[The use of panoramic radiograph to observe abnormal movement of condyle]

The abnormal movement of mandible is one of the three chief symptoms of TMJDS, it is described usually by the degree and type of mouth opening. We use close and open mouth position panoramic radiographs of 144 cases with TMJDS to observe the relationship between the head of condyle and the articular eminence. It can show the different degrees of movement of condyle and the degree of movement of both sides to see they are in balance or not. We classified the movement of the condyle in to six types, and measure the degree of mouth opening on the same film. The rela-tionship between the result of them and the climnical symptoms are then analysed. We concluded that the supermovement of the condyle, which cause the acute and chronic trauma to the structures of TMJ and related muscles and ligaments, is one of the chief etiologic factors of TMJDS. The method and advantages of using panoramic radiography to observe movement of condyle are discussed.