TMJ

WHAT ARE TMJ and TMD’s?

Temporomandibular disorders are often called “TMJ” by doctors, sufferers and even insurance agencies; even though the term TMJ is actually an acronym referring only to the jaw joints themselves.

For the purpose of this article, we will go over the basics of TMJ, and then in future discussions, I will bring you more in depth information into each of the areas we touch on today.

Temporomandibular Joints
TMJs are located on both sides of the face approximately one centimeter in front of the ears, connecting the jaw (mandible) to the skull (temporal bone). They are the most intricate joints in the entire human body, providing revolution (pivoting) movement like all joints, as well as descending movement, called translation. That is what allows us to open our mouths wide and move our jaws from left to right. Between the top end of the jaw (condyle) and the socket in the skull is a disc of cartilage, which — like the discs in the neck and back — serve as shock absorbers, protecting the bones from hitting each other. This is the ball and socket joint, the only joint in the head, and if something goes wrong with either one of them, you may begin to experience serious discomfort or even life altering pain.

As mentioned, the TMJ is characteristic of the type of joint called a “ball and socket”. The ball is the rounded part technically known as the “condyle” of the joint. The condyle rotates in a cuplike depression (the socket) technically known as the “fossa.” Although the joint looks like it is attached immediately to the sinuses, it is actually separated from them by soft tissue ligaments, which completely enclose the joint, but are not visible even on an x-ray. Also not visible on an x-ray is the meniscus which is a disk of cartilage, which surrounds the space between the condyle and the fossa and is able to move forward and backward as the jaw opens and closes. The condyle and the fossa are each covered with a thin layer of inflexible cartilage of their own. All three layers of cartilage help to provide smooth, frictionless surfaces for easy joint function.

The Joints Work With the Neuromuscular System
The movement of the jaw is orchestrated by a multifaceted set of muscles, which are, in turn, controlled by the body’s local and central nervous system. Together, they are called the neuromuscular system. The whole jaw-joint system is held together by ligaments, which place perimeters on their range of motion in all directions — just as they do in all the joints of the body.

A Distinctive System of Many Parts
The TMJ joint system is unique in many ways. The left and right joints must coordinate, working at the same time for the jaw to move. While the opening, lateral and forward movements of the jaw are controlled by the shape of the bones and are a function of muscles and ligaments, the closing end-point of the jaw movement is controlled by the coming together of the teeth — the bite or occlusion. No other joint in the body has such a rigid end-point limit.

When a dentist thinks of TMJ, he or she usually considers the issue at large more than just the anatomy of the joint itself. The joint is really a part of the total complex system that makes the jaws operate correctly. To a dentist, the appropriate, vigorous function of the TMJ system requires normal structure and utility of all the component parts, including muscles, nervous system, ligaments, joints, bones, discs, connecting tissues and the dental occlusion. In fact, it is usually pain in these structures that compels most people toward TMJ treatment.

Through modern dentistry, there are several different terms used to describe the problems associated with TMD (defined as a group of symptoms which have a common source). Each term commonly corresponds to a particular “era” in the history of the study of the disorder, but all are still in general use and mean basically the same thing with weight on slightly different characteristics of the syndrome. They include MPD (MyoFascial Pain dysfunction), MFPDS (MyoFascial Pain dysfunction Syndrome), the more general TMD (TemperoMandibular Dysfunction) and the latest in a long line, Craniomandibular Disorders (CMD).

For the purposes of this article, I will use the term TMD to differentiate the painful symptoms of the disease from “TMJ”, the name for the actual joint itself.

Some Symptoms of TMD (an overview)
The symptoms of TMD can include the following:

• Severe headaches
• Neck aches, especially stiff necks
• Ear aches, (which are actually pain in front of the ear or ears)
• Jaw aching on one or both sides
• Extreme difficulty keeping mouth open at dentist’s office
• Joint pain when opening the mouth
• Difficulty opening the jaws wide, especially for any length of time
• An inability to open the mouth at all at times
• Pain when chewing
• Discomfort or pain to any of these areas
• Pain in cheek muscles
• Uncontrollable tongue movements
• Tongue Pain
• Non-specific jaw and jaw joint problems
• Difficulty opening the jaw smoothly or evenly
• Jaw deviates to one side when opening
• Inability to find the correct bite with teeth
• Uncontrollable jaw movements
• Extremely sensitive teeth
• Phantom tooth pain
• Dislocating of jaw, easy and often
• Clenching teeth
• Grinding the teeth, known as bruxism
• Involuntary clicking or popping noises upon opening or closing the mouth
• An extraordinary amount of complications from routine dental procedures
• Dizziness
• Fullness of the ear
• Ringing in the ear
• Ear pain without infection
• Bloodshot eyes
• Blurring of vision
• Eye pain above, below and behind the eyes
• Pressure behind the eyes
• Sensitivity to light
• Watering of the eyes
• Hair and/or scalp painful or very sensitive to the touch
• Sleep apnea

All of these TMD symptoms can vary in seriousness from mild to debilitating. On the mild end, the sufferer may attempt to ignore the discomfort, perhaps not even seeking any relief at all. Escalating on the pain scale a bit, the person may still not fully realize they even need to see a qualified professional, and attempt to get by with over the counter pain relief. At some point, however, sleep disruption, or a variety of other painful, or quality of life issues will begin to crop into the sufferer’s life to the degree where they must pursue professional advice and assistance.

In future articles I will delve into how each of these different symptoms, many of them so seemingly unrelated, can all be so blessedly relieved by a qualified dentist, if indeed it is determined that your troubles are caused by your TMJs.

Pre-Disposing Factors
In this article, we will look a just a few of the many pre-disposing factors which can make you a candidate for TMD.

Differences Between the Sexes
TMD affects women significantly more than it does men. This is somewhat due to the disparity in bone and muscle densities between the two sexes, and partly to differences in psychological outlook and sensitivities to worldviews, et.. Studies show that women are more responsive to emotional imagery and have a stronger cardiovascular reaction to stress than men have.

Age as a Factor
The good news is, that almost universally speaking, TMD follows what can be looked at as a “Bell Curve.” The greatest preponderance of sufferers will experience their worst symptoms between the ages of 25 to 45. This implies that it is related to psychological and physiological variables, which alter throughout life. As the patient ages past the significant age of 45, these variables begin to diminish in such a way that the problem lessens and sooner or later vanishes, sometimes without any treatment at all. TMD does occur in some younger or older patients, of course, but with decreasing frequency as age decreases or increases from the medium age of 35.

Posture
In an ordinary relaxed state, the lower jaw, affected by gravity, tends to drop into eccentric positions away from the regular position in which the upper and lower teeth would normally come together. This is especially true in persons who tend to hold their heads so that their jaw line is not parallel to the floor (perpendicular to the force of gravity). Normally, this would not cause any problems, however persons who grind or clench their teeth may grind in these abnormal positions. This places unequal and eccentric pressures on their face, head and neck muscles as well as the TM Joints. Consider the front desk receptionist who keeps her computer monitor to her left, her keyboard in the pullout drawer under the desk in front of her, and who talks on the phone keeping the receiver tucked between her right shoulder and her right ear. Imagine the strain she is placing on her TMJs, not to mention neck muscles, et.

Occlusion
Occlusion describes the way your upper and lower teeth come together.
In most people, the upper and lower teeth naturally line up so that when they come together, the TM Joints are sitting normally in their sockets. Whenever something disturbs the way they come together, say a new filling or a lost tooth, this can effect the relative positions of the two TM Joints. Grinding or clenching in these eccentric positions can cause muscle splinting (cramping) and joint problems. There is a complex, dynamic balance between the way that the teeth come together, the muscles that work the jaws, the TM Joints, and their relationship to the posture of the head and neck. A change in any part of the system affects all others and changes the balance.

In Conclusion
As you have learned from this introductory article, TMJs, and the troublesome TMDs, describes a group of diseases that can involve the jaw joints, the muscles that control jaw movement and the dental occlusion. TMJ / TMDs are physical disorders arising from an imbalance in the precise working relationship of the jaw and skull with the muscles that move the jaw, as well as the nervous system associated with these systems. This disproportion results in muscle exhaustion, spasm and/or joint dysfunction, and even changes in the teeth, which in turn cause a diversity of symptoms, exclusive to each person. In following articles, we will look further into each area we broached today, and into others, as well.