A mouthguard is a protective device for the mouth that covers the teeth and gums to prevent and reduce injury to the teeth, arches, lips and gums. A mouthguard is most often used to prevent injury in contact sports, as a treatment for bruxism or TMD, or as part of certain dental procedures, such as tooth bleaching. Depending on application, it may also be called a mouth protector, mouth piece, gumshield, gumguard, nightguard, occlusal splint, bite splint, or bite plane.

The exact origins of the mouthguard are unclear. Most evidence indicates that the concept of a mouthguard was initiated in the sport of boxing. Originally, boxers fashioned rudimentary mouthguards out of cotton, tape, sponge, or small pieces of wood. Boxers clenched the material between their teeth. These boxers had a hard time focusing on the fight and clenching their teeth at the same time. Since these devices proved impractical, Woolf Krause, a British dentist, began to fashion mouthpieces for boxers in 1892. Krause placed strips of a natural rubber resin, gutta-percha, over the maxillary incisors of boxers before they entered the ring. Phillip Krause, Woolf Krause’s son, is often credited with the first reusable mouthpiece. Phillip Krause’s invention was highlighted in a 1921 championship fight between Jack Britton and Ted “Kid” Lewis. Lewis was a school friend of Krauses’ and the first professional to utilize the new technology, then called a ‘gum shield.’ During the fight, Britton’s manager successfully argued that the mouthpiece was an illegal advantage. Philip Krause was an amateur boxer himself and undoubtedly used his own device before 1921.