The temporomandibular joint or TMJis the joint that opens and closes your mouth. The TMJ connects the mandible or lower jaw to the temporal bones of the skull—the bones on the side of the skull. There are two TMJ joints—one on the left side of the jaw and one on the right. Muscles attached to and surrounding the joint control the movement of the jaw allowing us to talk chew yawn and perform other functions with our mouths. When you open your mouth the condyles the rounded ends of the lower jaw glide along the joint socket of the temporal bone. When you close your mouth the condyles glide back. A soft disc between the condyles and the temporal bone ensures that the opening-and-closing movements are smooth. This disc is made of cartilage that absorbs shocks to the TMJ from chewing and other functions. Many people experience TMJ disease which causes facial pain; jaw clicking popping and locking; earaches; headaches; bite problems; and other unpleasant symptoms. TMJ problems can be classified into three main groups of disorders:· Muscle disorders· Joint derangement disorders· Degenerative joint disorders Muscle disorders affect the muscles that control the TMJ as well as muscles in the face and neck. The patient experiences pain in all or some of these areas. These disorders called mysofacial disorders are the most common of the TMJ disorders. Derangement disorders are caused by dislocated jaw displaced disk and injured bone. Degenerative disorders stem from the wear and tear of the joint and are caused by arthritis and other similar conditions that destroy the cartilage covering the joint. TMJ disorders can be caused by injury aging and behaviour.. Behaviour can include frequent gum chewing teeth grinding teeth clenching. Behvaviours induced by bite problems can also induce TMJ disorders. For example a bad bite might cause a person to chew more with one side of the mouth than the other. Common symptoms of TMJ disorders include:· Pain in the jaw face neck or shoulders· Popping/clicking in the jaw joint· Limited jaw movement· A sudden change in the bite (the way the top and bottom teeth fit together)· Headaches· Earaches· Dizziness· Hearing problemsNote though that one of these symptoms alone does not indicate the presence of a TMJ disorder. One or more of the symptoms above combined with prolonged pain should inspire a trip to the doctor. In order to make a diagnosis of TMJ disorder the doctor will feel the jaw muscles and ask if there is any pain or tenderness. He or she will also check jaw movement and listen for clicking or popping sounds. Finally he or she will evaluate the patient's medical and dental history. Specialized X-ray techniques such as MRI tomography and arthrography can confirm a TMJ disorder diagnosis. Treatment includes jaw rest heat or ice applications and anti-inflammaratory medication. It is important that the patient avoid chewing gum eating hard-to-chew foods and opening the mouth wide. The doctor might also recommend physiotherapy with muscle stretching and relaxing excercises. The patient might also wear a dental splint a plastic device fit over the top or bottom teeth to reduce grinding and clenching. In cases involving abnormal bites it may be necessary to fix the bite in order to treat the TMJ disorder. Extreme cases may require surgery such as tightening the TMJ joint ligament restructuring the TMJ and TMJ replacement.