The use of interocclusal orthopedic appliances is the most common method for managing nocturnal bruxism and associated craniomandibular symptoms. Yet there is no design for optimal clinical results. Posterior disocclusion th rough canine or anterior guidance is believed to be a key feature. The purpose of this study was to compare a canine versus molar guidance appliance in eight chronic bruxist patients. The appliances were used to 10 to 14 nights. The two appliances provided nearly equivalent effects on nocturnal bruxism in seven of eig ht subjects. Clinical examination and subjective pain ratings did not differ with the two guidance patterns. These r esults question the common assumption that canine guidance is a critical design feature for the management of nocturnal bruxism and associated craniomandibular symptom