Causes of TMJ
Statistics indicate that the vast majority of TMJ problems are caused by trauma. By trauma, we mean an injury as obvious as a blow to the jaw with a fist or something as subtle as a whiplash injury from a car accident that causes direct trauma to the head or jaw.
The most common forms of trauma that cause TMD are:
- Whiplash (cervical acceleration/deceleration)
- Air bag deployment
- Opening the jaw too wide
- Bad bite (malocclusion)
- Ligament laxity
- Systemic diseases
Whiplash (Cervical Acceleration/Deceleration)
Whiplash injuries often damage the soft tissue in the neck, back and TMJs. Usually these injuries happen when a car is hit in the rear. The violent motion of the head being thrown from a still state backwards and then forwards again often causes the mouth to be forced open. This produces stretching and/or tearing of the ligaments and connective tissues in one or both TMJs, and possibly bleeding and displacement of the disc in the TMJ. Common complaints after a whiplash injury include neck pain, neck stiffness or difficulty in turning the head, headaches (especially where the neck attaches to the head), TMJ pain, limited ability to open the mouth, TMJ noises, face and/or ear pain, change in bite, dizziness, visual changes (such as light sensitivity or blurry vision) and swallowing difficulties or hoarseness.
Air Bag Deployment
While air bags have undoubtedly saved lives, they have also been implicated in causing TMJ problems. Patients who have been injured with air bags often experience one or more of the following symptoms: burned or abraded skin on the chin, face or nose; almost immediate TMJ pain; swelling of the TMJs; limited mouth opening; neck pain; and change in the dental occlusion (bite).
Opening the Jaw Too Wide
All joints have limitations to movement, and the TMJ is no exception. If you open wide for a long time or if your mouth is forced wide open, ligaments may be torn, swelling and bruising develop and disc dislocation may occur.
Bruxism is the abnormal grinding of the teeth. Bruxism usually occurs during sleep, which is why many people don’t realize they are doing it. But when grinding continues, TMJ problems may develop. An indication that a person is grinding their teeth in their sleep is sore jaw muscles when waking. Minimally, bruxism may produce muscle pain, tooth sensitivity or worn teeth. In some cases, the pressure to the TMJ from constant grinding of teeth leads to ligament injuries, which might cause the disc to dislocate.
Bad Bite (Malocclusion)
A bad bite, or malocclusion, may be produced by poor development of the jaws, removal of teeth without replacement, a high dental restoration, a poor fitting denture or partial denture, or a displaced TMJ disc.
Some dentists feel that orthodontic treatment, or braces, might be a cause of TMJ. By moving teeth with orthodontic appliances, malocclusion is produced during treatment. That’s probably why many people undergoing orthodontics report sensitive teeth, pain in the jaw muscles or even bruxism. However, there is no scientific proof that orthodontic treatment produces TMJ problems, particularly once the treatment has been completed.
People who appear to be double-jointed suffer from a problem termed ligament laxity. When this occurs, a joint appears to be double – or loose. This does happen to the TMJ. Ligament laxity is a fairly common problem in active young women who suffer with TMJ problems and, often, injuries to other joints.
Stress has many effects on our bodies: some good and some bad. Physiological changes can produce muscle tightness and pain. When a person is subjected to chronic stress, these physical changes may produce harmful effects. When it comes to TMJ problems, stress is like throwing gasoline on a fire. The gasoline doesn’t produce the fire, but it does make it worse. Similarly stress intensifies TMJ problems. Muscles tighten, teeth clench, abnormal pressure is forced against the TMJ disc, and if the ligaments are weak or if the patient is one that has ligament laxity, the disc may dislocate.
Various diseases can cause or aggravate TMJ problems. Immune disorders, such as rheumatoid arthritis, psoriatic arthritis and systemic lupus erythematosus, can produce inflammation in the TMJ. Additionally, viral infections, such as mononucleosis, mumps and measles, can cause damage to the surfaces of the TMJ, which can lead to an internal derangement.
There are a number of other pain disorders that are often confused with TMJ because they involve pain in the jaw. Most common among these are:
- Temporal Tendinitis
- Ernest Syndrome
- Occipital Neuralgia
- Trigeminal Neuralgia
- Atypical Trigeminal Neuralgia
- Atypical Face Pain
- Neuralgia Inducing Cavitational Osteonecrosis (NICO)
Temporal Tendinitis – The “Migraine Mimic”
Temporal tendinitis has been called “the migraine mimic” because so many of its symptoms are similar to migraine headache pain. It is characterized by TMJ pain, ear pain and pressure, temporal headaches, cheek pain, tooth sensitivity and neck and shoulder pain. Treatment consists of injecting local anesthetics and other medications, a soft diet, applying moist heat, using muscle relaxants and anti-inflammatory medications, and physiotherapy. In very rare cases (less than 4%), surgery may be needed.
This TMJ-like problem involves a tiny ligament structure that connects the base of the skull with the mandibular or lower jaw. If injured, the structure can produce pain in the face, head, neck, temple, ear, cheek eye, throat and/or TMJ. Treatment of Ernest Syndrome, which is successful about 80% of the time, consists of injections of local anesthetic and medication (like cortisone or Sarapin), physiotherapy and, at times, the use of an intraoral splint.
This disorder is characterized by pain radiating to one or both sides of the head, temples, cheek and forehead and particularly pain above and behind the eye.
Also known as tic douloureux, this is a disorder of the trigeminal, or fifth cranial nerve. It is characterized by sharp electrical pain, which lasts for seconds. The pain is triggered by touching a specific area of the skin, as when washing, shaving, applying makeup, brushing the teeth, kissing or even from exposure to cold air. The pain is often very severe.
Atypical Trigeminal Neuralgia
In contrast to the typical type, atypical trigeminal neuralgia produces constant pain that increases or decreases in intensity. There are trigger zones, but there is also an area of dull aching. A common cause of this disorder is trauma, especially after a surgical incision or blow to the face. (June: how is it treated? does it go away or is it chronic? what do you do for it?)
Atypical Face Pain
While the same trigeminal nerve is involved in atypical face pain, in this case the facial pain seems to affect people who are under a tremendous amount of stress or have a history of psychiatric problems.
Neuralgia Inducing Cavitational Osteonecrosis (NICO)
Also known as osteocavitational lesions or Ratner’s bone cavities, this disorder produces pain similar to that of typical and atypical trigeminal neuralgia as well as referred pain patterns. There are trigger areas for the pain, which, in this case, develop directly over areas of dead bone. Generally, the lower jaw is affected more often than the upper jaw.