TMJ dysfunction, often referred to as TMD, is a disharmony between the jaw joint and how the teeth fit together . Possible causes of this disharmony include tooth loss, accidents (like whiplash), mal-positioned and/or underdeveloped cranial or jawbones, and perhaps habits like clenching or teeth grinding. Many people go through life suffering from headaches and a variety of facial and neck pains without knowing the ultimate cause, which in many cases is a TMJ disorder.
When teeth are missing, or out of alignment, it causes the jaw to shift position, causing the muscles to have to work harder to chew, swallow, bite, etc, and eventually will cause muscle spasms, tension, and pain.
Muscle tension and misplaced TMJ could cause the TMJ disc to be pulled out of place which will result in pain, clicking and popping in the TMJ.