study was undertaken to investigate the effects of combined surgical orthodontic treatment on the mandibular movements and functional rehabilitation. Recordings of functional and border movements with sirognathograph unit(Bio-Pack. Bioresearch
Inc.
Wisconsin. U.S.A.) were obtained in 26dentofacial deformity patents, who were treated in the Department. Of Oral and Maxillofacial Surgery, Collge Dentistry, Kyung Hee University from April 1991 to July 1993, before surgery, after removal of
intermaxillary fixation, 6 and 12 months from the surgery.
To groupe the corelation of orthognathic surgery and mandibular movements, statistical analysis was performed by the operation methods (sagittal split ramus osteotomy and vertical ramus osteotomy) and the duration of intermaxillary fixation(IMF).
@ES The results were as follows.
@EN 1. The mandibular open-closing patterns in dentofacial deformity patients showed a even distribution of undeviated, cross over and noncross over form before and after mandibular setback surgery, but in the open-closing maximal effective width
and
lateral deviation, there was more noticeable tendency toward normalization and improvement, in vertical ramus osteotomy than sagittal split osteotomy group.
After mandibular setback surgery, the mandibular open-closing velocity patterns were significantly improved that, there was decrease in irregularity (from 38% to 15%), reduction of premature contact, and increase in maximal velocity(from
247.1mm/sec to
294.2mm/sec).
After mandibular setback surgery, the amount of maximal protrusion significantly increased from 6.8mm before to 8.1 mm 12 months after surgery and there showed better recovery rate in the sagittal split ramus osteotomy than in the vertical ramus
osteotomy group.
The amount of hinge and translatory movements after mandibular setback surgery showed relatively more decrease and more slow recovery in the vertical ramus osteotomy group.
The amount and angle of lateral movement after mandibular setback surgery were decreased immediately after IMF removal but recovered soon and significantly increased 12 months after surgery. There showed a good recovery tendency in the sagittal
split
ramus osteotomy and short IMF period group.
This general tendency can be interpreted as the result of normalization in dentofacial skeletal morphology through surgery with positive consequence in the function of the muscle and temporomandibular joint.
In the future, additional data, such as patient's temporomandibular disorder symptom, radiographic assesment of mandibular condyle, and the relationship between the condyle and disc, should be needed for definite analysis of mandibular movements
after
orthognathic surgery with systemic measurement of sirognathographic registration.
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