The Primary study of the edeutulous jaw position

The radilgrapby of temporomandibular joint （TMJ） of Schuller's position was made for 10 patient in two positions, one when patients wore the complete denture and kept in the intercuspal position, another when they did not wear the complete denture bur made the upper and lower residual ridges contact as closely as possible. This is refered to as edentulous jaw position. The comparative study was made between two groups.
The result showed that after all the teeth lost, the upper and lower residual ridges contacted as closely as possible, the condyle became able to move backward and upward in glenoid fossa, with mental part of mandible moved upward and forward. The vertical dimension decreased. This movement stopped when the upper residual ridge contacted with lower one of ramus of mandible. Basing upon this, a concept of edentulous jaw position is put forward for the first time. It indicates that condyle is not a fixed fulcrum of masticatory movement, while the tooth can be the fulcrum of masticatory movement. According to this study, it is possible that a movable functional occlusal position with a movable condylar pathway exists. But if it is beyond the limit of its physiological adaptation, TMJDS may be the result.