I also grind my teeth but it is in my sleep so I have a bite guard to protect my teeth. It's a reaction to stress I have been told and because I do this it damages, as you said, my teeth. If you were to do this while awake you would also be able to feel the tention it creates at the temples of your head. This grinding and clenching can also be a cause of headaches especially if you wake in the morning with one.
pherazone