Changes in the three-dimensional appearance of masticatory forces as mastication progresses

Abstract

I investigated changes in masticatory force vectors in the mandibular first molar as mastication progressed. Peanuts and raisins were used as the test materials in four subjects with normal stomatognathic function. As mastication progressed, the duration, peak and impulse of the vertical and resultant forces decreased, while the lateral forces, and in particular their peak values, showed no significant change. Also, the impulse ratio of lateral to resultant force increased. The angle of the resultant force with vertical increased over time when this force peaked. Directional changes in the vector during a single masticatory stroke decreased as mastication progressed, and the vector of resultant forces was vertical during the closing phase.