English | Español | HOME PAGE

TMJ Symptoms

Most often TMJ problems result from the simple fact that when teeth are put together, their TMJs are not in a functionally acceptable position. In fact, this is another major difference between the TMJ and all your other joints - something outside of the joint itself (your teeth) can prevent the TMJs from acquiring their best physiological position. Additionally, the sensory input to the muscles is affected by how the teeth fit together and this is the primary cause of muscle tension headaches.

The symptoms most often associated with TMD are ear and joint pain, headaches, joint noise, and uncharacteristically rapid tooth wear to name a few.

The problems associated with the joints themselves are illustrated below:

Joint Noise

Quite often, the disc is displaced to a position in front of the condyle. This results in first a "clicking" or "popping" sound. The disc at this stage is still able to slip or pop back onto the top position on the condyle during the open/close cycle.

Jaw Locking

Some people may then experience "locking" of the jaw joint. This occurs because the disc is no longer able to slip or pop back on top of the condyle during the opening or closing cycle. (It is perpetually trapped forward). Because this occurs, the mandible opens only in the first part of its motion and is not able to complete a full cycle - the person often exhibits a limited opening of their mouth.

Pain

Pain in the joint area is caused by inflammation and compression of the tissue behind the disc. That area is in red and behind the disc in the illustration above.

Muscle Tension Pain

There are numerous muscles that "power" the TMJ.

The two illustrated here are the two most frequently involved in soreness / pain.

  • Temporalis Muscle
  • Masseter Muscle

 

  

Additional problems not directly in the joints but caused by the same jaw dysfunction.

  1. Problems with the teeth.
    • Loose teeth.
    • Sore teeth.
    • Excessively worn teeth.
    • Loss of bone support around the teeth.
  2. Ear problems.
    • Hissing or ringing.
    • Ear pain, ear ache (in the absence of infection).
    • Vertigo, dizziness.

What determines who may acquire TMD and who may not?

The answer is elusive. In reality no one has an ideal bite! People without symptoms, function within an envelope of tolerance. Those with pain have tooth based jaw function that is outside their individual range of tolerance. The range or envelope of tolerance is not a measurable entity and it is different for everyone. The envelope is an arbitrary term used to help understand TMD, why it affects some and not others and the required treatment modalities.

 

Molar Fulcrums

What are causes of a less than ideal bite?

In most cases, when there is a true TMD problem, there exists what is referred to as a "molar fulcrum". The following images and narratives will attempt to explain and demonstrate this condition.

In this image a correct position for the jaw joint and teeth is demonstrated. Here the teeth make simultaneous and equal contact at the exact moment that the jaw joint is in its physiologically functioning position. The black arrows show that the force being applied to the joint is directly across the disc. Also, in this stable position, the muscles are in "neutral" (not firing), and no damaging forces exist to either the disc, the bony components of the joint, or the teeth.

This is where most TMD patients find themselves, the teeth are in a position where they make simultaneous and equal contact, but the jaw joint is forced out of a physiologically stable position. This position of the jaw joint leads to increased night grinding, increased muscular tension and damage to some or all of the following: the joint disc, bony components of the joint, teeth or the bone supporting the teeth.

In the third image the jaw joint pivots into a correct joint position with the forces now directed correctly across the disc and bony components of the joint, but the upper and lower teeth do not occlude in a stable healthy position. NOTE that the point of contact (green area) is at the last molar and therefore the term - "molar fulcrum".

Natural self protection to fit the occlusions may cause to more harm an instability of the TMJ discs

Patients with joint problems do not notice that they have this discrepancy present. The reason for this is that the muscles that control the joint position shift the jaw just before the teeth make contact. This is known as an "avoidance pattern" - the muscles move the jaw so that the teeth won't crash into each other. But, the joints suffer as they are now incorrectly positioned.

Molar fulcrums are revealed through splint therapy (see section below). During splint therapy, the muscles will relax and the "avoidance pattern" will diminish over time until the "true" occlusion (bite) is revealed.