INCLINATION OF THE OCCLUSAL PLANE AND OCCLUSAL GUIDANCE AS CONTRIBUTING FACTORS IN MASTICATION

Objectives: The purpose of the present study was to compare the inclin ation of the occlusal plane with occlusal guidance as a contributing f actor to masticatory movement. Methods: Masticatory movements of 41 yo ung adults were measured using a 3-D mandibular movement analysing sys tem. The inclination of the occlusal plane was measured in the sagitta l plane using a 3-D digitizer. The contribution of the occlusal guidan ce and the inclination of the occlusal plane to the direction of the m asticatory path of closure was evaluated at various closing levels. Re sults: The masticatory path of closure outside the intercuspal range w as influenced mainly by the inclination of the occlusal plane, and the masticatory path of closure near the intercuspal range was only influ enced by occlusal guidance. The so-called gliding type masticatory pat tern was observed predominantly in subjects with a posteriorly incline d occlusal plane. In contrast, a chopping type masticatory pattern was observed predominantly in subjects with an anteriorly inclined occlus al plane. Conclusions: The contribution of the inclination of the occl usal plane to masticatory movement was greater than that of occlusal g uidance throughout the closing phase except near the intercuspal range . (C) 1998 Elsevier Science Ltd. All rights reserved.