Stability of mandibular constriction with a symphyseal osteotomy.

The purposes of this study are to determine the stability of surgical mandibular constriction with a midline osteotomy and to evaluate the periodontal and temporomandibular joint responses. A symphyseal osteotomy to facilitate mandibular construction was performed in 15 patients to correct transverse discrepancies. At the same time a surgical anterior or posterior repositioning of the mandible was done by using a bilateral sagittal osteotomy of the vertical ramus. Tomograms in the coronal plane including the mandibular second molars were taken preoperatively (T1), immediately postoperatively (T2) and 8 weeks postoperatively (T3). Linear measurements between the cortical borders of the mandible were assessed from the tomograms at each time period. Median surgical and postoperative changes in mandibular width were determined. When evaluating the entire group no statistically significant change in the surgical constriction was found postoperatively (T2 and T3), although there was some individual variability. An examination of the periodontal response at the osteotomy site revealed no statistically significant change between the initial and the 5-month postoperative examinations. No changes in joint noise were detected postoperatively, and all mandibular joint movements returned to preoperative values except for excursive movements. Mandibular constriction with a midline osteotomy on conjunction with a bilateral sagittal osteotomy was found to be a stable modality for correcting transverse disharmonies.