A mouthguard is a device that fits into the mouth over one or both arches of teeth. They are typically made of vacuum-formed plastic. Mouthguards may be used to protect against injury during sports, or they may serve a medical purpose such as splints used to treat temporomandibular joint dysfunction and bruxism. Also, a thin, acrylic mouthguard appliance is often used during tooth bleaching.

The mouthguard was co-invented by Dr. A. W. S. Wood (a paediatric dentist) as a way to prevent injuries to children's teeth in hockey games. ^*

Dental equipment | Protective gear