A model for optimum functional human jaw movements based on values associated with preferred chewing patterns.

Jaw movements during voluntary chewing were recorded from 15 normal subjects with a sirognathograph. A computer program was used to provide a graphic display of the closing strokes in the frontal plane. A record was made of the side from which the jaw approached a central occlusal position. An average of 90 closing strokes was recorded for each subject. In 10 of the subjects, statistical differences were found between the use of the right- and left-hand sides. In these subjects this preference was confirmed by analysis of results from a second set of observations. A model was derived, using multiple regression analysis, which identified a relationship between four jaw-movement variables and an index of preference. A broad chewing pathway, with a bilateral distribution, together with a wide sagittal pathway were characteristics associated with preference. An indication of optimal jaw-movement patterns may be derived from identifying movement variables associated with preferred chewing.