Your jaw joint (temporomandibular joint or TMJ) is located where the temporal bone of your skull connects with your mandible (lower jaw). You have one joint on each side of your head.
The temporomandibular joint (TMJ) is a complex structure that can move your lower jaw up and down, forward and backward, and side-to-side. The lower jaw extends upward to a condyle on each side. This allows the jaw to pivot and slide along the base of the skull. Muscles, cartilage, a cushioning disk (meniscus), and fibrous capsules containing fluid help the joints function correctly and smoothly. If any part of the jaw joint is damaged, the joint may no longer function properly. This is known as TMJ dysfunction.
TMJ dysfunctions can affect chewing, biting, and speech. They can also cause pain and headaches. Other symptoms include clicking, snapping, popping, locking, or grating of the jaw. Each symptom represents a different step along a path of successively more serious problems. At each step along the path, there may be various degrees of pain (or no pain at all).
TMJ dysfunctions are skeletomuscular disorders and can be costly to diagnose and treat. For insurance purposes, it is typically considered a medical issue, although some dental plans provide limited coverage.
Not all causes of TMJ dysfunctions are known, but some commonly identified issues arise from:
- Jaw injuries from forceful impacts that cause fractures to the condyle.
- Tears or inflammation in the fibrous joint capsule.
- Chronic damage or erosion to the meniscus, cartilage, or jaw bone.
- Degenerative joint disease in the jaw joint (temporomandibular joint or TMJ), such as osteo arthritis or rheumatoid arthritis.
- Certain medications
- Cancer treatments of the head and neck.
- TMJ disorders are more prevalent in women than men. Research is ongoing to determine if there are genetic or hormonal connections.
- Since the jaw joints are the fulcrum against which chewing muscle forces are exerted, heavy muscle contractions may apply excessive force to the joints, causing damage.
- Grinding or clenching (bruxism) (Bruxism): Grinding or clenching your teeth can injure the joint capsules and/or cause inflammation in the joints.
- Missing teeth: Problems with your jaw joint (temporomandibular joint or TMJ) can occur if you are missing some or all of your back teeth. This can occur because your back teeth help support your jaw joints. If teeth are missing, the jaw joint bears additional force when you bite or chew. Missing teeth may also lead to bite collapse (loss of vertical dimension of occlusion), which can create further problems with your jaw joints, as excess lower jaw rotation compresses the sensitive nerves and blood vessels that supply the joints.
- Tooth wear (attrition): If you have severely worn teeth, your bite may close farther than normal. This can also place additional strain on your jaw and cause problems with the jaw joints.
- Misaligned teeth (malocclusion): Misaligned teeth can cause strain on the jaw joint, contributing to TMJ dysfunction.
- Eating disorders
- Autoimmune diseases like rheumatoid arthritis , and certain connective tissue conditions can affect the jaw joints.
- Sinus pain or earache: Because your sinuses, ears, and jaw joints (temporomandibular joint or TMJ) are all close to the jaw, you may misinterpret jaw joint pain as sinus pain or an earache.
- Pain, fatigue, or soreness in the jaw joint: Generally, pain in the jaw implies the jaw joint has become inflamed, which is common with TMJ disorders. Chewing is a common trigger of jaw pain associated with TMJ disorders.
- Headaches: TMJ disorders may cause headaches. Grinding or clenching (bruxism) may also be the cause of headaches, particularly those that originate in your temples or radiate from your jaw muscles.
- Clicking jaw joint: When the cushioning disk (meniscus) located between the upper and lower jaws has developed an irregularity, the ligaments holding the disk in place may become stressed, stretched, or altered. This can cause the jaw to no longer track smoothly when opening or closing, resulting in clicks or snaps.
- Popping jaw joint: If your jaw 'pops,' it may suggest the meniscus has been damaged or has developed a bulge. The location of the 'pop' can help pinpoint where the bulge has developed. For example:
- When you open your mouth, a 'pop' may suggest that a bulge in the disk has developed in the forward portion of the joint compartment. This bulge can block the lower jaw from sliding forward.
- A 'pop' when closing your mouth may suggest that a bulge in the disk has developed in the back portion of the joint compartment and may be blocking the lower jaw from returning to a normal position.
- A 'pop' that occurs when both opening and closing the mouth may indicate that the disk has bulged both forward and rearward.
- Locking jaw joint: When this occurs, the meniscus may have developed an irregularity, or the ligaments that hold the disk in place may have become stressed, elongated, or otherwise damaged. This may block your jaw from opening or closing properly.
- A grating sound: If you hear a grating sound when opening or closing your mouth, it may be a sign that a hole has worn through the meniscus. As a result, the condyle is rubbing directly on your skull bone. Excessive wear on the bones can produce rough projections that produce grating sounds when they rub against each other. This can lead to a more serious condition known as TMJ arthritis . It can occur in either or both joints.
When you visit your dentist for jaw pain, they will:
- Review your dental and medical history. They will ask you about habits and lifestyle choices that may be contributing to your symptoms.
- Evaluate the motion of your jaw. They will assess if your jaw moves significantly to the left or right, if there is a problem opening your mouth, and if your jaw locks when you open or close your mouth. They will also check to see if your lower jaw opens as wide as normal.
- Examine how your upper teeth and lower teeth line up when your jaw muscles are at rest. Misaligned teeth (malocclusion) may cause greater forces to be placed on the jaw joints (temporomandibular joint or TMJ), which can lead to TMJ disorders.
- Look for signs of heavy muscle activity such as tooth wear (attrition), chipped teeth , cracked teeth , or abfractions at the gum line.
- Assess your pain level. Your dentist will generally place inward and forward pressure on the condyles when your mouth is closed to see if it causes pain. They may place their fingertips into your ear hole. A painful response may indicate an inflammation of the fibrous joint capsule and is often one of the earliest signs of progressing trouble in the joints.
To diagnose a TMJ disorder, your dentist may:
- Touch your jaw, ears, and jaw joints to feel and listen for pops, clicks, or grating.
- Use a stethoscope to listen to the joint as it moves.
- Use an electronic device that measures electrical activity in the muscles.
- Use advanced imaging techniques, such as tomograms , CT scans, Magnetic Resonance Imaging (MRI), and cone beam scans.
- Inject a contrast dye (visible on fluoroscopic X-ray (radiograph) images) into the jaw joint to check for perforations in the cushioning disk. This is called an arthrogram and is likely to be prescribed if you have locking of the jaw joint (open or closed), severe popping, grating, or significant pain.
Jaw pain is often temporary and does not require diagnosis or additional services. If you are experiencing ongoing pain, you should consult your dentist for further evaluation. They will likely first recommend at-home remedies or less invasive dental treatment. Potential treatment options include:
- At home remedies: These include over-the-counter pain relievers, ice packs, and jaw stretching exercises. Your dentist may recommend that you avoid chewing gum. They may also suggest you avoid yawning, yelling, cheering, or singing loudly, as these actions will cause you to strain your jaw muscles.
- Assisted therapies: Acupuncture, massage therapy, or chiropractic treatment can be effective in relieving jaw pain. These treatments may also be effective at minimizing bite stress from grinding or clenching (bruxism) that can cause jaw pain.
- Occlusal guards : Your dentist may recommend an occlusal guard if your symptoms are chronic . Occlusal guards can help produce a more even distribution of force on your teeth and jaw joints (temporomandibular joint or TMJ) and relieve stress on your jaw muscles.
- Repositioning appliances : There are a variety of non-invasive appliances that may treat TMJ disorder symptoms. It's important to follow your dentist's specific instructions when using these appliances as failure to do so can cause additional pain and damage.
- Occlusal adjustment : Your dentist may recommend adjusting the way your teeth fit together when you bite so that biting forces are distributed more evenly among the teeth. The overall process of achieving the equal distribution of bite forces is called occlusal equilibration (Occlusal equilibration).
- Orthodontic treatment : Your dentist may recommend orthodontic treatment if misaligned teeth (malocclusion) are suspected as a primary contributing factor to your TMJ disorder.
- Replacing teeth: Replacing missing teeth may be recommended if your dentist suspects this is the primary cause of your TMJ disorder. Options may include dentures, bridges (fixed partial denture), dental implants , or combinations of these treatments.
- Jaw surgery: Severe TMJ disorders may require surgery.