Abstract
The purpose of this study is to clarify the morphological changes of mandibular symphysis in surgical orthodontic treatment and to investigate the factors involved.
The subjects consisted of fourteen mandibular prognathism patients who had undergone sagittal splitting ramus osteotomy. The radiographic cephalograms were taken before preoperative orthodontic treatment, before operation, immediately after operation, immediately after removal of intermaxillary fixation and immediately after postoperative orthodontic treatment.
Morphological changes of mandibular symphysis were longitudinally analyzed and the results were as f ollows.
1. The width of mandibular symphysis has decreased during the active treatment, especially during the intermaxillary fixation. During the intermaxillary fixation, elongation and lingual inclination of the mandibular incisors were found with the downward-backward (clockwise) rotation of the mandible and its relation to the decrease in the width of mandibular symphysis were also clarified.
2. The width of labioalveolar bone of the mandibar incisors has decreased during intermaxillary fixation and the correlation between its decrease and the decrease in periodontal bone height during the active treatment was found.
As the morphological changes of the mandibular symphysis were found in the surgical orthodontic treatment aforementioned, the treatment including the diagnosis and the postoperative observation, therefore, should be done in view of the periodontal problems as well.
