Accidents can happen during any physical activity. A mouth protector can help protect the soft tissues of your tongue, lips and cheek lining. Over-the-counter stock mouth protectors are inexpensive, pre-formed and ready-to-wear. Boil and bite mouth protectors offer a better fit than stock mouth protectors. Softened in water, they are more adaptable to the shape of your mouth. Custom-fitted mouth protectors are made by your dentist for you personally. They are more expensive, but a properly fitted mouth protector will stay in place while you are wearing it, making it easy for you to talk and breathe.