순간 회전 중심 결정과 하악골 운동에 관한 연구

A Study on the Determination of Instantaneous Centre of Rotation and the Mandibular Movement

Recently the instantaneous centre concept has been used to understand the biomechanics by which a tissue derangement causes a mechanical derangement in temporomandibular joint. In this study, four male subjects without temporomandibular joint disorder and malocclusion were selected for the determination of the instantaneous centre of rotation (I.C.R) in the mandibular movement. The habitual opening and closing paths were recorded on the sagittal plate by two spring pencils attached on the lower anterior teeth which was designed for this study, and the I.C.R. was calculated by the computer program of Rouleaux's method. Also the computer graphic opening and closing movements of mandible were obtained according to the determined I.C.R. The results obtained from this study were as follows. 1. The instantaneous centres of rotation were not positioned within the condyle in the mandibular opening and closing movement. 2. There was some similarity between the anatomical curvature of the articular emience and the movement pattern of condyle. 3. The opening path and the closing path of the most superior pl)int of the condyle stowed a slight difference. 4. At the early stage of the habitual opening movement, the condyle was moved downward. 5. The opening and closing mandibular movements were simulated by the instantaneous centre of rotation which was determined by the computer program of Rouleaux's method.