A mouth guard is a soft plastic device that is used in sports to prevent oral injuries to the teeth, mouth, cheeks, tongue and jaw. The American Dental Association projects that one third of all dental injuries are sports related. These injuries include chipped or broken teeth, fractured crowns, lip and cheek bruises, root damage to the teeth, fractured jaws and concussions. Any athlete may be at risk for oral injury and any injury can be prevented with the use of a mouth guard. The ADA recommends that people of all ages use a properly fitted moth guard in any sporting or recreational activity that may pose a risk of injury.