Temporomandibular Disorders Lecture note on Oral Medicine

TMJ Disorders

Temporomandibular joint and muscle disorders, commonly called “TMJ” or TMD are a group of conditions that cause pain and dysfunction in the jaw joint and the muscles that control jaw movement.

For most people, pain in the area of the jaw joint or muscles does not signal a serious problem. Generally, discomfort from these conditions is occasional and temporary, often occurring in cycles. The pain eventually goes away with little or no treatment. Some people, however, develop significant, long­term symptoms.

What are the signs and symptoms?

• Radiating pain in the face, jaw or neck
• Jaw muscle stiffness 
• Limited movement or locking of the jaw
• Painful clicking, popping or grating in the jaw joint when opening or closing the mouth 
• A change in the way the upper and lower teeth fit together.

What is the Temporomandibular Joint? 

 

The temporomandibular joint connects the lower jaw (the mandible) with its condyle, to the bone at the side of the head—the temporal bone. If you place your fingers just in front of your ears and open your mouth, you can feel the joints.

Because these joints are flexible, the jaw can move smoothly up and down and side to side, enabling us to talk, chew and yawn. Muscles attached to and surrounding the jaw joint control its position and movement.

To keep this motion smooth, a soft disc lies between the mandibular condyle and the temporal bone.

This disc absorbs shocks to the jaw joint from chewing and other movements.

What are TMJ Disorders?

TMJ disorders fall into three main categories:  

• Myofascial pain, the most common temporo- mandibular disorder, involves dis­comfort or pain in the muscles that control jaw function.

•  Internal derangement of the joint involves a displaced disc, dislocated jaw, or injury to the condyle.

•  Arthritis refers to a group of degenerative or inflammatory joint disorders that can affect the temporomandibular joint

A person may have one or more of these conditions at the same time. Some people have other health problems that co­exist with TMJ disorders, such as chronic fatigue syndrome, sleep disturbances or fibromyal­gia, a painful condition that affects muscles and other soft tissues throughout the body.

How jaw joint and muscle disorders progress is not clear. Symptoms worsen and ease over time, but what causes these changes is not known.

Most people have relatively mild forms of the disorder. Their symptoms improve significantly, or disappear spontaneously, within weeks or months.

For others, the condition causes long­term, persistent and debilitating pain. The condition is more common in women than in men.

Prosthodontic treatment, in order to stabilize the occlusion as a result of a TMD articular diagnosis such as localized osteoarthritis or degenerative joint disease (DJD), may be required once the condition has been successfully stabilized. 

The degenerative process creates a smaller condyle which often alters the jaw posture causing an uneven bite.  Thus, it may become necessary to re-establish a more stable occlusion as a result of changes within the joint.

Trauma to the jaw or temporomandibular joint plays a role in some TMJ disorders. But for most jaw joint and muscle problems, scientists and clinicians don’t know the causes.

There is no scientific evidence that clicking sounds in the jaw joint lead to serious prob­lems. Jaw noises alone, without pain or limited jaw movement, do not indicate a TMJ disorder and do not always indicate that treatment is needed.

What causes TMJ Disorders?

The roles of stress and tooth grinding as major causes of TMJ disorders are also unclear. Many people with these disorders do not grind their teeth, and many long­time tooth grinders do not have painful joint symptoms.

Scientists and clinicians note that people with sore, tender chewing muscles are less likely than others to grind their teeth because it causes pain.

Stress may play a role in many persons with jaw joint and muscle disorders that is more likely the result of dealing with chronic jaw pain or dysfunction than the cause of the condition.

How are TMJ Disorders Treated?

Because more studies are needed on the safety and effectiveness of most treatments for jaw joint and muscle disorders, experts recommend using the most conser­vative and reversible treatments when possible.

Reversible treatments do not cause permanent changes in the structure or posi­tion of the jaw or teeth. Even when TMJ dis­orders have become persistent, most patients still do not need aggressive types of treatment.

Treatment by a Prosthodontist may be needed for other reasons such as to restore severely worn, damaged, or diseased teeth or to replace teeth for the purpose of improving chewing, providing enhanced support for your lips or cheeks, or improving the appearance of your smile.

Extensive prosthodontic treatment should only be provided after the TMJ disorder has been adequately diagnosed and its pain successfully managed.

Conservative Treatments

Most jaw joint and muscle problems are temporary and do not get worse. Treatment is based on a proper diagnosis which should be conservative and reversible.

Self-Care Practices

Pain Medications

Stabilization Splints

Prosthodontic Treatment

Self-Care Practices 

Your Prosthodontist may recommend steps that you can take that may be helpful in easing symptoms, such as:

• eating soft foods,
• applying ice packs to recommended areas,
• avoiding extreme jaw movements (such as wide     yawning, loud singing, and gum chewing),
• learning techniques for reducing stress,
• practicing gentle jaw stretching and relax­ing exercises that may help increase jaw movement.

Pain Medications

For many people with TMJ disorders, short­-term use of over-­the-­counter pain medicines or nonsteroidal anti-­inflammatory drugs (NSAIDS), such as ibuprofen, may provide temporary relief from jaw discomfort.

When necessary, your dentist or doctor can prescribe stronger pain or anti­inflammatory medications, muscle relaxants, or anti­depressants to help ease symptoms.

Stabilization Splints

Your Prosthodontist may recommend an oral appliance, also called a stabilization splint or bite guard, which is a plastic guard that fits over the upper or lower teeth. Stabilization splints are the most widely used treatments for TMJ disorders.

If a stabilization splint is recommended, it should be used only for a short time and should not cause permanent changes in the way your teeth bite together when the splint is removed from your mouth.

Prosthodontic Treatment

Occlusal splints may also be used to reestablish the bite prior to prosthodontic treatment.

It is used when the bite is not contacting evenly due to missing or worn teeth and may relax the muscles.