Bruxism, or the grinding and clenching of teeth, occurs in approximately 15 percent of children and in as many as 96 percent of adults. The etiology of bruxism is unclear, but the condition has been associated with stress, occlusal disorders, allergies and sleep positioning. Because of its nonspecific pathology, bruxism may be difficult to diagnose. In addition to complaints from sleep partners, signs of teeth grinding include masticatory pain or fatigue, headaches, tooth sensitivity and attrition, oral infection and temporomandibular joint disorders. Signs of bruxism include tooth wear and mobility, as well as tender or hypertrophied masticatory muscles and joints. Children with bruxism are usually managed with observation and reassurance. Adults may be managed with stress reduction therapy, alteration of sleep positioning, drug therapy, biofeedback training, physical therapy and dental evaluation. If significant tooth attrition, mobility or fracture occurs, dental referral is mandatory.