Temporomandibular Joints (TMJ)


The temporomandibular joint (TMJ) connects the lower jaw called the mandible, to the temporal bone at the side of the head. There are two TMJs, one on each side of the jaw and are flexible so that the jaw can move smoothly, allowing us to talk, chew and yawn. Muscles attached to and surrounding the jaw joint controls its position and movement. When we open our mouth, the rounded ends of the lower jaw joint, called condyles, glide along the joint socket of the temporal bone. These condyles slide back into place when we close our mouth. To keep this motion smooth a soft, shock-absorbing disc made of cartilage lies between the condyle and temporal bone. These parts make up the TMJ.

TMJ disorders are a group of medical problems related to the jaw joint. There are three main categories of TMJ disorders; they are muscle disorders, derangement disorders and degenerative disorders. The muscle disorders include pain in the muscles that control jaw function, as well as pain in the muscles of the neck and shoulders. Derangement disorders relate to derangement of the TM joint, such as a dislocated jaw, displaced disk or injured bone. The last, degenerative disorders include wear and tear of the TM joint, often caused by arthritis and this leads to destruction of the cartilage that covers the TM joint.

TMJ disorders may be caused by injuries, deterioration due to aging, and behavioural factors. Symptoms of this disorder include headaches, ear pain, bite problems, clicking sounds and locked jaws. A heavy blow to the jaw could fracture the bones of the joint or damage the disc, disrupting the smooth motion of the jaw and cause pain or locking of the joint. Aging problems, such as arthritis, as well as the regular gum chewing of some people can cause wear and tear of the joint. Teeth grinding and clenching can increase wear on the cartilage of the TM joint, which can lead to ear and jaw pain. Abnormal position or missing teeth (malocclusion) plays an significant role in the deterioration of the joints and often orthodontic treatment or replacement of molar teeth with dental implants of partial dentures are needed to improve the symptoms.

Conservative treatment such as rest, heat and ice treatment, physical therapy and anti-inflammatory medications are the best place to start. In order to rest your jaw, avoid hard or chewy foods or opening your mouth too wide. A splint or bite plate can be used to reduce clenching and grinding, which will ease muscle tension. If none of these treatments seem to help, occlusal appliances can be used to relax muscles, stabilize and protect the joint and relieve the load on the disk. In extreme cases surgical replacement of jaw joints with artificial implants can be done, but this is still a controversial treatment.