A mouthpiece for braces is virtually the same as any regular mouthpiece with the exception that it provides a bit more room to accommodate the brackets of the braces. Mouthpieces, also known as mouth guards, are sometimes used in dental procedures, such as bleaching your teeth, but they are more commonly seen on athletes in the field.
There are many sports, such as football, hockey or martial arts, which involve heavy physical contact and can result in breaking or otherwise damaging your teeth. Gums are also in need of protection, as they can easily be cut or inflamed. Concussions can also be avoided from unbearably heavy impacts of the jaw that can occur in some sports. For these reasons, athletes will wear mouth guards for protection.