I think I have bruxism. There was an article in the Houston Chronicle today that described the condition of "involuntary teeth gnashing". I usually wake up with my jaws tightly clenched, which sometimes makes my jaw ache. I don't think I do much gnashing, just clenching.
My dentist asked about it at my last appointment, so there must be some evidence on my teeth as well. Actually, he asked my wife (instead of asking me) if she noticed if I ground my teeth. She didn't, but that means this has been going on for a while now. I have my next dentist appointment next week, so I'll ask about it then. I may have to start wearing a mouth guard. Ick.