Normal masticatory performance in young adults and children.

Previous studies have paid little attention to either the development or sexual dimorphism of masticatory performance. The aim of this study was to measure and compare the masticatory performance of adults and children. Forty-seven healthy and normal individuals (15 adult men, 15 adult women, 15 young girls and 2 young boys) were selected, based on their occlusion, temporomandibular joint function, skeletal classification, and the state of their dentition. Masticatory performance was evaluated by the individual's ability to break down a standardized bolus. Cuttersil impression material was chewed for 20 strokes, spat out, dried, and passed through a series of seven sieves. The Rosin-Rammler equation was used to calculate the median particle size and broadness of particle distribution. Measurements of dentitional surface area, contact area, bite force, mandibular morphology, and body size were also taken as covariates. The results showed significant differences in masticatory performance among the three larger groups; men performed best, followed by women then girls. Multiple regression analyses showed that body size was the most important variable associated with differences in masticatory performance. Adjusting for weight eliminated the group differences. Body size, together with the occlusal contact area of the posterior teeth and the bite force, explained 60-72 percent of the variation in performance. Contact area, posterior ramus height, and bite force explained differences between men and women, but differences between adults and children remained.