Jaw Reflexes Evoked by Mechanical Stimulation of Teeth in Humans

• Published in: Journal of neurophysiology Vol. 81; no. 5; pp. 2156 - 2163
• Main Authors: Yang, J, Turker, K. S
• Format: Journal Article
• Language: English
• Published: United States Am Phys Soc 01-05-1999
• Subjects: Adult; Bite Force; Electromyography; Female; Humans; Incisor - physiology; Jaw - physiology; Male; Masseter Muscle - physiology; Maxilla; Physical Stimulation - methods; Reflex - physiology; Time Factors
• ISSN: 0022-3077; 1522-1598
• DOI: 10.1152/jn.1999.81.5.2156

Department of Physiology, University of Adelaide, Adelaide, South
Australia 5005, Australia
Yang, J. and
K. S. Türker.
Jaw Reflexes Evoked by Mechanical Stimulation of Teeth in Humans. J. Neurophysiol. 81: 2156-2163, 1999. Jaw reflexes evoked by mechanical stimulation of teeth in humans.
The reflex response of jaw muscles to mechanical stimulation of an upper incisor tooth was investigated using the surface
electromyogram (SEMG) of the masseter muscle and the bite force. With a
slowly rising stimulus, the reflex response obtained on the masseter SEMG showed three different patterns of reflex responses; sole excitation, sole inhibition, and inhibition followed by excitation. Simultaneously recorded bite force, however, exhibited mainly one
reflex response pattern, a decrease followed by an increase in the net
closing force. A rapidly rising stimulus also induced several different
patterns of reflex responses in the masseter SEMG. When the
simultaneously recorded bite force was analyzed, however, there was
only one reflex response pattern, a decrease in the net closing force.
Therefore, the reflex change in the masseter muscle is not a good
representative of the net reflex response of all jaw muscles to
mechanical tooth stimulation. The net response is best expressed by the
averaged bite force. The averaged bite force records showed that when
the stimulus force was developing rapidly, the periodontal reflex could
reduce the bite force and hence protect the teeth and supporting
tissues from damaging forces. It also can increase the bite force; this might help keep food between the teeth if the change in force rate is
slow, especially when the initial bite force is low.