Essay: Nerves and Jaw Reflexion
Stimulation of nerves in and around the teeth can also provoke inhibitory jaw reflexes. A study done in 2008 by Gardner et al to see which areas were stronger in conducting stimulation and stimulating a reflex. This was done on 9 human subjects and included electrode placement at the incisor tooth (pulpal stimulus) or across the alveolar spaces. The results showed that responses evoked from around the teeth were faster than those that were evoked as a result of pulp stimulation.
Jaw opening and the trigemino-hypogossal reflex can be illustrated by innocuous as well as noxious stimuli. In a study done in 1999 on anesthetized cats by Ono et al, electrical activity was recorded from the anterior digastric, genioglossus, and styloglossus muscles during swallowing which was done by dripping water on the tongue or repeated stimulation of the superior laryngeal nerve. Jaw opening was illicited by stimulation of the lingual nerve. It was found that low threshold stimulation was significantly suppressed during swallowing presumably by a central mechanism. This explains the phenomena that the jaws cannot be fully open while swallowing.