This study was designed to evaluate masticatory performance in bruxist patients. The experimental group was composed of 16 dentate volunteers presenting with bruxism and treated by interocclusal appliances and a control group, consisting of 16 dentate volunteers with no symptoms of bruxism. To evaluate masticatory performance, the volunteers chewed .03 grams of peanuts contained in polyvinyl wrapper for four and twelve masticatory cycles. The number of chewed particles was counted using an optical scanning method by Image-Pro Plus 1.4 software (Media Cybernetics, Inc., Silverspring, MD). The score was expressed as the mean of the number of chewed particles for each wrapper. Masticatory performance evaluations were carried out in a single period for the control group and for the experimental group, before interocclusal appliance insertion, and after seven, 15, 30, and 60 days. Comparison between groups, as well as between before and after interocclusal appliance insertion, showed no significant differences (P>.05), irrespective of the number of masticatory cycles.234264268