Injury to the
temporomandibular (TM) joint 
most commonly occurs when
too much stress is placed on the joint by:
- Chewing hard or chewy foods.
- Bruxism
(grinding or clenching the teeth) over a period of time.
- Dental
procedures that require the jaw to be held open too wide for a long
time.
These stressors can cause the articular disc to shift out of its
normal position (disc displacement). Because this disc cushions the joint
between the jawbone (mandible) and the skull, displacement can result in pain
and locking of the joint.
A blow to the jaw, TM joint dislocation, or jaw fracture can also
result in TM disorder symptoms.
