Long-Term Stability of Pre-Orthodontic Orthognathic Bimaxillary Surgery Using Intraoral Vertical Ramus Osteotomy Versus Conventional Surgery

Abstract

The aim of the present study was to compare the long-term stability of bimaxillary surgery using an intraoral vertical ramus osteotomy (IVRO) with and without presurgical orthodontic treatment. The present retrospective study included 31 consecutive patients with skeletal Class III malocclusions who had undergone bimaxillary surgery (Le Fort I osteotomy and bilateral IVRO). Patients were divided into 2 groups based on treatment type: pre-orthodontic orthognathic surgery (POGS; n=17) and conventional surgery with presurgical orthodontic treatment (CS; n=14). Lateral cephalograms were obtained before surgery, 1day after surgery, 1month after surgery, 1year after surgery, and 2years after surgery to evaluate skeletal and soft tissue changes between the 2 groups. Data were analyzed using χ2 tests, Mann-Whitney U tests, repeated-measures analyses of variance, and independent t tests. There was no significant difference in skeletal or soft tissue measurements-with the exception of the angle between the sella-and-nasion plane and the occlusal plane (SN-OP; P<.001)-between the CS and POGS groups at 2years after IVRO. The SN-OP had increased in the CS group but decreased in the POGS group at 2years after surgery. These findings suggest that POGS and CS have similar long-term stability in patients with skeletal Class III malocclusion.