Teeth Grinding and TMJ Disorders
What is the Temporomandibular Joint?
The temporomandibular joint connects the lower jaw, called the mandible, to the temporal bone at the side of the head. If you place your fingers just in front of your ears and open your mouth, you can feel the joint on each side of your head. Because these joints are flexible, the jaw can move smoothly up and down and side to side, enabling us to talk, chew and yawn. Muscles attached to and surrounding the jaw joint control its position and movement.
When we open our mouths, the rounded ends of the lower jaw, called condyles, glide along the joint socket of the temporal bone. The condyles slide back to their original position when we close our mouths. To keep this motion smooth, a soft disc lies between the condyle and the temporal bone. This disc absorbs shocks to the TMJ from chewing and other movements.
What are Temporomandibular Disorders?
Today, researchers generally agree that temporomandibular disorders fall into three main categories:
- Myofascial pain, the most common form of TMD, which is discomfort or pain in the muscles that control jaw function and the neck and shoulder muscles
- Internal derangement of the joint, meaning a dislocated jaw or displaced disc, or injury to the condyle
- Degenerative joint disease, such as osteoarthritis or rheumatoid arthritis in the jaw joint
A person may have one or more of these conditions at the same time.
What Causes TMD?
We know that severe injury to the jaw or temporomandibular joint can cause TMD. A heavy blow, for example, can fracture the bones of the joint or damage the disc, disrupting the smooth motion of the jaw and causing pain or locking. Arthritis in the jaw joint may also result from injury. Other causes of TMD are less clear. Some suggest, for example, that a bad bite (malocclusion) can trigger TMD, but recent research disputes that view. Orthodontic treatment, such as braces and the use of headgear, has also been blamed for some forms of TMD, but studies now show that this is unlikely.
And there is no scientific proof that gum chewing causes clicking sounds in the jaw joint, or that jaw clicking leads to serious TMJ problems. In fact, jaw clicking is fairly common in the general population. If there are no other symptoms, such as pain or locking, jaw clicking usually does not need treatment.
Researchers believe that most people with clicking or popping in the jaw joint likely have a displaced disc — the soft, shock-absorbing disc is not in a normal position. As long as the displaced disc causes no pain or problems with jaw movement, no treatment is needed.
Some experts suggest that stress, either mental or physical, may cause or aggravate TMD. People with TMD often clench or grind their teeth at night, which can tire the jaw muscles and lead to pain. It is not clear, however, whether stress is the cause of the clenching/grinding and subsequent jaw pain, or the result of dealing with chronic jaw pain or dysfunction. Scientists are exploring how behavioral, psychological and physical factors may combine to cause TMD.
TMD Signs and Symptoms
A variety of symptoms may be linked to TMD. Pain, particularly in the chewing muscles and/or jaw joint, is the most common symptom. Other likely symptoms include:
- Limited movement or locking of the jaw
- Radiating pain in the face, neck or shoulders
- Painful clicking, popping or grating sounds in the jaw joint when opening or closing the mouth
- A sudden, major change in the way the upper and lower teeth fit together
Symptoms such as headaches, earaches, dizziness and hearing problems may sometimes be related to TMD. It is important to keep in mind, however, that occasional discomfort in the jaw joint or chewing muscles is quite common and is generally not a cause for concern. Researchers are working to clarify TMD symptoms, with the goal of developing easier and better methods of diagnosis and improved treatment.
What About Grinding and Clenching?
Sometimes, pain in the TMJ can come from the teeth themselves, as opposed to the TMJ and surrounding ligaments.
Teeth grinding, for example, can become harmful if your teeth are misaligned, and certain movements cause the teeth to grind against each other, creating pain in the joint. Work or personal stress can be a source of aggressive jaw activity, according to the American College of Prosthodontists, and a general dentist, orthodontist or prosthodontist are the most qualified people to look at your teeth and determine if this is the cause.
Clenching can also cause TMJ pain, and some patients exhibit this behavior at night while sleeping. Your dentist may prescribe a clear plastic bite/night guard, fabricated to help alleviate your symptoms after a thorough diagnosis has been made.
How is TMJ Treated?
While there is no single cure for TMJ, there are different treatments you can follow that may reduce your symptoms dramatically. Your dentist may recommend one or more of the following:
- Trying to eliminate muscle spasm and pain by applying moist heat or taking medication such as muscle-relaxants, aspirin or other over-the-counter pain-relievers, or anti-inflammatory drugs
- Reducing the harmful effects of clenching and grinding by wearing an appliance, sometimes called a bite plate or splint. Custom-made to fit your mouth, the appliance slips over the upper teeth and keeps them from grinding against the lower teeth
- Learning relaxation techniques to help control muscle tension in the jaw. Your dentist may suggest you seek training or counseling to help eliminate stress
- When the jaw joints are affected and other treatments have been unsuccessful, jaw joint surgery may be recommended