Abstract
Mandibular retrusion results from abnormal positioning of the condylar head brought about by habitual occlusion. Pressure from muscles of the tongue and oral aperture make it difficult to achieve post-operative stability of the mandible head in orthognathic surgery. The purpose of this study was to evaluate the post-operative stability of the mandible under specific conditions.
We improved the operative method to be employed and controlled the mandibular position both before and after surgery.
The subjects consisted of 19 patients who underwent sagittal splitting ramus osteotomy. None of the subjects had asymmetry or open bite. Regarding surgical settings, we assumed the front teeth to be edge to edge andset the occlusion space in the first molar at approximately 1.5mm. The proximal segment was in contact with the distal segment, and a total of 3 lug s rews wereput into position. Surgical and post-operative changes were measured cephalometrically.
Radiographs were taken pre-operatively, at fixation, and then at 1, 3, 6 and 12 months after surgery. Ricketts analysis was used in tracing and analyzing the graphs (22 reference points).
One year following surgery, the mandibular body had rotated clockwise and was in a posterior direction. Over bite increased, and space closure between molars was complete at approximately 3 months after surgery.
Over-correction disappeared within 3 months of surgery.
The mandibular position stabilized suggesting that the new gnathic mandibular position and occlusion achieved would allow for improved function.
