Temporomandibular joint (TMJ) disorders cause pain and poor function in the jaw joint and the muscles responsible for jaw movement. TMJ can be just a nuisance, or even a life-altering problem. When it’s less severe, crunching down on a hard bit of food can be painful through the jaw joint – unpleasant, but not serious. With severe cases, however, simple tasks like eating or talking, can be difficult, or debilitating. Even sleeping with this disorder can be problematic since the disc within the jaw joint may slip out of position during sleep, causing the mouth to not open properly upon wakening.