Effects of intense chewing exercises on the masticatory sensory-motor system.
Nociceptive substances, injected into the masseter muscle, induce pain and facilitate the jaw-stretch reflex. It is hypothesized that intense chewing would provoke similar effects. Fourteen men performed 20 bouts of 5-minute chewing. After each bout, 20 min and 24 hrs after the exercise, muscle fatigue and pain scores and the normalized reflex amplitude from the left masseter muscle were recorded. Before, 20 min, and 24 hrs after the exercise, signs of temporomandibular disorders and pressure-pain thresholds of the masticatory muscles were also recorded. Fatigue and pain scores had increased during the exercise (P < 0.001), but the reflex amplitude did not (P = 0.123). Twenty minutes after the exercises, 12 participants showed signs of myofascial pain or arthralgia. Pressure-pain thresholds were decreased after 20 min (P = 0.009) and 24 hrs (P = 0.049). Intense chewing can induce fatigue, pain, and decreased pressure-pain thresholds in the masticatory muscles, without concomitant changes in the jaw-stretch reflex amplitude.
Koutris
M
M
Department of Oral Function, Section of Oral Kinesiology, Academic Centre for Dentistry Amsterdam (ACTA), Louwesweg 1, 1066 EA Amsterdam, The Netherlands.
Lobbezoo
F
F
Naeije
M
M
Wang
K
K
Svensson
P
P
Arendt-Nielsen
L
L
Farina
D
D
D000328:Adult; D015444:Exercise / Q000502:physiology; D005157:Facial Pain / Q000209:etiology; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology*; D008409:Mastication; D018763:Muscle Fatigue / Q000502:physiology*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology; D012026:Reflex, Stretch; D055815:Young Adult