Effects of a bite-raising splint on the duration of the chewing cycle and the EMG activities of masticatory muscles during chewing in freely moving rabbits

Metal bite-raising splints of 0.5 mm thickness were attached to the upper molar teeth on both sides of the jaw in rabbits. The effects of these splints on masticatory behaviour during the chewing of soft food (bread) by freely moving rabbits were investigated. We recorded electromyograms (EMGs) of the masseter and digastric muscles. The animals exhibited prolongation of the chewing cycle, decreased EMG activity of the masseter muscle and increased EMG activity of the digastric muscle during chewing after introduction of the bite-raising splints. The effects of the splints on the activities of masticatory muscles were abolished by bilateral sectioning of the maxillary and inferior, alveolar nerves. It seems likely that afferents from oral sensory receptors were responsible for the changes in masticatory behaviour after the introduction of the occlusal splint.