TEMPOROMANDIBULAR JOINT (TMJ)

The temporomandibular joint (TMJ) is the area directly in front of the ear on either side of the head where the upper jaw (maxilla) and lower jaw (mandible) meet. Within the TMJ, there are moving parts that allow the upper jaw to close on the lower jaw. This joint is a typical sliding “ball and socket” that has a disc sandwiched between it. The TMJ is used throughout the day to move the jaw, especially in biting and chewing, talking, and yawning. It is one of the most frequently used joints of the body.
The temporomandibular joints are complex and are composed of muscles, tendons, and bones. Each component contributes to the smooth operation of the TMJ. When the muscles are relaxed and balanced and both jaw joints open and close comfortably, we are able to talk, chew, or yawn without pain.
We can locate the TMJ by putting a finger on the triangular structure in front of the ear. The finger is moved just slightly forward and pressed firmly while opening the jaw. The motion felt is from the TMJ. We can also feel the joint motion if we put a little finger against the inside front part of the ear canal. These maneuvers can cause considerable discomfort to a person who is experiencing TMJ difficulty, and doctors use them for making the diagnosis

Characteristics & Symptoms:

Both males and females can get TMJ diseases/disorders. However, 90% of those seeking treatment for TMJ are women, most between puberty and menopause. Recent research has focused attention on the relationship between sex hormones and pain. A study conducted by Dr. Linda LeResche, University of Washington in Seattle, demonstrated that women on hormone replacement therapy were 77% more likely to seek treatment for jaw pain than those not undergoing such treatment. Also, women on oral contraceptive therapy were 19% more likely to seek treatment. Evidence is emerging in support of a biological explanation for why there are more women suffering from TMJ pain.
A possible explanation is structural differences, as in connective tissues, smooth muscle, or cartilage. Several other studies find an equal distribution of TMD symptoms among men and women, yet claim that females outnumber males eight to one in seeking treatment. There is wide speculation as to why this is true. Some feel women utilize the health care system more than men do; others state that women have a lower tolerance for pain. However, since women most affected by TMD are between the ages of 18 and 40, it stands to reason that detailed scientific studies should be carried out to assess the influencing effect of female sex hormones on the development of the jaw joints and temporomandibular joint disorders. In studies with baboons, estrogen receptors were found in the females’ TMJs, but none were found in the males. Scientists are unsure whether the presence or absence of hormones makes a difference in pain, the perception of pain, or function. It is interesting to note that a past scientific study has shown that male and female mice experience pain and can respond to pain differently.
TMJ pain disorders usually occur because of unbalanced activity of the jaw muscles and/or jaw muscle spasm and overuse. Symptoms tend to be chronic, and treatment is aimed at eliminating precipitating factors. Many symptoms may not appear related to the TMJ itself. Common symptoms include:

  • Headache: 80% of patients with a TMJ disorder complain of headache, and 40% report facial pain. Pain is often made worse while opening and closing the jaw. Exposure to cold weather or air-conditioned air may increase muscle contraction and facial pain.
  • Ear pain: 50% of patients with a TMJ disorder notice ear pain but do not have signs of infection. The ear pain is usually described as being in front of or below the ear. Often, patients are treated multiple times for a presumed ear infection, which can often be distinguished from TMJ by an associated hearing loss or ear drainage (which would be expected if there really was an ear infection). Because ear pain occurs so commonly, ear specialists are frequently called on to make the diagnosis of a TMJ disorder.
  • Sounds: Grinding, crunching, or popping sounds, medically termed crepitus, are common for patients with a TMJ disorder. These sounds may or may not be accompanied by increased pain.
  • Dizziness: 40% of patients with a TMJ disorder report a vague dizziness or imbalance (usually not a spinning type vertigo). The cause of this type of dizziness is not well understood.
  • Fullness of the Ear: 33% of patients with a TMJ disorder describe muffled, clogged, or full ears. They may notice ear fullness and pain during airplane takeoffs and landings. These symptoms are usually caused by Eustachian tube dysfunction, the structure responsible for the regulation of pressure in the middle ear. It is thought that patients with TMJ disorders have hyperactivity (spasms) of the muscles responsible for regulating the opening and closing of the Eustachian tube.
  • Ringing in the Ear – Tinnitus: Because of a complex neurological interaction between the TMJ joint and the facial and vagus nerve, 33% of patients with a TMJ disorder experience noise or ringing (tinnitus). Of those patients, half will have resolution of their tinnitus after successful treatment of their TMJ.

Other symptoms include:
facial pain; jaw joint pain; often in combination with neck, shoulder, back pain and/or headachespopping, grating or clicking sounds with movement of the jaw jointpain in the joints of the face when opening or closing the mouth, yawning, or chewingswelling on the side of the face and/or moutha bite that feels uncomfortable, “off,” or as if it is continually changinglimited opening or inability to open the mouth comfortablydeviation of the jaw to one sidethe jaw locking open or closed

What are TMJ disorders, and how are TMJ disorders caused?
TMJ disorders are a group of complex problems of the jaw joint. TMJ disorders are also sometimes referred to as myofacial pain dysfunction and Costen’s syndrome. Because muscles and joints work together, a problem with either one can lead to stiffness, headaches, ear pain, bite problems (malocclusion), clicking sounds, or locked jaws. The following are behaviors or conditions that can lead to TMJ disorders.

  • Teeth grinding and teeth clenching (bruxism) increase the wear on the cartilage lining of the TMJ. Those who grind or clench their teeth may be unaware of this behavior unless they are told by someone observing this pattern while sleeping or by a dental professional noticing telltale signs of wear and tear on the teeth. Many patients awaken in the morning with jaw or ear pain.
  • Habitual gum chewing or fingernail biting
  • Dental problems and misalignment of the teeth (malocclusion). Patients may complain that it is difficult to find a comfortable bite or that the way their teeth fit together has changed. Chewing on only one side of the jaw can lead to or be a result of TMJ problems.
  • Trauma to the jaws: Previous fractures in the jaw or facial bones can lead to TMJ disorders.
  • Stress frequently leads to unreleased nervous energy. It is very common for people under stress to release this nervous energy by either consciously or unconsciously grinding and clenching their teeth.
  • Occupational tasks such as holding the telephone between the head and shoulder may contribute to TMJ disorders.