TMJ causes are various and such disorders develop for many reasons. Clenching or grinding your teeth tightens the jaw muscles and stresses the jaw joints. Injuries and joint disease can damage the joint cartilage or bone directly, or stretch or tear the muscle tendons. As a result, the cartilage disc, which is the “cushion” in the jaw joint, can slip out of position. TMJ disorders can result in a misaligned bite, joint and facial pain, limited jaw opening, or clicking or grating noise in the joints when you open your mouth.