What is TMJ?

What is TMJ?

TMJ is an abbreviation for temporomandibular joint dysfunction.  The temporomandibular joint is the joint that connects your mandible (lower jaw) to your skull.  It is located just in front of your ear.  When the jaw is misaligned it can cause a wide array of symptoms which is why tmj dysfunction is referred to as a syndrome, meaning a collection of symptoms. Symptoms include jaw pain, headaches, tooth pain, neck pain, sinus pain, eye pain, visual disturbances, etc. (see Associated Medical Disorders).

The dental profession as a whole is very poorly educated on TMJ.  Generally, most dental school curriculums give TMJ very little attention. The schools do not know “what is TMJ”.

TMJ treatment is further complicated in that there is a very long standing controversy as to the cause, and subsequently what comprises proper treatment (iccmo_position_paper).  The first camp believes that TMJ is psychosomatic- stress induced.  The other camp believes that it is due to a misaligned jaw.  If you believe the first, then the proper treatment is psychotherapy, stress management, night guards, and physical therapy.  If you believe in the latter, then the preferred treatment is jaw repositioning with appropriate appliances designed  to align the jaw. My clinical experience has been that 95% of the cases fall into the latter classification.

I believe this controversy continues in large part due to the fact that dentistry is based on structure, not function.  Dentistry does not have a functional model of ideal occlusion (see New model of Occlusion), only a structural model (class I occlusion).

What causes TMJ?

I believe most cases of TMJ are caused by misaligned jaws, not stress.  When the jaw is misaligned one handles stress poorly.  There are a number of situations that can cause a person to develop a misaligned jaw: deviated septum, genetics, allergies, poor orthodontics, poor dental work, missing teeth, etc.

How do you diagnose TMJ

Typically, upon examination of a TMJ patient I find that there is a substantial vertical height deficiency from inherited structure which necessitates that the lower jaw be pulled back in order to get the teeth together, thus causing compression in the TMJ and subsequent TMJ pain.  Clinically this is determined by 1)feeling the excess compression in the TMJ by sticking your finger into your ear lightly and biting down.  On a normal person the condylar head is not palpable.  (2)Have the patient count from sixty to seventy.  Often with a misaligned jaw the lower jaw thrusts with “s”  sounds (not ideal). (3) Have the patient open wide and close on a tongue blade (stick).  Most patients with TMJ bite significantly more forward with the tongue blade that in their normal bite.  The tongue blade keeps the front teeth from hitting ( hitting the front teeth would normally cause the jaw to bite back- compressing the TMJ).  (4) Take x-rays or MRI if necessary.

x-ray of TMJ

x-ray of TMJ



Together this information very quickly can determine if the TMJ is compressed.

TMJ Treatment:

Fixing the compression will get rid of symptoms and joint pain rapidly. This is done by inserting an appliance (twin block appliance pictured) in the mouth that builds the back teeth taller so that the jaw does not close up into the joint so far (see sample picture).  In picture overbite has been eleminated and the lowTMJ twin block applianceser jaw is slighly forward of the upper. Eventually the case will be stabilized in the final determined therapeutic positon by orthodontic eruption of the back teeth.

11 Responses to What is TMJ?

  1. Cynthia Powell says:

    Before recent orthodontic treatment, I had crowded incisors and a significant overbite I attributed to decades of clarinet playing. My posterior teeth had a strong, pain-free bite, and my TMJs only clicked/popped rarely when reclining, like in the dental chair.

    Because of a mis-diagnosis (“No TMJ abnormalities detected”) my posterior teeth are now poorly aligned, and I have a lot of jaw pain. Doing the finger-in-the-ear test, I can feel about 1/8 inch motion on the left side, and about 1/4″ – 1/2″ motion on the right side. Additionally, my #19 tooth required a root-canal re-do (braces related).

    My endodontist said no chewing on the left side, and no more braces until 2/2014; and my general dentist doesn’t want to replace the crown on #19 until my teeth are properly straightened. So I’m wondering what can be done to reduce jaw pain, without disturbing the #19 tooth, until I can get my teeth properly straightened. Oddly enough, even though it is harder to hold a clarinet mouthpiece between my teeth (top incisors pushed back a lot), the muscle memory position of the embouchure (lower jaw forward) gives TMJ pain relief.

    Is TMJ treatment possible right now given the above parameters?

    • Dr. Jennings says:

      Yes, TMJ treatment should be done before continuation of orthodontic treatment and before the permanent crown is done. Dr. J

  2. Deborah Walton says:

    I have had TMJ for 8 years now and have experienced surgery on both sides of face. I have just recently had another MRI and they are telling me that I am facing surgery again. I am having discomfort and a lot of headaches due to the right side of disc looks like hamburger meat again and left side is on its way as well. Can you help? The surgery was brutal the first time and not looking forward to another one. Thanks.

    • Dr. Jennings says:

      Deborah: Sorry for the delayed response, your inquiry was misplaced. I have treated many cases that had prior surgery. Generally, they are a bit more unstable than non-surgery patients, but they do respond. The problem with surgery is that it does not decompress the jaw joint. Dr. J

  3. ouafaa says:

    Hi dr jennigs,
    My problem started one day when i noticed swelling of the right side of my face , mainly on the jaw line. I went to so many doctors, dentist, and i have been told that it is not serious, or maybe i lost weight but just on one side, i v been that i ve been told that i have tmj but it was based on no diagnosis , it s just i was not convinced.
    I do grind my teeth at night, i have missing teeth, on the upper right and lower left. I did a panoramic x-ray and my jaw doesn t look even , one side is wider than the other . And the swelling is not going away. I just don t know what to do and i feel like no one that i went to see for this swelling ,really took it serious. Thank you.

    • Dr. Jennings says:

      I’ve seen a number of TMJ cases where swelling is quite severe (can be caused by elevated substance P). Missing teeth often contributes to the bite getting off. The bite can be off without there being any symptoms in the jaw joint area.

  4. Pingback: Dr. Dwight Jennings: TMJ, Jaw Pain, & Substance P - #179 - Bulletproof

  5. Kelly Matovich says:

    Hi My Name is Kelly,
    I’ve had partial seizures for the past 7 years. Just a bit of background, I only get my seizures one or two days out of every month, related to my menstrual cycle. Recently, I approached my dentist asking him for options to help me with my TMJ because I thought maybe the TMJ was causing me to have seizures. He gave me a couple options: 1: create a mouth guard to correct and adjust my bite (very expensive and not covered by HC).
    2: Inject botox into the muscles around your jaw to paralyze them. (not as expensive but not permanent).
    I ended up trying the botox and I thought it was working until the last couple days. I track my episodes regularly and I was expecting to have them somewhere between Dec 16th -18. But instead it just pushed them to 22 days later. Any help or advise you could provide would be greatly appreciated. Im in British Columbia, Canada. Thank you,

  6. SriHarsha says:

    Hi Dr.Jennings,
    You mentioned in the article that, deviated septum may cause jaw misalignment which is my kind of situation. I have misaligned jaw and deviated septum.
    So in order to proceed some kind of splint therapy, do I need to correct the deviated septum first?
    If I don’t correct the deviated septum does any kind of treatment don’t produce results?
    Waiting for your reply.


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