ABSTRACT
The condyle head of mandible was usually influenced by the stressful forces generated from a voluntary movement of bone fragment after the sagittal ramus osteotomy which would be mainly performed for the mandibular deformity patient. In this study we measured the stress values exerted on condyle and evaluated which area of condyle had a more stress concentration while condyle head moved in X, Y and Z axis by using a 3 dimensional finite element model. The result were as follows: 1. On bodily movement, the value of maximum force was 40.98Kg/cm2 at the (-X) direction and the stress area was the center of superiposterior nonaticular area of the condyle. 2. On ratational movement, the value of maximum force was 173.1Kg/cm2 at the (+Y) direction and the stress area was the anterior area of condyle neck. 3. From the general point of view there were more stress on rotational movement than on bodily movement. 4. The stress concentration area was the condyle head on bodily movement and the condyle neck on ratational movement. 5. From the result of this study. We found out that this results were a correspondence with clinical predictions in which a condyle head got the most stress concentration only when a condyle head in the posterior rotational position during orthognathic surgery. 6. The results of this study show that we should consider not to place the condyle head in the posterior position and posterior rotational position during orthognathic surgery.