The most frequently used techniques for correcting skeletal Class III deformity are sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO). The purpose of this study was to compare the clinical outcome including skeletal stability after SSRO with semirigid fixation and IVRO. The subjects of this study were 23 patients who underwent SSRO for mandibular setback with semirigid fixation by titanium miniplate and 20 patients who underwent IVRO for mandibular setback without interosseous fixation. The mean period of maxillo-mandibular fixation was 5.1 days in the SSRO group and 7.3 days in the IVRO group. The evaluation items were skeletal changes, operation time, blood loss, sensory disturbance, temporomandibular joint (TMJ) sound and mandibular range of motion (ROM). Compared with the SSRO group, the B-point and pogonion moved significantly posteriorly in the IVRO at more than 6 months after surgery. Operation time, blood loss and occurrence of sensory disturbance were also less than those in the SSRO group. There were no significant differences in TMJ sound and ROM. The results of this study showed that both methods had minimal relapse and no significant difference in comparison by measurement of B-point and pogonion. In conclusion, both methods are effective for correcting skeletal Class III malocclusion, and the surgical method should be selected in consideration of each clinical distinction.
