[Effects of experimental premature contacts on the mandibular rest position]

The effects of experimental premature contacts (PC) on the mandibular rest position (RP) were investigated using 5 subjects. Metal castings were fabricated for the unilateral maxillary teeth to simulate various premature contacts. Subjects were asked to sit with their mandible relaxed after 50 tapping efforts at different force levels, and positions of their mandible were measured for 180 seconds. Furthermore, subjects were divided into two two groups depending on their chewing patterns; one was grinding type and the other was chopping type group. The results were as follows: 1. The area of RP after the insertion of PC differed from that of RP without PC. 2. There was a positive correlation between the width of distribution of RP without PC and the amount of the RP change after the insertion of PC. 3. The RP shift pattern of grinding type subjects showed the tendency to be influenced strongly by the tapping forces, while that of chopping type subjects was less influenced. 4. The results of this study suggest that the nature of reception of the stimulus by the premature contact has some relationship to one's own chewing pattern.