Skeletal Relapse After Mandibular Setback in Bi Max Surgery: Intraoral Vertical Ramus versus Bilateral Sagittal Split Osteotomies
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.
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.
The percentage of horizontal relapse after IVRO without fixation is equal to that after BSSO with semi rigid internal fixation.