Stability Following Intraoral Vertico-Sagittal Ramus Osteotomy and Sagittal Split Ramus Osteotomy for Asymmetric Mandibular Prognathism

Objective: The purposes of this study were to clarify differences in skeletal stability and to compare transverse and sagittal angulations of the proximal segment following correction of asymmetric mandibular prognathism using intraoral vertico-sagittal ramus osteotomy (IVSRO) and sagittal split ramus osteotomy (SSRO) procedures. Methods: Fifteen patients with mandibular protrusion and deviation were enrolled in this study, with IVSRO in seven and SSRO in eight. Lateral and posteroanterior cephalograms obtained before surgery (T0), within four weeks of surgery (T1), and at least 10 months after surgery (T2) were analyzed and angular measurements obtained at these time points were compared. Results: No significant differences in vertical and horizontal movements of point B and the menton were observed between the IVSRO and SSRO groups. Intergonial width increased significantly from T0 to T1 in the IVSRO group. Conclusions: IVSRO and SSRO conferred good postoperative stability when used to correct mandibular protrusion and deviation. Although IVSRO led to an initial increase in intergonial width, this gradually decreased within approximately 10 months after surgery.