Soft and hard tissue changes after bimaxillary surgery in Japanese class III asymmetric patients

Abstract

Objectives:To assess the effects of bimaxillary surgery on Class III subjects with mandibular asymmetry, and to compare the effects of the type of surgery performed in the mandible on the facial profile especially in the presence of facial asymmetry.Materials and Methods:Thirty-six patients in whom imbalance between the maxilla and the mandible were corrected by Le Fort I osteotomy combined with bilateral intraoral vertical ramus osteotomy (BIVRO group, n=9), bilateral sagittal split ramus osteotomy (BSSRO group, n=14), or a combination of intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO) (IVRO + SSRO group, n=13). Cephalograms were taken before surgery (T1), and 1 year after surgery (T2). Hard and soft-tissue changes were compared.Results:The postsurgical findings showed that greater mandibular backward displacement and greater upper lip forward movement were more pronounced among BIVRO group when compared with BSSRO group. Upper lip relation to E-line showed greater improvement in BIVRO group than BSSRO and IVRO + SSRO groups. The ratios of corresponding mandibular soft to hard tissue movements were higher than that of maxillary movements and were more pronounced in IVRO + SSRO and BSSRO groups when compared with BIVRO group.Conclusion:IVRO surgical technique appears to be more effective in positioning the mandible more posteriorly and improving upper and lower lips position and competence.