Pain at the TM joints is usually due to an inflammation of the ligaments that hold the two bones – temporal and mandibular bones – together and form a capsule around the joint. This Capsulitis is in turn due to strain in the joint from clenching or grinding very hard in deep sleep. The underlying cause of this is the disharmony of the bite – a malocclusion.
The other causes of pain in TM joints are due to internal derangement – a torn ligament that acts as the tether for the articular disc between the two bones. The disc is meant to act as a bearing between the articular surfaces of the bones when they function. When the disc is dislocated, at some point during opening of the jaw the disc will pop in to place causing the clicking noise.
When this dislocation is uncorrected, it could lead to destruction of the joint surfaces and result in arthritis of the joint. This too would be a source of TMJ pain.