骨格型下顎前突症の顎矯正手術前後の下顎頭に関する研究

Abstract

Ninety mandibular prognathism patients were radiographically assessed for condylar position and clinically evaluated for temporomandibular joint (TMJ) function before and after orthognathic surgery. Forty-five of them underwent bilateral intraoral vertical ramus osteotomies (IVRO) with passive condylar seating and no interosseous fixation. Another 45 patients underwent bilateral sagittal split ramus osteotmies (SSRO) with anterosuperiorly directed condylar seating and titanium miniplate internal fixation. Changes in condylar position following surgical-orthodontic treatment were quantified using lateral oblique transcranial radiographs of the TMJ. Condylar position in the surgical group was compared to that derived from 20 controls with normal occlusion and asymptomatic TMJs.The following results were obtained:1. In the surgical group before treatment, condylar postion was more broadly distributed among various positions than in the control group. There was correlation between posterior condylar position and the presence of TMJ pain or noise.2. In the IVRO patients, the condyle exhibited significant anteroinferior displacement just after surgery. During the postoperative follow-up period, significant superoposterior movement of the condyles occurred.3. In the SSRO patients, the condyle showed significant anterior displacement just after surgery. During the postoperative follow-up period, a slight tendency for posterior condylar movement was observed.4. In the surgical group at the final postoperative follow-up, condylar position was similar to that in the control group. In addition, the incidence of the TMJ signs and symptoms was greatly reduced after orthognathic surgery.The results in this study suggest that surgical correction of mandibular prognathism can improve TMJ function by repositioning the condyle to a more stable and functional position.