JAW MOVEMENT DURING MASTICATION OF FIBROUS AND NONFIBROUS COMPOSITE FOODS BY ADULT SUBJECTS

A cinematographic study was made of subjects during mastication of fibrous and nonfibrous foods. The motion of the jaw was analysed mathematically. Each cycle of the vertical movement of the jaw could be considered as a combination of a sinusoidal motion, chewing phase, and a linear one, jaw opening phase. The lateral movement was not so well defined. On average, females took longer to chew foods and had smaller jaw movements than males. Fibrous foods took longer to chew and the amplitudes were larger than nonfibrous foods. The maximum imum rate of jaw movement during chewing ranged from 15 mm s-1 to 30 mm s-1, with males chewing at faster rates than females.