I recently had a patient who had jaw pain following a 2 hour stint at the dentist with her mouth held open. Research has shown that spending extended periods in this position at the dentist can put an unnatural strain on the jaw muscles, and lead to pain, dysfunction and even malpositioning of the jaw (temporomandibular) joints.

The temporomandibular joint (TMJ) is located on each side of the head and allows the jaw to move up and down, side to side, and forward and backward. Problems with these joints can cause pain and discomfort in the jaw, as well as clicking, popping, or grinding sounds when you open and close your mouth.

As the diagram below shows, the TMJ is quite a complicated joint, meaning that there are a number of structures that can potentially get disrupted. Firstly, it’s what’s known as a synovial joint, which means it is surrounded by a capsule and filled with fluid. It also has a number of muscles and ligaments acting across it, and has a small disc made of cartilage sitting as a shock-absorber between the joint surfaces. Problems with this disc can sometimes be responsible for the ‘clicks’ experienced when moving the jaw. It’s even possible to get arthritis in the TMJ.

When the mouth is held open for an extended period of time, such as during dental work, the temporomandibular joint (TMJ) can become stressed in several ways.

Firstly, holding the mouth open for a prolonged period can cause fatigue and strain in the muscles of the jaw, including the muscles that control the TMJ. This strain can lead to muscle spasms, pain, and inflammation.

Secondly, holding the mouth open for an extended period can cause the TMJ to become misaligned. The TMJ is a complex joint that allows for a wide range of movement, including sliding and rotating. When the mouth is held open for too long, the joint may become stuck in an open position or may shift out of alignment. This can cause pain, clicking or popping sounds, and difficulty opening or closing the mouth.

Thirdly, holding the mouth open for an extended period can cause compression of the tissues in the TMJ, including the cartilage and synovial fluid that help cushion and lubricate the joint. This compression can cause damage to the joint and lead to chronic pain and dysfunction.

Overall, holding the mouth open for an extended period can put significant stress on the TMJ and its surrounding tissues.

Can Osteopathy help with TMJ problems?

There is research showing that gentle stretching of the joints and massage of the muscles acting across the jaw can help to alleviate TMJ problems. Treatment of the neck can also assist with TMJ problems, and there is even a specific osteopathic manipulation for releasing the TMJ itself.

One muscle in particular, masseter, the main biting muscle of the jaw, appears to be amenable to massage therapy, including self-massage. You can find this muscle on yourself by (gently) gritting your teeth whilst feeling the sides of your jaw. Masseter contracts when you bite down, and stretches when you open your mouth. As you have one masseter muscle on each side of the jaw, if one is tighter than the other, your jaw will open and close in an uneven way, wiggling slightly.

How do you know if your jaw muscles are too tight?

I was taught that you should be able to open your mouth enough to fit 3 fingers between your teeth. Anything less than this, then you may have overly tight jaw muscles.