“TMJ”…What is it?

TMJ temporomandibular joint

Everybody has TMJ — in fact everybody has two of them! The TemporoMandibular Joint is the connection point for the jaw to articulate (connect) with the stable upper arch. It's a complex joint and is able to move in several directions when functioning, which is important for proper chewing and other movements.

The joint becomes dysfunctional when it's abused or overloaded and becomes unstable. Clicking or popping sounds may occur, or facial pain in the form of headaches or neck pains that appear frequently are also a common complaint.

The true disorder is called TMD-TemporoMandibular (joint) Dysfunction.

Frequently the joints may feel painful because some surrounding structures could be the primary source of the pain. When the joint becomes painful, many times it occurs because of excessive loading or displacement when chewing, or other activities such as clenching and bruxism, or tooth grinding.

A healthy joint is very capable of adjusting to heavy or frequent loading to a point, but if its threshold of tolerance is exceeded, many other conditions can appear and they show up in various ways. Earaches, dizziness, grating sounds when chewing, clicking or popping or an inability to open wide, as well as restricted movements side to side are commonly reported. Tooth fracturing is also frequently seen.

There are many joint disorders that can occur, but the primary cause for many of the cases is the joint being overloaded or abused due to the forces that have been placed on them.

One of most frequently used treatments that have been employed is the use of carefully designed hard acrylic splints, or nightguards, that are worn at night to separate the two arches and prevent further wear or fracturing of the teeth. This treatment can be very helpful when properly designed and used as recommended.

Have you ever gone to a restaurant and sat down at a table, placed your hands on it only to have it wobble annoyingly? There are four legs and they should all contact the floor at the same time. You call your waitperson over and a wedge or book of matches is produced to shore up the shorter leg so the table becomes balanced.

A well designed acrylic splint serves the same purpose but it must be stabilizing in its design so that the joints are seated in the proper position when the splint contacts the teeth on both sides. This takes time to develop when the appliance is inserted into a patient’s mouth and it is correspondingly adjusted to a predetermined alignment of the two dental arches. This requires precise adjusting of the appliance and may require several appointments in some cases due to the continual changes in the affected joint(s) as the healing progresses.

A lack of proper adjusting or failure to establish a stable joint position can create a larger problem that can destabilize the joint further.

An improper bite alignment of the natural dentition can create the same condition which may have contributed to the problem initially.

How often do we contact our teeth in normal function? Countless numbers have been suggested, but studies have shown that in normal function our teeth contact each other only about 20 minutes a day and that is when we swallow.

In the act of chewing with normal force, our teeth rarely contact each other because we have food between them. The majority of tooth contacting is made only when we initiate the act of bruxing or grinding our teeth back and forth.

Clenching our teeth together is a frequent activity for many people. The load that is placed on your teeth, bony structures, muscles and joints can be as high as 10-20 times the force that we place on our teeth when we are chewing normally. It is widely recognized that this occurs much more frequently at night than during the day when we can more consciously control it.

Wearing a well-designed appliance at night can, many times, interrupt this habit, but it is critical to have the joints in a stable position for this to be effective. Quick-fix or over-the-counter nightguards should be avoided because of the potential for further instability.

Dr. Peter Nissler practices in Encino, CA. He has held faculty positions at 4 different dental schools and has lectured and taught hands-on courses on this subject, both nationally and internationally, since 1976. Visit his website at: www.petercnisslerdds.com.

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