In this blog article, Dr. Peter Dawson responds to a comment made on a previous article. The following was the comment:
It has been demonstrated repeatedly since 1997 that the relationship of bruxism to chronic craniofacial pain is non-linear. [1-4] In fact, 20% of the Raphael, et al, pain sample showed no bruxism. Lavigne lists among his finest work the discovery that sleep bruxism begins from an open mouth position with the action of the depressors.  This is not an “occlusal” problem beyond tooth wear, should the patient so decide.
That being said, the nature of the pain is such, particularly as it relates to headache, that keeping the posterior teeth apart with an appliance can prevent headache. As Mahan and Alling pointed out in their text , we have known that since 1960. 
Sessle, Dubner and colleagues have shown repeatedly that the pain of chronic M/TMD is not inflammatory.  Masticatory muscles are fatigue resistant over time, [9, 10] and the excess substance found is glutamate, not hydrogen ions from lactic acid in chronic craniofacial muscle pain. 
The blog post of April 25 is not supported by the current science.