Clinical Study of Intraoral Vertical Ramus Osteotomy

Part.1 Radiologic Study of Proximal Segments

Abstract

Intraoral Vertical Ramus Osteotomy (IVRO) is becoming widely used for correction of mandibular skeletal deformities in Japan.
The purpose of this study was to investigate the postoperative change of the proximal segments after bilateral IVRO. Retrospective radiographic assessments were performed for fifteen patients with mandibular prognathism who had been corrected surgically by bilateral IVRO
The results were as follows:
1. On lateral cephalometric analysis, the ramus inclination increased at one week after surgery and decreased gradually during one year.
2. On posteroanterior cephalometric analysis, Gonia showed lateral displacements at one week after surgery and returned internally during one year.
3. The condyles moved anteroinferiorly after surgery.