Fibromyalgia in most cases is caused by TMJ:
There are multiple lines of evidence that fibromyalgia is caused by bite dysfunction in most cases. The mechanism is that bite misalignment causes the trigeminal nerve to become tonically elevated, thus causing its high density of C fibers to secrete substance P (see http://en.wikipedia.org/wiki/Substance_P) . This should have been recognized long ago when it was found that fibromyalgia patients have three to four times normal levels of sustance P in their spinal fluid. This cause has not been recognized since both dentistry and medicine are not aware that bite misalignment causes substance P to become elevated. Substance P is primarily associated with pain fibers (“c fibers”), of which the trigeminal nerve (jaw nerve) has over 100 times more density than any other nerve.
Substance P has two primary effects on the body: hypersensitizing all sensory neurons and mediating the inflammatory response. When sensory neurons become hypersensitized, one hurts when they shouldn’t to mild sensory stimulation. This also causes joints, organs, and tissues to become inflamed.
When one under goes TMJ splint therapy, the trigeminal nerve (jaw nerve) calms down. If done correctly and precisely, over time substance P levels will normalize. Substance P levels can be checked with a blood test (Quest Diagnostics Lab). On healthy patients I find substance P levels to be at 100 or less.
Jay Goldstein, MD, one of the early researchers in CFS/fibromyalgia, also found a strong connection between fibromyalgia and limbic brain dysfunction. He thought that treatment to the trigeminal system was the quickest, most responsive pathway for treating fibromyalgia. Please see article fibromyalgia: the trigeminal factor that I have written on fibromyalgia.