Influence of the Sitting Posture Including the Position of the Head and Neck on Chewing Efficiency of Healthy Adults

Abstract

This study was performed to investigate the influence of changes in posture during feeding on masticatory efficiency. [Subjects] Subjects were 23 healthy young adults. [Methods] The subjects were asked to adopt four postures in a random order. The activity of the masseter muscle was recorded by electromyography from the beginning of chewing to the end. The number of chewing strokes, total chewing time, chewing rhythm and coefficient of variation of chewing rhythm were compared among the postures. [Results] The number of chewing strokes was significantly greater in R30-HN30 than in R90-HN0. The total chewing time was significantly longer in R30-HN0 and R30-HN30 than in R90-HN0. Burst duration was longest in R30-HN0. Cycle time was significantly longer in R30-HN0 than in R90-HN0. The coefficient of variation of burst duration was significantly greater in R30-HN0 than in R90-HN0. [Conclusion] Masticatory efficiency is the best in R90-HN0.