Here's an interesting paper by a dentist describing anatomical mechanisms by which a number of Parkinson-like symptoms could in fact be caused by jaw problems.

"Parkinson’s Disease: are some cases in fact misdiagnosed Cranio-Mandibular Dysfunction?"
Dwight Jennings DDS, MICCMO
Alameda, California
http://web.me.com/thriiive/Summit_9/...ONTMJpub-1.pdf

(Neither a publication, nor a date are given. Judging by the references I'd estimate that it was written in 2008.)

For instance, Jennnings writes:

"Tremor:
Multiple case histories have shown an unclear connection between bite and tremors. The suspected mechanism is thought to be trigeminal input into the reticular formation."

"Masked Face:
The trigeminal nerve is known to have the ability to modulate muscles of facial expression. ... This I have seen demonstrated numerous times clinically when chronic Bell’s palsy symptoms resolve with jaw orthopedic therapy."

John