A study of the effects of chewing patterns on occlusal wear.

The chewing cycle is a functional movement, closely related to occlusion, the neuromuscular system and the central nervous system. Although actual chewing paths are complicated and vary from individual to individual, there are two typical patterns. One is more vertical in nature and is similar to a chopping movement. The other is a more lateral type that is similar to a grinding movement. The purpose of this study was to evaluate the effects of chewing patterns on occlusal wear. Fifteen subjects exhibiting a chopping-chewing pattern and 15 subjects exhibiting a grinding-chewing pattern were selected using a jaw tracking device. The occlusal wear values, obtained by both ordinal and Woda's arbitrary scales, and frequencies of non-working facets were calculated for each group. The occlusal wear values in all teeth and in each segment, obtained by the use of the ordinal scale did not vary significantly between the chopping and the grinding type group. However, the occlusal wear values of the grinding type group in all teeth and in posterior teeth segments, obtained by the use of Woda's arbitrary scale, were significantly greater than those of the chopping type group. Frequencies of non-working facets in posterior teeth showed no significant differences between the groups.