Chewing Patterns in Subjects with Normal Occlusion and With Malocclusions

This report describes the chewing patterns of individuals with normal occlusion and several types of malocclusion. Frontal movement patterns of the lower mid-incisor point were recorded during chewing of test foods in groups of subjects with Angle Class I normal occlusion, Class II malocclusion, as well as deep-bite and cross-bite malocclusions. Mandibular prognathic and retrognathic patients corrected to Angle Class I occlusions were also examined before and after orthognathic surgery. Chewing patterns were classified by using a catalogue of eight basic movement types. In none of the groups examined could chewing behavior be characterized by only one specific type of movement, but rather by different frequency distributions of pattern types. The Angle Class I, Class II, deep-bite, and presurgical retrognathism groups were characterized by chewing patterns with normal sequencing and grinding features and, to a minor extent, by self-crossing movements having no unique pattern of sequencing. Reversed sequencing did not occur in these four groups. In presurgical prognathic patients, drop-shaped patterns with steep closing movements predominated. Cross-bite malocclusion was characterized by drop-shaped and reversed sequencing patterns. The pattern distribution in prognathic patients did not change after surgery. In retrognathic patients the therapeutically altered occlusion caused a decrease in the frequency of grinding movements and an increase in the frequency of drop-shaped patterns.