ATHLETIC MOUTHGUARDS AND NIGHTGUARDS Custom designed mouthguards and nightguards are made of flexible plastic and molded to fit the shape of your teeth. Mouthguards are recommended to protect the jaw and teeth during physical activity and sports such as boxing, football, basketball, or other similar activities. In addition, these guards protect the soft tissues of your tongue, lips, and cheek lining. Nightguards are recommended for patients who clench or grind their teeth at night as a way to protect their teeth and bite. If the dentist decides a guard is right for your child, he will take an impression of their teeth. This impression will then be sent to a lab to make a custom fit guard. In many cases, you can choose from a variety of colors and styles for your guard.