Analysis of jaw opening reflexes

Electromyograms were compared with kinematograms recorded for 35 male dental students, average age 25 years, with full occlusions and without temporomandibular joint dysfunction. The records were obtained during the open-close-clench cycle rhythmically performed as the patient occluded on the molar teeth. The mechanical tracings disclosed seven subjects with centric slide and the duration of the cycle was significantly longer than normal. The kinematographic latency of the jaw opening reflex was found to be about equal to the sum of the electromyographic latency and inhibition.