Three Dimensional Evaluation of Changes in Mandibular Condyle Position After Orthognathic Surgery

Abstract Background: This study aims to examine the changes in both mandibular condyle positions before and after surgery to evaluate manual temporomandibular joint (TMJ) positioning procedure after bilateral sagittal split ramus osteotomy in adult patients diagnosed with mandibular prognathism and compare them with the studies in the literature.Methods: Patients diagnosed with mandibular prognathism, including bilateral sagittal split ramus osteotomy (BSSRO) procedures, in addition to their orthodontic treatment, were examined. The study including the examination of 88 right and left mandibular condyles of 44 patients, 24 male and 20 female. This study focused on comparing retrospectively obtained cone-beam computed tomography data of patients for 1-2 weeks before surgery (T0) and a mean of six months postoperatively (T1). DICOM formats of cone-beam computed tomography data were analyzed in the 3D Slicer software program, considering the references of Choi et al.. The examination was made separately in the axial, sagittal and coronal planes. IBM® SPSS® Statistics was used for statistical analysis. After testing the homogeneity of variance and normality, the dependent sample t-test was applied at a 95% significance level.Results: The left mandibular condyle head rotated inward in the axial plane, but the change in the right condyle head was not statistically significant. In the sagittal plane, there was no significant change of both mandibular condyle heads. In the coronal plane, the right mandibular condyle head showed outward rotation, but the change in the left condyle head was not statistically significant. In addition, there was no statistically significant difference in the distance between the most medial points of the mandibular condyle heads in the coronal plane.Conclusions: The sagittal plane’s changes of the condyles can be maintained as before the surgery with manual positioning in bilateral sagittal split ramus osteotomy procedures. Inward and outward rotations seen in the axial and coronal planes are also consistent with the literature review. Stress occurring between the segments in the fixation process, operator positions during the operation, the direction and amount of the force applied for fixation, and contacts or gaps between the proximal and distal segments may be caused.