Dr. Rick Bonomo

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By Dr. Rick Bonomo

Appeared in the Daily American, April 1, 1997

TMJ STANDS FOR "Temporomandibular Joint."
You may have heard someone say, "I have TMJ." Well, of course, everyone has TMJ -two of them, one on each side of the jaw. The most recent term for the condition is "Temporomandibular Disorder" or TMD.
The symptoms were first described by an Ear Nose and Throat doctor in the 1930's and was called "Costen's Syndrome." He described a group of patients who had pre-auricular (in front of the ear) pain, clicking and popping of the joint, tinnitus (ringing in the ear), and other symptoms. As with many other attempts to define the condition he included findings that were not seen with all patients (e.g. tinnitus) and this lead to much confusion.
The confusion persists today. The National Institute of Health recently conducted a conference to attempt to come to a consensus on treatment since it has become a multi-million dollar health care item. Members of all heath care disciplines who are involved with the treatment of TMD participated. Unfortunately, no consensus was found and the controversy continues. The conference leaders published statements that have prompted heated debate in the professional literature. These include the following:

1.	There are significant problems with present diagnostic classifications of TMD, because these classifications appear to be based on signs and symptoms rather than etiology.
2.	The preponderance of data does not support the the superiority of any method for initial management of most TMD problems...
3.	The efficacy of most treatment approaches is unknown...
4.	There are no data to support commonly held beliefs...
The complete text and abstract are available at no charge at 1-888-NIH-CONSENSUS (644-2667)

Illustration. The anatomy of the joint is as follows: The condyle or top of the lower jaw articulates with the glenoid fossa directly in front of the ear. The fossa is part of the temporal bone. In between these two bones is a disc that acts like a cushion. The disc normally moves with the condyle when the jaw opens. As the jaw opens, the disc slides forward, and when the jaw closes the disc moves back with it. Behind the condyle is the retrodiscal pad, which contains the nerve that perceives pain in the joint.
When you yawn your jaw opens like a hinge. When you bite with your front teeth the lower jaw must slide forward to bite (try it). To bite with the molars on the right side, the left condyle advances forward more than the right. This is the simplest explanation. Not mentioned are the effects and limitations imposed by the angles of the cusps of the teeth...and on and on. A whole school of knowledge exists called "gnathology" which studies the movements of the jaws as they relate to the teeth and joints. Unfortunately, even though a tremendous amount of research has been expended, gnathologists cannot offer a cause and effect relationship between the teeth, the bite and joint pain. One thing that is often observed with the loss of all or some back teeth: excess pressure is placed on the joint due to the lack of support from the back teeth.

Normal

Slightly Displaced

Advanced Displacement

It is very common for the disc to move independently from the condyle following trauma to the chin or as a consequence of systemic disease. As the jaw is forced back the ligaments surrounding the joint become stretched, and the disc may be torn. The disc is then displaced forward and toward the midline by the lateral pterygoid muscle. When the jaw is closed the disc is displaced. When the jaw opens the disc "clicks" back into the proper relation to the condyle. When the jaw closes a "reciprocal click" occurs. Patients may or may not report pain. A conventional X-ray will show decreased joint space indicating that the disc is not where it belongs.
When this action continues for a long time the retrodiscal pad stretches and it becomes impossible to get the disc where it belongs, and jaw opening may be restricted. This is termed "Closed Lock." As the pad becomes stretched even further, further opening can occur. All this dysfunction may lead to muscle spasms and pain in the muscles. The other source of pain is pressure by the condyle on the retrodiscal pad and nerve.
The next stage observed is perforation of the pad or disc and bone-to-bone contact of the condyle and fossa. The body's reaction to this is inflammation of the bone and resorption (or melting away) of the bone of the condyle. This is the first time bony changes are seen on conventional X-rays. This finding lead to operations on the joint (high condylectomy), which decompressed the joint, severed nerves, interrupted pain, and allowed bony remodeling of the condylar head.

The click was the source of an enormous amount of speculation. It was very convenient to attribute the pain to this click since many people who had pain had the click. What wasn't acknowledged was that many people who have clicks also have no pain. Imaging of this "pathology" was done by arthrograms, whereby dye was injected into the joint space and X-rays were taken. Now an MRI is taken to image the disc. This knowledge lead to joint operations to repair the disc and place it in the correct relation to the condyle. Many people have been successfully treated in this way, but the indications for this operation are rare and only undertaken after conservative treatments have failed. "Blind" condylotomy where a bony cut was made below the condyle was done which allowed the condyle to find it's own new position has also had some success. The least invasive method to repair the disk is by arthroscopy.
The fact that many people who have joint pain also are under stress prompted research to find whether stress caused joint pain. Often overlooked was the fact that chronic pain will cause stress. Psychotherapy and tranquilizers have been used to help patients deal with chronic pain.
It has been observed that a large number of middle-aged females report joint pain but a hormonal cause has also not been proven.
It is noted that many people with crooked teeth have joint pain, and many people are treated with braces to treat the pain. Also, most people with crooked teeth do not have joint pain.
The NIH conference recommended that "reversible" or non-invasive treatments be tried first. Frequently observed are patients who report pain and who grind their teeth at night or during the day. They are treated with a night guard or occlusal splint often with good results by interrupting the pain/muscle spasm/ pain cycle that can occur. Physical therapy has helped many who have muscular pain associated with the jaws.
Mandibular positioning devices, where the mandible is placed in a splint that holds the lower jaw slightly forward and slightly open, may relieve pressure on the retrodiscal pad and offer relief.
The biochemical events that take place in an inflamed joint are now being brought to light. TMJ arthroscopy with lavage of the joint space to remove irritating chemicals caused by inflammation has had great success. Dr. Joe McCain, formerly of Western Pennsylvania, pioneered this technique.
It is strongly recommended that prior to the start of any treatment the patient fully understand not only the diagnosis but also exactly how the course of treatment may help and the possibility that it may fail. A complete evaluation by a qualified practitioner is essential to rule out systemic causes of face and joint pain such as neurological disease or rheumatoid arthritis.