A Night Guard (also called bruxism appliance) is a transparent, thin device you wear over the biting surface of your teeth when sleeping. Most of Bruxism can easily be treated by wearing a Night Guard while you sleep. A Night Guard is also available through your dentist. Guards tend to be of a higher quality and superior fit, as they are made in a dental laboratory from an impression of your mouth carefully taken by a dentist. This is generally a more expensive device than one purchased over-the-counter, but can be more comfortable to wear. Whatever where a Night Guard is purchased, its main function is to prevent the surfaces of your teeth from grinding together, causing you to chip and crack your teeth and strain your jaw muscles.