The Evaluation of the Positional Change of the Mandibular Condyle after Bilateral Sagittal Split Ramus Osteotomy using Three Dimensional Computed Tomography in Skeletal Class Iii Patients

Jang, Jung Rok; Choi, Guen Ho; Park, Young Jun; Kim, Bang Sin; Yu, Min Gi; Kook, Min Suk; Park, Hong Ju; Ryu, Sun Youl; Oh, Hee Kyun

Abstract

PURPOSE
This study was performed to evaluate three-dimensional positional change of the condyle using 3D CT after bilateral sagittal split ramus osteotomy (BSSRO) in skeletal class III patients.
PATIENTS AND METHODS
Nine patients who underwent BSSRO for mandibular set-back in skeletal class III malocclusion without facial asymmetry were examined. Miniplates were used for the fixation after BSSRO. 3-D CT was taken before, immediately after, and 6 months after undergoing BSSRO. After creating 3D-CT images using V-works 4.0(TM) program, axial plane, coronal plane, < sagittal plane were configured. Three dimensional positional change, from each plane to the condyle, of the nine patients was measured before, immediately after, and 6 months after undergoing BSSRO.
RESULTS
1. The mean value of mandibular set-back for nine mandibular prognathism patients was 7.36 mm (+/- 2.42 mm). 2. In the axial view, condyle is rotated inward immediately after BSSRO (p < 0.05), comparing with preoperative but outward 6 months after BSSRO comparing with postoperative (p < 0.05). 3. In the axial view, condyle is moved laterally immediately after BSSRO (p < 0.05), comparing with preoperative but regressed 6 months after BSSRO comparing with preoperative (p < 0.05). 4. In the frontal < coronal view, there is changed immediately after and 6 months after BSSRO, comparing with preoperative but no statistical difference.
CONCLUSION
These results indicate that three-dimensional positional change of the condyle in skeletal class III patients is observed lateral displacement < inward rotation immediate after BSSRO, but the condyle in 6 months after BSSRO tends to regress to preoperative position.