Causes
In order for you to open your mouth and operate your jaw in the way that
it should, your left and right TMJs must work in unison. If the movement
of both of these joints isn't coordinated, the disc that separates your lower
jaw from your skull can slip out of position, and problems will result. Dislocation
of your TMJ may take place if your mouth is forced to open rapidly or too widely.
In addition, muscle pain and tightness around the jaw can often come from
muscle overuse as a result of clenching or grinding the teeth (bruxism)
brought on by psychological stress or overuse. Extreme jaw clenching can also
lead to pain over the temples. This occurs because the muscles that control
jaw movement are also attached to a nearby bone of your skull. Excessive gum
chewing or forceful biting, such as cracking nuts in your teeth, may also strain
the TMJs and cause pain.
Some additional and less common ways of developing temporomandibular joint
problems include:
- ankylosis, which is loss of joint movement resulting from a fusion of bones
within the joint or calcification of the ligaments around it
- arthritis
- certain inherited facial characteristics that produce misalignments
- congenital abnormalities where the top of the jawbone doesn't form or is
smaller than normal
- dental conditions such as a high filling, a tipped tooth, or teeth displaced
due to earlier loss of other teeth
- developmental abnormalities such as in some children where the top of the
jawbone may grow faster or for a longer time than normal. Congenital and developmental
abnormalities are rare, but can cause facial deformities and misalignment
of the upper and lower sets of teeth.
- hypermobility (looseness of the jaw), when the ligaments that hold the joint
together become stretched
- internal derangement, where the disc inside the joint lies in front of its
normal position
- structural abnormalities of the temporal joint