无牙颌位的初步探讨

The Primary study of the edeutulous jaw position

本文通过对10例无牙颌总义齿修复后戴总义齿保持在正中硷位和不戴总义齿使上下颌残余齿槽嵴尽量闭合时颞颌关节的薛氏位X线片的对比分析,发现后者髁状突在关节凹内位置发生向后上旋转移位,下颌颏部发生了向上向前旋转移位。通过对其初步探讨,认为这一现象的发现有助于全面了解颞颌关节的生理功能和颞颌关节紊乱综合症的发生。对理解咬合运动的支点、髁道的可变性及指导总义齿的修复均有重要意义。

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.