What exactly is a TMD?
According to the American Academy of Craniofacial Pain, TMD or Temporomandibular Disorders are a group of maladies which can effect the temporomandibular joints (the jaw joints located immediately in front of your ears), as well as the associated muscles of the jaw, face and neck as well as related neurological and vascular structures.
A great video to understand TMD, its causes, and its consequences is below by Dr. Curtis Westersund:
Where is the Temporomandibular Joint located?
The temporomandibular joint connects the mandible (lower jawbone) to the temporal bone of the skull in front of the ear (Fig.). Within the joint formed by these two bones, there is a tiny disc of cartilage. The masseter and temporal muscles provide power to the joint, making it one of the most used joints in the body. The temporomandibular joint is responsible for all the movements of the jaw, including chewing, swallowing, breathing, and talking.
What contributes to TMD’s?
Muscular related TMD’s involve the improper usage of muscles in the jaw, neck, shoulders and back. The head weighs approximately 10-12 pounds. Imagine your head is a bowling ball balanced on top of a pencil by a number of rubber bands. When muscles are tense, they shorten. Now imagine shortening just one of those rubber bands. Some rubber bands would stretch, some would shorten, and the bowling ball would be thrown off balance. Similarly, when even a single jaw, neck, or shoulder muscle becomes shortened, all of the other muscles are forced to overwork to keep the head balanced on top of the spinal column. We see then that dental headaches originate from an unstable bite which cause the muscles of the jaw, head, and neck to overwork and become painful. Once the muscles become painful, a vicious cycle begins. The pain makes you feel tense and uptight. This worsens the muscle spasm, which in turn increases the pain.
Is a misalignment of the teeth. Orthodontists work to provide a patient with the proper form of the teeth and jaws but that may not be enough.
Training your tongue to rest on the roof of your mouth is absolutely critical in helping to relax your jaw muscles and keep your teeth apart. When someone is a mouth breather, the jaw drops down and back placing extra weight on the joints.
Forward Head Posture
A forward head posture can also set the stage for clenching. As soon as you bring your head forward, your teeth tend to come together. If you clench, you may be able to feel a bite line in your own mouth by sweeping your tongue along the inside of your cheek. If you feel a horizontal line along the inside of your cheek where your teeth come together, there is a good chance you are clenching or grinding. Remember…the head ALWAYS follows the tongue. If the tongue is down and on the floor of the mouth INSTEAD of up in the roof of the mouth, the head naturally follows and is forward. The ear should align over the shoulder, and the shoulder should align with the hip for proper positioning.
Chewing on one side of the mouth
When we chew, our tongue should stay in one spot behind our upper front teeth, with food equally balanced on both sides of our mouth. We should not be chewing on one side (unilaterally), or using our tongue as a shovel to move food around in our mouth. Many people who are tongue thrusters or have a restricted tongue have issues with chewing on both sides. This can be taught through myofunctional therapy.
If your bite is unstable, as from poorly aligned teeth or even a missing tooth, the muscles must work harder to bring the teeth together. Jaw muscles never get a break and the overworked muscles become strained. When muscles are under constant strain, they eventually become painful.
Clenching and Grinding (Bruxism)
Are conditions of the jaw often related to oro-facial muscle weakness. Recent research also shows a strong correlation between bruxism and sleep apnea.
Clenching usually occurs during the day. Most people are completely unaware that they clench. Here is how I explain clenching to my patients. Anytime our teeth come together and touch (other than brief moments of swallowing/chewing) this is considered clenching. Our teeth should NEVER be touching. They should be slightly apart with our lips closed and our tongue spread out across the roof of our mouth. All of our daily habits carry over into our sleep patterns at night.
Grinding (Bruxism) usually occurs in our sleep and often at the end apnea/hypopnea events in both the supine and lateral postures. Research and studies show that obstructive sleep apnea (OSA) was the highest risk factor for tooth grinding during sleep.
Nail Biting and Chewing Gum
The teeth shift out of their normal occlusion, a downward resting posture of the tongue is encouraged, and extra force is placed on the jaw joints. Myofunctional therapy provides specific regimens to help the individual break these detrimental habits.
Hand Leaning against the Face (propped up while reading, watching T.V, at the computer, etc.)
This constant pressure puts extreme stress on the jaw joints and over time can cause the inward push of the teeth. I often see this in my young adult patients. It is crucial to stop these habits early on. Myofunctional therapy works to break these habits and invoke the “one foot rule”.
Some common drugs can actually cause clenching. This side effect is found in antidepressants, which are commonly prescribed to treat depression, anxiety, obsessive-compulsive disorder, and post-traumatic stress disorder. A few examples are Prozac, Zoloft, Lexapro, and Paxil.
Caffeine intake doubles the incidence of grinding.
For a more technical demonstration of the joint, you can watch the animation below:
Myofunctional Therapy and TMD Treatment
Myofunctional therapy can help reduce many of the painful effects of TMD by teaching proper oral and muscular function. Myofunctional Therapy works in conjunction with full mouth reconstructions, orthodontic treatments, jaw surgeries, snoring, and sleep apnea. 90% of TMD’s are muscle related and paying attention to muscle function will go a long way as far as stable dental results are concerned.