Have you ever heard someone say they suffered from TMJ? While you may know what they were talking about, it’s a common misnomer. TMJ stands for Temporomandibular Joint. When people talk about having jaw pain, they are referring to TMD, or Temporomandibular Joint Dysfunction or Disorder. The terminology isn’t the only confusing thing about this condition. First, let’s see if we can make sense of this complicated joint!
What is the TMJ?
As we said, TMJ refers to the actual joint where the condyle of your mandible (lower jaw) meets the temporal bone of your skull. Put your fingers right in front of your ears and open. Feel that? That’s your TMJ! It’s a fancy name for a ball and socket joint. The thing that makes the TMJ unique is that it is the only joint in your body that is bilateral! Let’s think about that for a minute. You have a TMJ on each side of your head. Working together, this magical joint allows you to perform an array of vital functions such as chewing, swallowing, sucking, and eating.
Think of all the use your jaw joint gets! Every word you speak, every grape you eat, you’ll be using your trusty TMJ. Now that we know how important it is to sustaining life, let’s take a look at all the parts. Aside from the ball and socket portion of the joint, we have to remember that the chewing muscles and the teeth play a crucial role in the TMJ, as well.
Anatomy of a Jaw Joint
In a nutshell, the TMJ is made up of 2 bones, a disc, 4 ligaments, 5 muscles, your teeth and it creates 5 motions:
- Depression or opening
- Elevation or closing
- Lateral deviation – moving side to side
- Protrusion – moving jaw forward
- Retrusion – moving jaw back toward skull
Together, your TMJ is capable of using these motions to create your circular chewing pattern and allow you to do all the marvelous things you do!
The two bones of the TMJ are the condyle of the lower jaw and the glenoid fossa of the skull. The jawbone’s connected to the head. The condyle is like the ball and the glenoid fossa is the socket. Between them is a piece of cartilage called the disc.
Think of all the movements your jaw has to make to eat and to swallow. It rotates open, slides forward and back, side to side, and it closes. Then remember that it has to work jointly with its partner on the other side of your head! Tricky. When you chew, your jaw creates between 50 and 250 pounds per square inch. Chew on that!
To be able to deliver such force, the joint itself takes a great deal of force. For that reason, the ball and socket have precise positions where they can function the best to deliver the force and to receive it. That’s where the ligaments and muscles come in.
The muscles and ligaments help keep the joint in its optimal position and they are responsible for moving the jaw in all its directions. Don’t forget that your jaw doesn’t just chew. It is also responsible for swallowing, speaking, spitting, and sucking. There is a complex team of muscles that work to get each job done. For now, we will concentrate on the muscles of chewing and of swallowing.
Most people don’t realize that the teeth are considered a part of the TMJ complex. Why is that? Well, this is a unique joint for many reasons! The way the teeth fit together can affect the position of the ball in the ball and socket joint and, because the muscles and ligaments are attached to the joint, they are also affected. Each component of the TMJ relies on the other two for healthy function.
How Does the TMJ work?
When the TMJ is healthy, it works as a team. Imagine you put a bite of food in your mouth. Your cheek muscles and tongue move it to one side and your jaw and teeth work to break it down. When you are done chewing, your jaw shifts to another position, working with your tongue and your swallowing muscles take over. During all this motion, your jaw stays happily braced in its socket, stabilized by ligaments and moved by the muscles in three directions to form five distinct motions. Your jaw acts like a fulcrum and your teeth come together with precision and without interference allowing you to chew in comfort.
What is TMD?
TMD describes any disorder of the TMJ causing pain. Like the joint it affects, TMD is complicated! That’s because it includes a wide variety of symptoms, there is no definitive way to diagnose it, and there is no one known cause and treatments work with varying success. It is a painful condition that can affect all facets of life. Malfunction or injury of any one part of the TMJ (teeth, joint, muscle) can cause TMD.
TMD can be grouped by symptoms into three different categories.
- Muscular pain of the face and neck
- Can be caused by improper bite
- Can be caused by clenching/grinding
Internal Derangement of the disc
- Displaced disc – instead of sitting between the ball and socket, it gets displaced, usually in front of the condyle
- Associated with popping of jaw – condyle “pops” over disc as it moves
- Dislocation of jaw
- Injury to condyle
Degenerative Joint Disease
- Arthritis of the jaw joint
- Affects many areas
How Do I Know if I Have TMD?
While there is no test for TMD, there are many signs and symptoms your dentist is trained to recognize. First, do you have pain? TMD can mimic many other conditions. Some symptoms of TMD to look for
- Pain in joint
- Pain in neck, head, shoulders
- Chronic headaches
- Limited opening
- Vision problems
- Mouth locking open
- Painful popping or clicking
- Teeth don’t feel like they meet correctly
- Jaw muscle soreness or stiffness
- Jaw muscles tire easily
- Ear pain
Talk to your dentist if you have any symptoms of TMD. Sometimes it takes a team of doctors to rule out other causes. Your dentist can examine your joint, muscles, and teeth to help you determine if you have TMD. About 90% of your diagnosis will come from an exam of the joint and its components and from the information you give your dentist and doctors about what you have been experiencing.
What Causes TMD?
Stop asking hard questions! The causes for TMD are not yet clear. Although it affects men and women, it affects more women. Contributing factors are thought to be things like
- Injury to the joint
- Obstructive Sleep Apnea
- Bad bite
- Prolonged opening during dental procedures
- Certain hormones
- Habits like excessive gum chewing
You may not have an explanation for why you are suffering from TMD.
Be aware that there are a group of diseases and conditions that often show up alongside TMD. That doesn’t mean that one causes the other, but that while the relationship is not yet known, it happens often enough not to be a coincidence.
- Chronic Fatigue Syndrome
- Interstitial cystitis
- Irritable Bowel Syndrome (IBS)
- Sleep disorders
How Do You Treat TMD?
Because TMD is not yet fully understood, the focus is on conservative and reversible treatments. Many times, TMD symptoms will go away on their own with rest. Some treatments include
Palliative – Make it feel better
Consider first treating TMD like you would a joint or muscle injury.
- Limit opening with yawning
- Soft foods
- Ibuprofen or another anti-inflammatory
- Avoid gum
You can also try some physical therapies at home. Your dentist can show you some gentle stretching techniques like this one:
- Open mouth to a comfortable position, gently place fingers on lower teeth and apply gentle downward pressure, stretching the muscles, then releasing.
Remember that optimal position we talked about? Sometimes interferences in our bite cause the joint to function outside of that position. When this happens, the ball isn’t braced by the socket anymore and the muscles of the TMJ can go into painful spasm. A splint allows your joint to return to its most comfortable position while it is in your mouth, by placing a flat plane of plastic between your teeth. Wearing a splint relaxes your muscles and allows them to come out of spasm.
When considering invasive or non-reversible treatments, make sure that you have exhausted all other possibilities. More and more is being learned about TMD every year.
Think of tooth equilibration like balancing your tires. If your tires are off, they can throw your whole car off balance. Remember that happy position of your jaw? If your teeth interfere with your jaws optimal position, the jaw can become unstable. It loses the bracing effect of the socket. If your bite is the cause of your TMD, this option can be very effective. However, keep in mind that it not reversible. Ask your dentist questions about your bite.
In some cases, botox injections have been shown to relieve pain in people with TMD. It is injected into the chewing muscles and gives immediate relief. However, it is not FDA approved for this use and long term effects are not known. Remember how important the muscles are for stabilizing the joint? Botox directly alters the force the muscles can apply. Botox should only be considered if all other options have been exhausted.
There are several surgeries used to treat TMD. However, there is no one definitive surgery that will work for everyone. Surgery is a last resort in treating TMD. Only in the most severe cases should surgery be considered.
Living with TMD
You are not alone! Around 12% of the US population or 35 million people suffer from TMD. There are resources to help. The TMJ association is a not for profit organization that is a great resource for people with TMD.
Your Dentist and Your Jaw
Your dentist is your best ally when dealing with TMD. Your dentist is familiar with all the structures of your joint and can recognize early signs of dysfunction. The more they know, the more they can help you. If you think you might have TMD call your dentist today!