A three-dimensional study of the retrusive movement of the mandible

Abstract

Retrusive movement from intercuspal position (ICP) to retruded contact position (RCP) has been investigated by many authors with various methods.However, 3 dimensional bodily movement of the mandible has not been yet enough investigated. The author wanted to clarify 3 dimensional movement pattern from ICP to RCP.The movements of 3 maxillary and 3 mandibular LED targets were measured and the retrusive movements of incisal point, 1st molars and condyles are calculated with Kyusyu University 3-D movement analyzing system. And also tooth contact was checked clinically.As the result, it was clarified that 3-D bodily retrusive movement pattern was more complex than had ever been thought. And the retrusive movement patterns of 10 cases were devided into 5 types. It is difficult to assume condyle movement from the observation of incisal retrusive movement. And tooth contact during retrusive movement act as an important role for movement pattern of the condyle.The discrepancy between ICP and RCP is thought to be one of etiologies of stomatognathic dysfunction. Therefore, when we examine patients of mandibular dysfunction, we had better keep in mind the complexity of the condyle movement.This article may give a basic suggestion as for mechanism of stomatognathic dysfunction.