Temporomandibular disorders can cause symptoms that are similar to other diseases.

Do you notice clicking or popping when you open your mouth? Is it difficult or painful to open your mouth? Does your jaw occasionally lock, so it is stuck open or closed? If so, you should see your dentist for a consultation and examination. You may have a temporomandibular disorder (TMD). These disorders include problems of the chewing muscles, the jaw joint (called the temporomandibular joint or TMJ), or both.

Here are some key symptoms linked to TMD.

Unusual sounds — Clicking, grinding or popping sounds when you open your mouth are common in people with TMD. The sounds may or may not be accompanied by pain. According to the National Institute of Dental and Craniofacial Research, researchers believe that most people with popping or clicking in the jaw joint probably have a displaced disc. However, they also note that as long as the displaced disc causes no pain or problems with jaw movement, no treatment is needed.

Locking or limited movement — The jaw joint is similar to a ball-and-socket joint except that the socket itself is movable. The jaw joint sometimes may lock in an open or closed position. You may have difficulty opening your mouth either because the joint is locked or because of pain.

" Ear" pain — You may think you have an ear infection, but ear pain may be related to jaw joint inflammation or muscle tenderness. Pain from TMD is usually felt in front of or below the ear.

Headaches — People with TMD often report headaches. Your dentist can help to determine if your specific headache symptoms are a result of TMD. In some situations, you may need to consult a physician to help diagnose and treat certain headaches not related to TMD.

Morning stiffness or soreness — If your jaw muscles are stiff and sore when you wake up, it may by a sign that you are clenching or grinding your teeth in your sleep. Clenching or grinding teeth can exhaust jaw muscles and lead to pain.

Difficulty chewing — You may have difficulty chewing as a result of a change in your bite—the way your upper and lower teeth fit together. This shift in your bite may be related to TMD.

Previous injuries and related conditions — A recent injury to the jaw joint or one from many years past can lead to TMD symptoms. Arthritis in the joint also may arise from injury. Arthritis already affecting other joints may affect the jaw joint and lead to TMD.

Others — Though the research is controversial, a feeling of fullness of the ears or ringing in the ears may sometimes be related to TMD. In these cases, consultation with an "ear, nose and throat" physician can help establish the final diagnosis.

"If these symptoms sound familiar, talk to your dentist. Your dentist will test your ability to open and close your jaw, examine other jaw movements, and feel the jaw joint and muscles for pain or tenderness. The dentist will listen with a stethoscope in front of the ear for any clicking, popping or grinding sounds and will feel the jaw joint while you open and close it.

X-rays are often taken to look at the jaw joint and to rule out other diseases. In some cases, a computed tomography (CT) scan may be needed to further examine the bony detail of the joint. In addition, magnetic resonance imaging (MRI) is sometimes recommended to analyze the soft tissues.

While it is advisable to discuss any TMD symptoms with your dentist, occasional discomfort in the jaw joint and chewing muscles is quite common and usually not a cause for concern. However, if you are diagnosed with TMD, the good news is that simple self-care practices are highly effective in relieving the discomfort. These include eating soft foods, applying heat or ice packs and avoiding extreme jaw movements. Effective, conservative treatments include nonsteroidal anti-inflammatory drugs, muscle relaxants, physical therapy and oral appliances.