The jaw joints are also known as the temporomandibular joints (TMJ). They connect with your jaw muscles, ligaments, tendons, bones and teeth. All are important for normal mouth opening, eating and talking.
Problems that affect jaw joints and muscles, called temporomandibular disorders (TMD), can have a variety of causes. Even simple activities, which most of us do not think about, can create jaw discomfort. These are not a part of normal jaw movement during the day, and include tooth clenching, fingernail biting and gum chewing. Clenching or grinding the teeth, wear due to aging, or a bad bite when the teeth do not align well can all cause TMD. More serious TMD symptoms can develop after motor vehicle collisions and sports injuries.
TMD symptoms are common. For most people, symptoms are brief and will resolve without treatment. About five to 10 per cent of people see a physician because of an ongoing jaw problem. In most cases, conservative and reversible treatment is all that is needed. Women between puberty and menopause are most likely to see a physician for jaw problems that are not due to injury. Men’s jaw problems are usually the result of a motor vehicle collision or a direct injury. Research is not clear on why women are more at risk for jaw problems. Some health problems do occur more in men and others in women. For instance, migraine headaches are not common in men but are for teen and adult women.
To form the jaw joint, the lower jaw (mandible) connects to a part of the skull (the temporal bone) in front of the ears. The connecting part of the lower jaw is called the mandibular condyle. Between the condyle and the skull is a cushion that acts as a shock absorber. It is called the articular disc. The disc and a special type of fluid (synovial fluid) work together so the jaw moves smoothly.
Problems with the TMJ are noticed when the articular disc moves off of the top of the condyle, which is its normal position. This is called disc displacement. Clicking, cracking or popping noises will be heard when the jaw is opened and moved from side to side. The noise is heard next to the ear, but is not a problem within the ears. The ear and TMJ are not connected, just close to each other. Jaw joint noises with no pain and normal mouth opening do not require treatment.
Sometimes the articular disc moves so far out of position that the mouth cannot be opened more than the width of one or two fingers. This is called a closed lock. If it lasts more than a day or two, it is necessary to involve a dentist, a physiotherapist or a chiropractor. The goal is to start gently increasing jaw movement. If there is pain, anti-inflammatory medication from the local pharmacy or a prescription medication from a dentist or doctor may be needed.
Sometimes the mouth can become stuck open. This is not disc displacement – it is because the jaw joints are double jointed and the condyles have gone out of their socket! Some people will go to hospital emergency to get their jaw back in place. Others go to a dentist who knows about jaw disorders. Fortunately, these open locking episodes are very rare.
Inflammation problems can affect the jaw joints, and can be quite painful. They are due to trauma, degenerative (breaking down) changes like arthritis, autoimmune disorders, and infection. Very rarely, they can be from cancer. The most common inflammation, called capsulitis, can be felt by pressing over the jaw joint. Retrodiscitis is the name for inflammation inside the jaw joint. The pain comes from tissues inside and from the posterior part of the jaw joints.
Degenerative joint disease can involve both capsulitis and retrodiscitis. Degenerative changes are often associated with grinding. Grating sounds, called crepitation, are the result of a bone-on-bone contact within the jaw joint. Autoimmune conditions that affect jaw joints include rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis.
Inflammation within the jaw joints can change the way teeth fit together. However, changes that may affect the way your teeth come together should be addressed only once the inflammation, pain and jaw bone structures have become stable. This should be verified by special TMJ computerized tomography (CT – a type of x-ray) and bone scanning.
Jaw fatigue, tightness, and achiness are common jaw muscle symptoms. They may be constant or only felt when the jaw is moved. Such symptoms can make it difficult to open the mouth. Common muscle disorders can also affect the jaw. Jaw myofascial pain is pain that comes from muscle and surrounding tissue. The pain may radiate to other locations, including the teeth and ears. It can create headaches. Another condition, jaw muscle spasm, can come from trauma or from gum infection due to partially erupted wisdom teeth. Persistent jaw muscle pain is similar to fibromyalgia. It is created by abnormal pain messages sent from the central nervous system.
Different strategies can be used to treat jaw disorders. Medication, oral appliances, physiotherapy and massage are all possibilities. Surgery may be used for more severe cases but is rarely required.
Medications that may be used for jaw disorders may include:
If medication is required, be sure to follow up regularly with your prescribing dentist, doctor and pharmacist.
Oral appliances, called occlusal splints, are effective and routinely used for managing TMD. These appliances should be made with a hard acrylic, be removable, and cover either the upper or lower teeth. The appliances are designed to prevent tooth wear, reduce tooth mobility, can reduce nighttime clenching, grinding, and tooth tapping intensity and frequency, reduce jaw muscle pain, and maintain TMJ bone stability.
All oral appliances should be checked from time to time, and adjusted by an experienced dentist. It is possible for the bite to change if splints are not used properly. Complications can develop if oral appliances are used incorrectly or too often. They include dental decay, inflammation, mouth odors, speech difficulties, tooth movement, and psychological dependence.
Physiotherapy and massage therapies are effective and conservative treatments for problems with the muscles and skeleton, including TMD. Physical therapy helps to find and reduce such problems. It can improve joint range of motion and increase muscle function.
The majority of people with jaw joint difficulties will never require surgery. Mother Nature has provided the joint with self-healing abilities. Conservative care is needed by dentists or doctors who understand the diseases and injuries involved. If surgery is required, an effective approach is arthrocentesis. It involves first anesthetizing (‘freezing’) the joint. The joint is then flushed with a sterile saline (salt) solution, followed by cortisone. Afterward, a physiotherapist will help to improve jaw movement.
If you have a jaw joint or jaw muscle disorder, never consider having your teeth adjusted as a first treatment. This includes having your teeth ground down (occlusal adjustment or equilibration), orthodontic treatment (braces), restorative dentistry (inlays, onlays, crowns or bridges), and jaw surgery. There is no scientific evidence to support these extensive and expensive treatments, which are also not reversible. As well, there is no scientific support for the use of electromyography (EMG), joint vibration analysis or sonography to diagnose or treat a TMJ disorder.
If you are experiencing jaw problems and think TMD might be an issue for you, talk to your doctor or dentist about possible solutions and referral to a dentist who knows about jaw disorders.