This study was undertaken to investigate the effect of orthognathic surgery on occlusal force. The maximum bite force was measured in 26 dentofacial deformity patients, aged 14-26 (mean age 20.3) years, before surgery and at IMF removal, 3, 6 and
12months postsurgery. To grope the correlation of bite force and skeletal change after orthognathic surgey, the cephalometric headplates were measured, tabulated and statistically analyzed.
@ES The results were as follows.
@EN 1. The presurgical maximum bite force was 13.7kg in upper first molar (rt, side 12.7kg, lt. side 14.6kg). There was remarkable difference with that of normal occlusion.
2. The recovery of bite force was verey significant in according to the operation method and the duration of IMF that was 7.6kg at EMF remoual, 14.2kg at 3 months, 19.7kg at 6 months. 26.1kg at 12 months postsurgery.
3. To fasten the recovery and to increase the bite force after orthognathic surgery, the long IMF time and the injury to the masticatory muscle should be avoided by the internal rigid fixation and early physical exercise.
4. The bite force was positively correlated to the changes of mandibular plane angle, the angle between platatal plane and mandibualr ane, the angle between occlusal plane and mandibular plane, and negatively correated to the changes of
mandibular
body
length in craniofacial structure.
5. There was no correlationship between bite for5ce and mesial inclination of tooth long axis of first molar in this subject.
6. There was no correlation between the changes of bite force and the changes of mechanical advantage of the temporal and masseter muscle.
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