Condylar Movement in Patient with Skeletal Mandibular Prognathism during Maximum Opening and Closing Movement before and after Surgery

Condylar movement of patients with mandibular prognathism who received sagittal splitting ramus osteotomy (SSRO) was investigated using computer aided diagnostic axiography (CADIAX) . Linear and angular parameters were used to evaluate the maximum opening and closing paths of the condyle projected on the sagittal plane. The motion paths of six subjects with mandibular prognathism (MP group) were examined immediately before surgery and during the retention period. The results were compared with the recording from six normal subjects (control group) . The results were as follows : (1) The average change in the maximum translating distance of the condyle in the retention period was 99.4±14.5% of the presurgical value on right side and 97.8±20.8% on the left side. The difference was not significant. (2) The shape of the opening translating curve of the MP group was flatter than that of the control group, however, no significant differences were found between the pre-and postsurgical curves of the MP group. (3) The coordination between the maximum opening and closing paths of the control group was fairly stable and smooth. However, although some improvement was observed, the paths of the MP group were unstable even after surgical treatment and large individual variations were observed.