Teeth Grinding?!

Teeth Grinding?

I grind my teeth or clench my jaw, unconsciously when im tired or stressed, and often when im driving my car! Sounds weird I know, that doesnt so much bother me, but I grind my teeth quite noisily when I sleep and I really wish i didnt. It wakes up my partner, and I end up with a sore jaw. Apart from consciously trying not to do it, does anyone have any advice or insight into what causes it, and how to stop?

My sister does it in her sleep, too, and she uses a grind guard at night. I do it when I'm stressed, too, and usually catch myself and try to relax, or do something else to release the pressure, like squeezing a stress ball, or clenching my hands instead.

Here's some info for you:
http://www.mayoclinic.com/health/bruxism...
http://en.wikipedia.org/wiki/bruxism...
http://www.stanford.edu/~dement/bruxism....