ive had some of the worst clenching u can imagine...and its not fun the next day if u clench enough. ur jaw is sore,and my mine clicks once in a while from what i think is a result of clenching while rolling for so long (when i clench i tend to not notice)
Magnesium can help. A couple of mouthfulls of milk of magnesia before your roll usually cuts down on the jaw clenching a good bit, don't take too much of it though it's a strong laxative at higher doses.
I always clench when I roll. I tend to get something to chew on (pacifier, gum, whatever) but you just gotta be aware of it so your jaw isn't killing you the next day. But it's never affected my roll.
yeah, of course it wouldnt affect your roll, but it will make ur jaw sore the next day. or even fracture teeth like superpimp lol that sux dude. the only method that has worked for me is chewing gum, but when i spit the gum out i go right back to clenching my jaw...
for some reason I rarely clench my jaw. My friends have some serious jaw clenching problems but I can usually just let it hang loose =P