You don't have to keep you're teeth clenched to keep it in, though I think it may naturally happen because it's in your mouth. The principle behind the bite plate is to protect your teeth, so if you grind, it doesn't wear down your enamel and cause recession in gums (which is what grinding can do). It's a good question though about how it would make you stop grinding, because for me it hasn't. I've ground through 3 bite plates over a period of 10 years. I also don't know how it protects your jaw either, aside from possibly cushioning the impact from grinding.