Abstract
The purpose of this study was to evaluate changes of masticatory function in patients that underwent sagittal splitting mandibular ramus osteotomy from before operation to one year after operation.
The subjects were 21 patients with orthognathic deformities, and the control group consisted of 21 people with individual normal occlusion assessed as having normal orthognathic function without cross bite.
The following masticatory examinations were done: measurement of maximum mouth opening, width of active potential of masseter muscle, occlusal contact area, occlusal force, masticatory performance and masticatory score. All examinations were done in 21 patients before operation, and 1, 3, 6 and 12 months after operation. The mean values of these indices of the subject group were compared with those of the control group, and the mean values before operation were compared with the mean values for each period of examination in the patient group.
The result was that masticatory function following orthognathic surgery showed a decline at 1 month after surgery but gradually increased at 3 months. The values of maximum mouth opening, width of active potential in masseter muscle, masticatory performance and masticatory score at 12 months after surgery were all greater than those found before operation; the readings were almost the same as those for the control group. The values of occlusal contact area and occlusal force increased only to the presurgical level even at 12 months after surgery.
