What is the temporomandibular joint?

The temporomandibular joint (TMJ) is located in front of your ears and is what allows your jaw (mandible) to move; in fact, the TMJ is the only movable joint in the skull. It is a joint that both hinges (opens and closes the mouth) and glides (slides the jaw down, forward and side-to-side). There are actually two joints, one on either side of the jaw, but they move and function as one.

The TMJ is a synovial joint, meaning that it holds two bones together (in this case the temporal bone and the mandible) with a tough outer fibrous capsule and ligament. It also contains an inner layer that secretes synovial fluid, which acts as a lubricant to reduce friction when the jaw is moving. The two bones that are held together by the TMJ don’t actually touch in a healthy joint, because there is a disc of collagen tissue in between to cushion them.

What can go wrong with the TMJ?

As with any moving part, there are many things that can go wrong with the TMJ, and they are commonly referred to under the umbrella term Temporomandibular Joint Disorders (TMD).

• ”Clicking” or “popping” – this is a sign of disc displacement. This is caused by the ligament of the TMJ being stretched or damaged, allowing the disc to shift forward and/or sideways when opening your mouth. If the disc returns to its normal position when the mouth closes, it is called disc displacement with reduction. You may have no symptoms other than noticing the sound, or you may experience headaches, muscle pain, a bite shift, toothache or a feeling of restriction when opening or closing your mouth. Treatment can include medications, exercises and/or jaw manipulation, oral appliance therapy and, rarely, surgical treatment. If you only notice the “clicking” or “popping” with no pain or restriction of movement, no treatment is necessary other than monitoring the status over time.

If the condition worsens, it’s important that you begin treatment quickly so that it doesn’t progress to disc displacement without reduction, meaning that the disc remains stuck forward of its normal position and can no longer slip back into place. If this happens, the joint will have restricted ability to move and you may experience pain in the TMJ/ear area, bite changes, and limited mouth opening (sometimes becoming “locked”) resulting in difficulty eating. Treatment options are the same as with disc displacement with reduction (with surgery becoming more likely), but the displacement becomes more difficult to resolve and the damage may be permanent. The only way to confirm a diagnosis of disc displacement without reduction is with an MRI. Time is of the essence when it comes to unlocking a displaced disk, so call right away.

• Grinding your teeth (bruxism) – grinding your teeth at night is often a sign of obstructive sleep apnea (OSA), because you’re unconsciously trying to get a better airway. If OSA is suspected, the next step is a referral to a sleep specialist, who will order a sleep study to determine whether you have sleep apnea. Depending on the severity of the apnea, treatment can include oral appliance therapy, positional therapy or a CPAP machine., with surgery reserved as a last option.

• Myofascial pain – this type of pain is caused by repeated stress on muscle fibers that irritate the nerves connected to the muscle. The muscle then develops hypersensitive spots called trigger points, which can show up as pain in the area of the muscle or as referred pain somewhere else. Trigger points in the head and neck area can cause tension headaches, tinnitus (ringing in the ears), eye twitching and tears, TMJ pain and torticollis (painfully twisted and tilted neck). Treatment focuses on decreasing repetitive strain and typically includes physical therapy (stretching, posture training, massage, heat and ultrasound), trigger point injections and medications.

• Arthritis – like any other joint in the body, the TMJ can develop arthritis. The symptoms may include a “grinding” or “crunching” sound in the joint (caused by breakdown of cartilage, changes in the bone, and degeneration of the synovial tissues – i.e., wearing a hole through the disc), along with pain. The treatment can include anti-inflammatory medication, pain medication and use of a mouth guard.

• A dislocated jaw and/or other traumatic injury to the jaw can cause serious internal damage to the TMJ, and requires immediate medical attention to lessen the odds of permanent impairment.

What should I do if I think I have TMD?

Contact a dentist with experience in treating temporomandibular disorders. The dentist will do an oral exam to rule out other possible dental causes of your symptoms and prescribe the appropriate treatment plan for you.

Then, follow the treatment plan! Many TMJ issues can resolve through conservative treatment, home care and behavior modification, but complicated or long-term TMD rarely (if ever) “just goes away” by itself.