[Post-treatment changes of skeletal Class III morphology operated by orthognathic two-jaw surgery]

The purpose of this study was to investigate the dentofacial changes following orthognathic Two-jaw surgery in skeletal Class III patients. The materials consisted of cephalometric head films of 20 patients who had simultaneously undergone Le Fort I osteotomy and mandibular ramus osteotomy. All cases received the pre- and post-operative orthodontic treatment and had the observation periods over than one year after postoperative orthodontic treatment. The cephalometric radiographs were taken at following five stages: 1. Before preoperative orthodontic treatment, 2. Immediately before surgery, 3. After intermaxillary fixation, 4. After postoperative orthodontic treatment, and 5. Posttreatment observation period. The results were as follows: 1. The anteroposterior skeletal relapse was minimum after surgery. 2. The surgical manner of the maxillary vertical displacement did not effect the stability of the upper facial height after surgery. The lower facial height tended to decrease slightly during postoperative orthodontic treatment. 3. The upper and lower incisors showed lingual tipping during intermaxillary fixation, but the upper incisors tipped labially during retention period. In conclusions, Two-jaw surgery was considered to be quite effective for the correction of skeletal Class III malocclusions especially with the maxillary deficiency.