context: Mouth guards are coverings worn over teeth, and often used to protect teeth from injury from teeth grinding and during sports. There are three types of mouth guards: Stock mouth protectors are preformed and come ready to wear. They are inexpensive and can be bought at most sporting good stores and department stores. However, little can be done to adjust their fit, they are bulky, make breathing and talking difficult, and they provide little or no protection. Dentists do not recommend their use. Boil and bite mouth protectors also can be bought at many sporting goods stores and may offer a better fit than stock mouth protectors. The "boil and bite" mouth guard is made from thermoplastic material. It is placed in hot water to soften, then placed in the mouth and shaped around the teeth using finger and tongue pressure. Custom-fitted mouth protectors are individually designed and made in a dental office or a professional laboratory based on your dentist's instructions. First, your dentist will make an impression of your teeth and a mouth guard is then molded over the model using a special material. Due to the use of the special material and because of the extra time and work involved, this custom-made mouth guard is more expensive than the other types, but it provides the most comfort and protection. Generally, mouth guards cover your upper teeth only, but in some instances (such as if you wear braces or another fixed dental appliance on your lower jaw), your dentist will make a mouth guard for the lower teeth as well. Your dentist can suggest the best mouth guard for you. An effective mouth guard should be comfortable, resist tears, be durable and easy to clean, and should not restrict your breathing or speech. If you grind your teeth at night, a special mouth guard-type of dental appliance -- called a nocturnal bite plate or bite splint -- may be created to prevent tooth damage. Mouth guards should be used by anyone -- children and adults -- who play contact sports such as football, boxing, soccer, ice hockey, basketball, lacrosse, and field hockey. However, even those participating in noncontact sports (for example, gymnastics) and any recreational activity (for example, skateboarding, mountain biking) that might pose a risk of injury to the mouth would benefit from wearing a protective mouth guard. Adults and children who grind their teeth at night should have a nocturnal bite plate or bite splint made to prevent tooth damage. Because accidents can happen during any physical activity, the advantage of using a mouth guard during sports is that it can help limit the risk of mouth-related injuries to your lips, tongue, and soft tissues of your mouth. Mouth guards also help you avoid chipped or broken teeth, nerve damage to a tooth, or even tooth loss. Yes. Since an injury to the face could damage braces or other fixed appliances, a properly fitted mouth guard may be particularly important for people who wear braces or have fixed bridge work. Your dentist or orthodontist can determine the mouth guard that will provide the best protection for your unique mouth work. An important reminder: do not wear any orthodontic retainers or other removable appliance during any contact sports or during any recreational activities that put your mouth at risk for injury. One exception is invisalign trays, which can often be worn during sports sometimes along with a mouth guard. If you are using visalign trays and playing sports, check with your dentist about wether or not and how you should wear them. To care for your mouth guard: Rinse your mouth guard with cold water or with a mouth rinse before and after each use or clean it with a mild soap and a toothbrush. Clean the mouth guard in cool, soapy water and rinse it thoroughly. Place the mouth guard in a firm, perforated container to store or transport it. This permits air circulation and helps to prevent damage. If the mouth guard is acrylic, keep it in fresh clean water. Protect the mouth guard from high temperatures -- such as hot water, hot surfaces, or direct sunlight -- to minimize distorting its shape. Occasionally check the mouth guard for general wear. If you find holes or tears in it or if it becomes loose or causes discomfort, replace it. Bring the mouth guard to each regularly scheduled dental visit to have your dentist exam it.