TMJ Definition and Components

TMJ dysfunction, sometimes labeled TMD, is a disharmony between the way the jaw joint works in its most unstrained position and the way the teeth occlude during those movements. There can be many causes of this disharmony. Some possible causes of this disharmony include tooth loss, restorative dentistry without properly adjusted occlusion, accidents (like whiplash), mal-positioned and/or underdeveloped cranial or jawbones, and perhaps habits like clenching or grinding the teeth. For optimal TMJ health to exist, there must be a harmony between the way the mandibular (lower jaw) condyle is positioned in the glenoid fossa (joint space) and the way the upper and lower teeth occlude (come together). If this harmony does not exist, one or more of four conditions will develop. There could be:

  1. excessive wear patterns on the teeth
  2. fracturing of the teeth
  3. loosening of the some or all of the teeth
  4. development of any or all of the TMJ dysfunction symptoms explained elsewhere in this website.

Often we will be able to recognize one or more of the first three above mentioned conditions prior to the onset of TMJ dysfunction symptoms and take steps to prevent their occurrence.

There are always two components to the temporomandibular joint dysfunction: a structural component and a stress component.

The Structural Component

The lower jaw is sort of in a sling of muscle and tendons whose job it is, in addition to opening and closing the mouth, is to position the lower jaw where ever it needs to be in order to get maximum interdigitation of the teeth. If the upper jaw (maxilla) is shifted to one side, canted up on one side, slanted (one side farther forward than the other), sloped too steeply, positioned too far forward or backward, or too high or too low, then the muscles and tendons of the lower jaw (mandible) have to move it into an eccentric and strained position for the teeth of the two jaws to come together optimally. Because of the way many nerves and blood vessels exit the skull in the area of the temporomandibular joint, this eccentric position of the lower jaw can impinge on them setting up the conditions leading to the myriad of symptoms stated elsewhere at this website.

A second structural problem, and a very common one indeed, is the loss of vertical dimension. This could be thought of as the "chin-to-nose" distance. The ideal vertical dimension can be compromised any number of ways: collapse of the dental arch due to the loss of one or more teeth; excessive wear of the teeth; orthodontic extractions; an arch size discrepancy between the upper and lower dental arch; or possibly a genetic predisposition. At any rate, this hyperflexion of the jaw joint puts pressure on the nerves and blood vessels, which exit the skull through the joint space, thereby precipitating the one or more of the symptoms associated with TMJ dysfunction.

The Stress Component

There is also a stress component to TMJ dysfunction. Actually, neurological pathways have now been identified and defined, which explain the relationship of stress to TMJ dysfunction. Often, there is a feeling of hopelessness and/or helplessness, which goes along with full-blown TMJ cases. A state of depression is a common finding. It is hard to identify which came first, "the chicken or the egg." Did the pain and frustration of not finding someone who could help cause the depression, or did the depression precipitate the TMJ symptoms.

In fact, in some instances, the symptoms of TMJ will be significantly reduced simply by removing known stressors. Because in our fast-paced society there are so many stressors, it is often difficult, if not impossible to eliminate them. A more practical approach is to learn to entrain our sympathetic and parasympathetic nervous systems at will, so that the stressors don't have the disasterous effects on our body organs and immune system. This, in fact, can be accomplished and the benefits are quite remarkable. The technique can be learned quickly.