Postoperative stability for surgery-first approach using intraoral vertical ramus osteotomy: 12 month follow-up.

The aim of this study was to evaluate the postoperative stability of the surgery-first approach using intraoral vertical ramus osteotomy (IVRO). We retrospectively studied a sample derived from the patients who were treated by the surgery-first approach using a LeFort I osteotomy and IVRO for correction of class III dentofacial deformity from 2008 to 2012. Lateral cephalograms taken preoperatively and 2 days, 6 months, and 12 months postoperatively were traced, and the skeletal and dental variables at different time points were analysed. The study sample comprised 37 subjects, mean (SD) age 23 (4) years. The mean (SD) total duration of treatment including postoperative orthodontics was 14 (6) months, and surgical movement of the maxillary A point was 0.75 (1.3)mm anteriorly, and 0.21 (1.79)mm superiorly. The surgical change in the position of the maxillary first molar was 1.01 (1.57)mm superiorly. The mean (SD) movement of mandible was 11.15 (5.4)mm posteriorly at pogonion and 1.02 (1.79)mm inferiorly at menton. There were no significant change in maxillary skeletal variables during the first year postoperative period. The surgical relapse of mandible at pogonion was 0.63 (2.31) mm anteriorly (p=0.01), however, the relapse in superior direction at menton was 2.86 (1.39) mm with statistical significance (p=0.01). The total duration of orthodontic treatment with surgery-first was roughly 5 months shorter than conventional preoperative and postoperative orthodontic treatment. The surgery-first approach using IVRO is effective and predictable, and shortens the overall duration of treatment. Anterior relapse of the mandible was less than 1mm, and increased superior relapse can be compensated for with appropriate preoperative planning to provide a reliable outcome. This study was limited to 12 months' follow-up, and a long term follow-up study is indicated.