Often the first step in successful, long-term treatment of TMDs (temporomandibular disorders), occlusal splint therapy involves designing an acrylic splint from impressions and jaw relation records to enable the upper and lower teeth to meet in a way that is compatible with proper jaw function. The splint fits between the upper and lower teeth and is usually worn only at night to alleviate night-time clenching and grinding. Occlusal splint therapy is both therapeutic and diagnostic. It relaxes the muscles and enables the jaw to function properly, resulting in decreased discomfort. The splint also helps determine the precise bite relationship that will facilitate proper TMJ function, which in turn allows patients to create a healthy, natural bite by having their teeth reshaped or repositioned.