This is a common misconception; mouthguards are not there to protect your teeth. They are there to keep you from getting a concussion. Often times when you bash or knock your head your jaw will snap shut, quite forcefully at that. The shockwave or whathaveyou is strong enough to hurt the jelly inside your nut. It has been my personal experience that the mouthguard will actually do more damage to your teeth than not using them in a jaw-snap-shut situation, but i'd rather jack my teeth than my brain.

In conclusion, yes, you *should* wear one. No, i must admit, i don't.