Nonfunctional and functional occlusal contacts: a review of the literature

A review of the literature on occlusal contacts emphasizes the following points. 1. Contacts in centric occlusion do not correspond to any ideal occlusal diagram. 2. Canine protection and group function appear to correspond to two successive states of the evolving dentition under the effect of abrasion. In most lateral occlusions, two maxillary teeth, of which one is the canine, are involved. 3. During mastication, tooth contacts exist. They occur most often during a sliding movement in which the direction and the origin are variable. This justifies the concept of an occlusal field of mastication. 4. During unilateral mastication, the chewing of the food is performed by working as well as nonworking contact. This imposes the distinction between the chewing and nonchewing sides (functional) and the working and nonworking sides (kinematic). 5. Centric occlusion is the occlusion most often used during mastication. It is also the occlusion for which the masticatory forces are the greatest. 6. The bibliographic data concerning occlusal contracts during swallowing are largely contradictory. It nevertheless seems that the occlusal contacts obey laws nearly the same as those governing the occlusal contact during mastication (sliding on an occlusal field of deglutition, and the importance of centric occlusion).