"Bruxism" means grinding and/or clenching of teeth. It is a nonfunctional habit that can occur while awake or asleep. Grinding your teeth while asleep is more of a problem since most people will grind their teeth much harder than they ever would while awake. Such "Nocturnal Bruxism" is a very common sleep behavior that a many people will experience at some time in their lives.
A nightguard is the best treatment for bruxism. A night guard is a thin piece of hard plastic made from impressions of your teeth placed on the upper or lower teeth. The nightguard is hard enough to be durable, but since it is softer than teeth it will protect them from wear.
Bruxism is a problem if evidence of worn enamel exists and/or if painful jaw symptoms develop. One can grind their teeth so hard that significant amounts of tooth structure can be lost over time. This insidious destruction of enamel can be quite extensive, causing more loss of tooth structure than even severe tooth decay. Typically this happens with no awareness by the patient since there is no pain or visible cavities in the teeth. One major goal of a nightguard is to stop this destruction of tooth structure as soon as possible. Otherwise, the teeth effected would need extensive, costly dental work to be restored.
Often nighttime bruxism is accompanied by pain in the jaw joint and/or muscles. Even if no pain is present, wearing a nightguard may aid in preventing the development of this painful problem, and protect the jaw joints from excessive pressure that may lead to damage in them.
You need to wear the night guard each night for it to work properly.