Treatment of occlusal-related disorders is often a challenge for both the dentist and the patient. These disorders are often difficult to diagnose, as the presenting symptoms can be variable. Occlusal splint design and function can be considered an example of the art and science of dentistry. Once the cause of occlusal-related disorders is identified, this reversible, noninvasive therapy provides both diagnostic information and relief without the problems that often accompany other approaches to care, ie, surgery and extended drug therapy. The basic principles of occlusal splint therapy for treating temporomandibular disorder (TMD), bruxism, and some forms of headache.