Mouth guards are coverings worn over teeth, and often used to protect teeth from injury from teeth grinding and during sports.

Generally, mouth guards cover your upper teeth only, but in some instances (such as if you wear braces or another fixed dental appliance on your lower jaw), your dentist will make a mouth guard for the lower teeth as well. Your dentist can suggest the best mouth guard for you. An effective mouth guard should be comfortable, resist tears, be durable and easy to clean, and should not restrict your breathing or speech.
If you grind your teeth at night, a special mouth guard-type of dental appliance — called a nocturnal bite plate or bite splint — may be created to prevent tooth damage.
Who Needs a Mouth Guard?
Mouth guards should be used by anyone — children and adults — who play contact sports such as football, boxing, soccer, ice hockey, basketball, lacrosse, and field hockey. However, even those participating in noncontact sports (for example, gymnastics) and any recreational activity (for example, skateboarding, mountain biking) that might pose a risk of injury to the mouth would benefit from wearing a protective mouth guard.
Adults and children who grind their teeth at night should have a nocturnal bite plate or bite splint made to prevent tooth damage.
Why Use a Mouth Guard When Playing Sports?
Because accidents can happen during any physical activity, the advantage of using a mouth guard during sports is that it can help limit the risk of mouth-related injuries to your lips, tongue, and soft tissues of your mouth. Mouth guards also help you avoid chipped or broken teeth, nerve damage to a tooth, or even tooth loss.
See also: Night Guard and Sports Mouth Guards