|The relationship of Myofascial Pain, Tension-type Headache,
and Temporalis Contraction Intensity
As the intensity of temporalis contraction increases, without any activity from the lateral pterygoids, the severity of temporal pain (headache) increases in the absence of any typical TMD symptoms (graph). Myofascial pain and dysfunction of the temporalis is described by Travell as "Temporal Headache", and can be caused and/or perpetuated by chronic nocturnal intense temporalis contraction (1) (L). Tension-type headache patients without signs or symptoms of TMD (3) clench their jaws during sleep, on average, 14 times more intensely than asymptomatic controls (2) (M). Temporalis clenching without lateral pterygoid involvement does not cause strain on the TMJ (slide 2).
Chronic temporalis clenching without lateral pterygoid involvement can be considered a type of bruxism, that is, "Primary Clenching".
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