Skeletal Relapse After Mandibular Setback in Bi Max Surgery: Intraoral Vertical Ramus versus Bilateral Sagittal Split Osteotomies

Abstract

Objectives: This study aimed to measure and compare the postoperative horizontal and vertical changes (relapse) that occur at B point and pogonion after intraoral vertical ramus osteotomy (IVRO) without fixation and bilateral sagittal split osteotomy (BSSO) with semi rigid internal fixation in bimax surgery. Materials and Methods: Eleven patients with skeletal class III malocclusion mandibular prognathism and maxillary hypoplasia were chosen. Six cases underwent BSSO; and five IVRO. All patients underwent Lefort I osteotomy without genioplasty. Result: Postoperative changes (relapse) of B-point and pogonion in horizontal and vertical axes from 1 week post operatively (T0) to 1 year post operatively (T2) were assessed and the percentage of relapse of each point and each axis was compared. It was noted that the horizontal relapse in IVRO was 27.7 % at B point and 40.6 % at pogonion while, in BSSO group it was noted that the horizontal relapse was 28.1 % at B point and a greater number i.e., 40.9 % at pogonion. Conclusion: The percentage of horizontal relapse after IVRO without fixation is equal to that after BSSO with semi rigid internal fixation.