A nightguard is a dental appliance that is worn during sleep. There are many forms of nightguards, with the most common types being very similar in appearance to a mouthpiece worn by athletes. A nightguard is fabricated by a dentist and its purpose is either to prevent teeth, crowns, or veneers from chipping during sleep, or to help prevent clenching and grinding during sleep. A properly fitted nightguard fits tightly and comfortably, and must be made to evenly occlude (or touch) the opposing teeth. An improperly made nightguard can cause worsening joint issues and discomfort. Some patients have trouble adjusting to wearing a nightguard, but most people find the relief and protection they provide to be indispensable.