Temporomandibular joint disease

Temporomandibular joint diseases, disorders, or dysfunction, commonly referred to as TMD or TMJD, refer to any pain or dysfunction of the muscles that move the jaw and the joints that connect the jaw to the skull; these joints are the temporomandibular joints. TMD is characterized by pain, most importantly, and often accompanied by restricted movement, and noises, such as clicking, from the joints when they move. TMD can be chronic and uncomfortable, though it is not life-threatening.

TMD is caused by a number of factors, and there is no one manifestation of the disorders and dysfunctions that affect the temporomandibular joint and surrounding muscles. While there are many treatments that may be effective, there is no one preferred treatment; people who suffer from TMD simply need to learn what works best for them. Treatments include, but are not limited to, bite plates and mouth guards, physical and psychological therapies, and over-the-counter or prescription pain medication. It is generally agreed that invasive therapies, like surgery, are not recommended. TMD is among the most common causes of chronic pain in the face and mouth, and it is estimated that about a quarter of the adult population has some degree of TMD.

The symptoms related to TMD are not thought to relate to a specific disease; in fact, diseases of the temporomandibular joint may not cause any symptoms at all. Instead, these disorders are defined by their symptoms and the area they affect. Their common characteristics are pain in the muscles that are used to chew, usually accompanied by restricted movement of the jaw, and popping, grinding, or clicking noises that are produced when the jaw is in motion. Less common symptoms include pain in other parts of the head and neck, including the teeth, hearing loss or ringing in the ears, and dizziness. Some studies suggest that TMD develops as a result of physical trauma, while other research suggests that TMD is a systemic pain syndrome similar to fibromyalgia or chronic headaches.

Although the exact causes of TMD are not known, there are factors that may predispose people to TMD, and there are factors that may trigger it or prolong its symptoms. People with disc disorders and joint diseases like arthritis are often predisposed to TMD. Stress, anxiety, depression, and anger can all trigger TMD, as these emotional conditions tend to encourage grinding of the teeth and clenching of the muscles of the jaw, which can exacerbate the emotions, which then further exacerbates the symptoms. Hormone fluctuations, as well as bruxism, or chronic and excessive grinding and clenching of the teeth, which is also often exacerbated by emotional factors, may also worsen TMD symptoms. Trauma is a possible cause of TMD; this may be physical trauma, like traffic accidents, or it may be repetitive stress trauma, like prolonged singing or playing certain wind or reed instruments. Extensive dental treatments, in which the mouth is open for a long period of time, may trigger TMD symptoms. Even sudden movements, like excessive yawning or aggressive laughter, may lead to TMD symptoms. Historically, researchers have believed that occlusal abnormalities, or problems with the bite, could cause TMD, though this is no longer widely believed. Finally, there may be a genetic predisposition to chronic pain syndromes, including TMD, but this idea lacks sufficient supporting evidence.