ABSTRACT
Mandibular prognathism is one of the most common skeletal disorders in Iranian population and so mandibular setback surgery is one of the most common surgeries in Oral and Mxilllofacial area. Ramus sagittal osteotomy is one of the surgeries which is done for the purpose of mandibular setback or advancement. The purpose of this study was to evaluate the progress of maximum mouth opening [MMO] after bilateral sagittal split osteotomy [BSSO] surgery in patients with mandibular prognathism. In this study, 36 patient's undergone BSSO surgery with Hunsck technique in order to correct manibular prognathism were taken into consideration. In all patients, fixation was done with three titanium screw in each side. Maximum mouth opening was measured before surgery and within 1, 3, 6 months after surgery. Repeated measurement was performed for data analysis [alpha = 0.05]. In the patients 81.32% of maximum mouth opening was gained after one mouth, 92.1/5 after three months and nearly total recovery [98.94%] after 6 months of surgery. The results confirm the concept that limitation in MMO is not a long lasting complication in bilateral sagittal split osteotomy surgery in patients with mandibular prognathism and it would approximatey be as same as before surgery after six months