TMJ disorders develop for many reasons. You might clench or grind your teeth, tightening your jaw muscles and stressing your TM joint. You may have a damaged jaw joint due to injury or disease. Injuries and arthritis can damage the joint directly or stretch or tear the muscle ligaments. As a result, the disk, which is made of cartilage and functions as the cushion of the jaw joint, can slip out of position. Whatever the cause, the results may include a misaligned bite, pain, clicking, or grating noise when you open your mouth or trouble opening your mouth wide.