preoperatively (T1), immediately postoperatively (T2), and final follow-up postoperatively (T3). The lateral and frontal cephalometric parameters were measured. The immediate postoperative change (T21), postoperative stability (T32), and final surgical change (T31) were calculated and analyzed. The null hypothesis is that postoperative stability (T32) was not significantly correlated to amount of mandibular setback (T21). Results. The immediate postoperative change (T21) of menton (Me) was significantly backward 8.7 mm. In the final postoperative change (T31), average chin points anterior movements were approximately 0.32 mm. Investigating frontal appearance, inter ramus posterior (InterRp) and intergonion (InterGo) widths were significantly increased with 1.8 and 2.2 mm, respectively. Bilateral ramus angles were not significantly increased, about 1°. The horizontal Me (T32) had significant correlation (p=0.028) with amount of setback (T21). Therefore, null hypothesis is rejected. Conclusion. Postoperative relapse was significantly correlated to the amount of setback. The frontal transverse changes (InterRp and InterGo) were significantly increased.
Long-term Stability after Bilateral Sagittal Split Ramus Osteotomy for Mandibular Prognathism Patients with Open Bite
