What protective item is placed in a boxer's mouth during a bout?

A mouthguard is placed in a boxer’s mouth to protect the teeth and gums during a bout.

The flexible device cushions impacts to the mouth and helps prevent teeth, lips, gums and the arches of the mouth from being damaged. It also separates the upper and lower teeth, which can reduce some jaw-related injuries. A mouthguard is sometimes called a gum shield, mouthpiece or mouth protector.

The concept is strongly associated with boxing. Before modern equipment, fighters reportedly used improvised materials such as cotton, tape, sponge or small pieces of wood. British dentist Woolf Krause is credited with fashioning boxing mouthpieces from gutta-percha in 1892, although other inventors later made competing claims.

Today, athletes commonly use stock guards, “boil-and-bite” guards molded with heat, or custom-made guards fitted by a dentist. A mouthguard is not the same as headgear, which protects the head, or a groin guard, which protects the lower abdomen. It also does not make a boxer immune to concussion or facial injury.