There a few stages of TMJ Dysfunction that may or may not create TMJ pain. We will first look at a normal Temporomandibular Joint and compare it to the dysfunctions that for some of our patients, may cause pain:
Normal Temporomandibular Joints (TMJs):
The TMJs are a very complex joint, unlike all the other joints in the human body. You will see that the lubricating disc on top of the joint is concave shape both on the top and bottom ( bi-concave shape of the disc), and during the opening and closing motion the disc stays between the condyle head and the eminence. During the phase when the jaw is closed, the joint is more down and forward compared to being towards the back near the nerves and blood vessels. TMJ Pain can occur if this joint is in the incorrect position, causing inflammation in the joint space and the surrounding facial muscles.
Disc Displacement with Reduction (the disc clicks on and off of the joint head).
This can cause TMJ pain due to the improper location of the TMJ.
During this video, you can see that there are stretched out ligaments in the back of the disc, and that the disc gets loose, thus placing it in front of the joint. When the jaw opens and closes, the joint may make a clicking or popping sound. For many people this does not cause pain, but it should be understood that over time as the ligaments keep stretching the jaw can “lock” in a closed position and the condition may get worse at an accelerated rate.
DJD – Degenerative Joint Disease (torn ligaments and/or disc)
DJD or degenerative joint disease is the last few stages of TMJ dysfunction. The video shows the disc completely detached and thus the shock absorber of the jaw joint is completely removed. This may cause pain at first, and later on the condyle will eventually flatten out and change the shape and direction of jaw opening. Note that the joint disc is entirely in front of the condyle (anteriorly displaced).
When this occurs, the joint is no longer being protected by the disc, and thus the joint head starts to get a flattened shape. This becomes important in your dental health because your bite will continue to change as your jaw continues to move position with the reshaping of the bone in your jaw joint.
These videos show the basic progression of TMJ dysfunction. For many people, they can be stable with or without pain for many years. Often times however, trauma will advance the joint dysfunction from one stage to the next. Car accidents, sports injuries, and even opening to wide to fit a hamburger in your mouth all are examples of how trauma can advance TMJ dysfunction complications.