Grind Your Teeth? Your Night Guard May Not Be the Right Fix – The New York Times:

simple awareness of the position of your mouth, tongue and teeth throughout the day may go a long way toward preventing tooth-grinding. “Nobody knows where their tongue is when they are at rest,” said Cheryl Cocca, a physical therapist at Good Shepherd Penn Partners in Lansdale, Pa., who treats patients with bruxism. She recommends continually checking to make sure you are breathing through your nose with your mouth closed, your tongue resting on the roof of your mouth, and your teeth apart.