RESUMEN
BACKGROUND: Mandibular setback for the treatment of mandibular prognathism is a common orthogenetic surgical procedure carried out using various intraoral and extraoral methods. Reduced mandibular movement range (MMR) is one of the common complications of this surgery. OBJECTIVES: The aim of this study was to compare the reduction of MMR after 3 surgical procedures including sagittal split osteotomy (SSO), intraoral vertical ramus osteotomy (IVRO), extraoral vertical ramus osteotomy (EVRO). METHODS: In this clinical trial, 150 patients with mandibular prognathism were divided into 3 groups of 50 patients. In the first group, mandibular setback was performed using SSO; in the second group, we used IVRO, and EVRO was the method used in the third group. In each group, before and 3 months after the surgery, maximum interincisal opening and the range of right and left lateral and protrusive movements were measured and compared. RESULTS: Although the mean amount of MMR reduced in all the groups, it was not equal in all the groups. Sagittal split osteotomy and the EVRO resulted in the most and least reduction of MMR, respectively. CONCLUSIONS: Reduced MMR is one of the complications of SSO, IVRO, and EVRO; however, SSO resulted in the most and EVRO in the least effect on limitation of movement after surgery.