下顎頭に骨変化を有する骨格性Ⅱ級患者の顎矯正手術後の咬合の安定性に対する手術時の下顎骨片移動位置の検討

osseous changes of the condyle of the temporomandibular joint

北海道歯学会

北海道歯学雑誌

This study evaluates whether mandibular proximal and distal segment positions during orthognathic surgery affect the stability of surgical orthodontic treatment in skeletal Class II orthodontic patients with osseous changes of the mandibular condyle of the temporomandibular joint (TMJ). 　Eight Japanese women with Class II malocclusion with osseous changes of the mandibular condyle were examined. All cases underwent double-jaw surgery. Panoramic radiographs at pre- and posttreatment were used to evaluate osseous changes of the mandibular condyle of the TMJ. Lateral cephalograms at pretreatment, just after double-jaw surgery, and posttreatment were used to evaluate changes in mandibular proxi mal and distal segment positions during double-jaw surgery. Further, osseous changes of the mandibular condyle were observed in four cases (unstable group). Compared with the other four cases (stable group), counterclockwise rotation of the distal segment of the mandible was not shown in the unstable group. Counterclockwise rotation of the mesial segment was shown in both groups. Consequently, the gonial angle was increased after double-jaw surgery in the unstable group. Unstable occlusion in skeletal Class II patients with osseous c hanges of the TMJ condyle was attributable to further osseous changes of the TMJ condyle. Moreover, mandibular proximal and distal segment positions during orthognathic surgery may affect subsequent osseous changes of the TMJ condyle.