You absolutely need to be fit for a custom bite guard if you participate in sports or activities that put your oral health at risk. These guidelines also apply to children, who often play sports like football or participate in activities like martial arts, which can cause tooth-related injuries. You may also need a bite guard if your dentist diagnosis you with bruxism, or tooth-grinding. Over time, grinding or clenching the teeth can lead to wear and irreversible damage. Sleeping with a bite guard can protect the teeth from these unwanted side effects.