Spaciostructural analyses of mandibular and perioral soft tissue movementsduring mastication

We considered that elucidation of the movements of perioral soft tissues du ring mastication would be useful in evaluating masticatory movements. Howev er, evaluation of movements specific to soft tissues is difficult because m ovements of the surface of the lower face during mastication include moveme nts of the muscles of facial expression and mandibular movements. The aims of this study were to elucidate the influence of mandibular movements on pe rioral soft tissue movements during mastication using principal component a nalysis (PCA) and to abstract the component of movement specific to soft ti ssues in order to evaluate masticatory movements from the movements of peri oral soft tissues. The subjects were 10 healthy persons with complete natur al dentition. The experimental food used in this study was sufficiently sof tened chewing gum. The results of this study showed that the movements of m andibular and perioral soft tissue were closely related in the first and th ird PCs; in other words, the second PC was the component of movement specif ic to soft tissues. Thus, elucidation of the second PC is useful for evalua tion of masticatory movements from movements of perioral soft tissues.