by Elyse M. Rogers


It may go by different names, but whatever you call it, temporamandibular joint syndrome is a condition very much in the medical news to­day. Probably best known by its initials, TMJ, it’s a condi­tion yuppies brag about, old­sters worry about and every­one else talks about. The temporamandibular joint is the one located right next to the ear on which the lower jaw hinges.

Those who complain of TMJ say they have “popping” or “crackling” in the jaw when they open and/or close their mouths. Other symptoms can be both multiple and vague, ranging from headaches, neck and shoulder pain, to dif­ficulty in opening the mouth and chewing.

TMJ is in the news a lot in the U.S., but to find out what was going on in Japan I talked with Y. Kobayashi, D.D.S., Ph.D, Professor and Chairman of the Department of Partial and Complete Denture, Tem­poramandibular Joint and Fa­cial Pain Clinic of the School of Dentistry at the Nippon Dental University. Whew! Got all that?

To assist in our English-language discussion. Dr. Haruo Ishikawa, an orthodontist, kindly joined us. Both dentists spent time in the U.S. Dr. Kobayashi spent time at the University of Michigan and Dr. Ishikawa at the University of Washington in Seattle. Dr. Ishikawa’s English is very good; Dr. Kobayashi speaks creditable English, but is “a bit rusty,” he told me.


I was very pleasantly sur­prised when I walked into the Nippon Dental University in Iidahashi. It is a spanking new building (completed in Octo­ber of 1987), with spacious wailing areas, window walls, silent elevators that glide up seven floors and lots of good equipment.

The university itself has an 80-year history and is the second oldest school of its type in Japan. Prior to its new facilities, the hospital was lo­cated about two blocks away. That old area now is under construction for dormitories and buildings for the universi­ty.

The outpatient clinic is simi­lar to most, but since it is a private university, open clinic hours are a bit longer—from 9 a.m. to 5 p.m. Walk-ins arc welcome anytime but new­comers arc preferred in the morning or early afternoon. To see specialists, such as Dr. Kobayashi. afternoon hours, by appointment only, are the rule.

The hospital is very Japa­nese in both ambience and services. I saw no English-language signs or forms and everyone I spoke to (in the reception area) knew only Japanese. But it has every type of dental service available— from rouline dental care to Dr. Kobayashi’s special services and orthodonture, etc.


Despite the fact that TMJ has been around for more than 200 years, according to Dr. Kobayashi, scientists still do not know for sure what causes the problem. There are theories, however, and the two major current ones are as follows:

1) That TMJ is caused by some type of occlusion problem. For example, the person’s teeth and bite are out of alignment, or a filling is too high, or there is some other problem that interferes with the correct opening and closing of the

2) That the problem is psychological. This doesn’t necessarily mean that the patient who has TMJ has gone bananas, but it could mean that the TMJ person has been under a great deal of stress or even has symptoms of depression or other emotional problems.

Stress is one of the major causative factors that seems to bring on TMJ symptoms and Dr. Kobayashi said, “TMJ is more common in Tokyo, because there’s lots of stress.”

There is also some feeling that patients who have had orthodontic treatment may he more susceptible to TMJ because they have had extensive work on the mouth which could affect the jaw.


Because the symptoms of TMJ can be vague, it is often difficult to know for sure that the patient’s complaints are actually caused by a jaw problem. Obviously there can be other causes of headaches, neck and/or shoulder stiffness, and even of facial pain.

In diagnosis the following may be used:

1) Examination. A physical examination with palpation and observation by a dentist skilled in TMJ problems is important.

2) Patient history. The patient’s description of his symptoms is important. Some dentists believe that there are two symptoms—pain and limited jaw movement—that must be present in order for a diag nosis of TMJ to be made.

In any event, finding out the exact symptoms and how long they have occurred, and if there are other physical ailments, etc, is important.

Oftentimes, according to Dr. Kobayashi, patients have symptoms for many years before coming to the clinic. “I’m treating one patient who said he had symptoms of TMJ for 15 years before I saw him,” he told me. His coming to the doctor was probably as much because of the new pub­licity about TMJ as because his symptoms got so much worse.

Although that can happen. One woman I read about in the U.S. had problems with opening and closing her jaw (it would get stuck open or shut) until it finally locked itself shut. She was one of the ones who had surgery, and she is now improved, but still wears a night-time mouth-guard to keep her jaw relaxed while she sleeps.

3) Tests. There are many different types of tests to aid diagnosis, including X-rays. EMG (electric myography, which indicates muscle activity around the joint), wireless tele­meter, etc. The wireless tele­meter is an interesting piece of equipment. It is a system whereby the patient can wear a belt-type of monitoring sys­tem in his sleep, to determine his sleep habits and how they effect his physiology.

Muscle activity, heart rate, respirations and teeth and jaw movement can be monitored at a remote station while the patient sleeps. As you can imagine, this gives very im­portant data to the doctor in charge.

I should just mention that Dr. Kobayashi has done an experiment using the wireless telemeter which has proven most interesting. The idea was to see if an occlusal problem could cause sleep disorders. In other words, if a filling is too high or there is some other jaw/mouth disability, this could cause sleep disorders and other problems as well.

From the summary report published in the Journal of Oral Rehabilitation in April of this year, such occlusal interference could “initiate sleep disorder, alter the func­tion of the autonomic nervous system, heighten emotional stress, and thereby increase the frequency and degree of bruxism (tooth grinding). It may also cause displacement of the condyle and increase the ten­sion of the muscles.”

Wow! I don’t know about you, but I sure hope I don’t have malocclusion when I sleep—I’ve got enough prob­lems to deal with when I’m awake.

4) Psychological tests. Ap­proximately 32 percent of patients who come in for TMJ treatment have psychological problems, so psychological testing is often part of the   —initial testing.


I was pleased to hear Dr. Kobayashi is very conservative in his treatment of TMJ, since all my research suggests the conservative mode is best here.

The main conservative treat­ment is to provide some kind of mouth splint or brace to TMJ patients. It’s interesting that this apparatus is both a treatment and a diagnostic tool. “If the patient responds to the treatment by having his/her symptoms relieved, we know it truly was a TMJ problem,” the doctor tells us.

If the patient doesn’t re­spond to treatment, but all other tests point to a TMJ problem, other types of splints are tried. “We have many dif­ferent types of splints for different types of particular problems or even for individual differences,” Dr. Kobayashi explained, “Sometimes it takes a bit of time to get the exact right one.”

Surgery was a treatment often discussed and tried in the U.S., but Dr. Kobayashi feels this should be used only as a last resort. In his more than 20 years of treating TMJ patients, he has only resorted to surgery twice. In America too.  the trend  is  away from surgery, towards more conser­vative or “non-invasive treat­ments.” Surgery for TMJ, it seems, often creates more problems than it solves.

Biofeedback is another tech­nique used in the treatment of TMJ, mainly to help the patient relax the muscles around the temporomandibular joint and to help him control stress and tension.

Exercises are also often prescribed. I was interested particularly in these because I’d heard a lot about them in the states. There are several kinds of exercises but several are involved with working against an opposing force.

For example, you place your hand or fist under your chin and then try to open your jaw. In the same manner, you can open your mouth and grasp your chin with your fingers and try to close your mouth again while your hand tries to keep it open. Also, just moving your jaw up and down (opening and closing your mouth) in as straight a line as possible (don’t move the jaw sideways at all) is good exer­cise. To make sure you’re moving it in a straight line, look in the mirror while you practice.

Painkillers, sedatives and muscle relaxants may be pro­scribed. Dr. Kobayashi emphasizes that beginning treatment is aimed at relieving symptoms and giving the jaw a rest. Therefore, the diet should he a soft one with no large or chewy foods. He suggests that more difficult foods be cut into very small pieces to make it easier for the jaw. Chewing gum too, should be avoided. After the symptoms have subsided, then exercises can be started and normal chewing resumed.

Unfortunately, treatment for TMJ rarely produced dramatic results. It takes anywhere “from two weeks to ten years” to cure TMJ, according to Dr. Kobayashi.


Studies have been done in the U.S. and in other countries which indicate that about 50 percent of the population (or more) have some symptoms of TMJ. For example, about 40 percent report they have “clicking or popping sounds” when the jaw opens. But that doesn’t mean such a large group will need treatment.

Some may go from the simple clicking and popping to more serious problems of difficulty in opening and closing the jaw and of pain, but many will never get any worse. Dr. Kobayashi says they have conducted smaller studies in his clinic and they also have found that more than 50 percent of the patients do have some symptoms of TMJ.

I mentioned that orthodon­tic treatment may be a cause of eventual TMJ problems. There is no definitive data on this one way or another as yet. But according to some ortho­dontists I’ve talked with, TMJ problems can usually be pre­vented after orthodontics if the orthodontist plans carefully to make sure the proper relation­ship between teeth, bite and jaw are maintained.

As one orthodontist put it. “It’s not enough to just straighten the teeth so the re­sult looks good for awhile: rather it is the long term health of the whole mouth and head that is the primary goal of good orthodonture.”

With that in mind, it might make sense to ask the ortho­dontist you work with (if you or your child gets braces) what steps he/she is taking to avoid the TMJ problem later. As more becomes known about TMJ. more general dental practitioners will know more about the condition. But at this time, if you feel you have a TMJ problem, you’ll probably want to go to someone like Dr. Kobayashi who under­stands this rather complicated syndrome.

At Nippon Hospital, you can simply walk into the out­patient clinic for general dentistry problems, but to see Dr. Kobayashi or others in his de­partment, you should call and make an appointment. The wait after you arrive is “not too long” according to the doctor Since this is a Japa­nese establishment, if you can’t speak the language, have someone who docs speak Japa­nese make the appointment for you. It might help if that per­son accompanied you to the hospital as well, since getting registered and finding the right department could be dif­ficult.

According to the doctors I talked with, they see “very few foreigners” at Nippon Dental.

The hospital is easy to find as you almost fall into it after exiting at Iidabashi. From the JR Iidabashi station, go out the exit toward Shinjuku, turn left and when you reach the first corner you’ll see a sign on the corner opposite the po­lice box.

Yoshinori Kobayashi, D.D.S., Ph.D., Nippon Dental Uni­versity, 2-3-16 Fujimi, Chiyoda-ku, Tokyo 102. Phone 261-5511.