mouth and dental disorders
Temporomandibular Disorders (TMDs)
Causes of Temporomandibular Disorders
Most often, the cause of a temporomandibular disorder (TMD) is a combination of muscle tension and anatomic problems within the joints. Sometimes there is a psychologic component as well as other factors. Clenching and grinding of the teeth ( Teeth Grinding ), bodywide disorders (such as osteopenia, autoimmune disorders, connective tissue disorders, or genetic bone disorders), infections, injury, Muscle fatigue and overuse, leading to temporomandibular myofascial pain syndrome Internal temporomandibular joint (TMJ) derangement Arthritis Ankylosis Hypermobility Temporomandibular myofascial pain syndrome is the most common disorder affecting the temporomandibular region. Muscle pain and tightness around the jaw and limited mouth opening occur, as well as headache and pain in other areas of the head and neck. Pain is caused mainly by muscle fatigue or overuse, sometimes resulting from clenching or Teeth Grinding while awake or asleep due to psychologic or sleep-related stress. Clenching and grinding while asleep exert far more force than clenching and grinding while awake. Pain can also be brought on by injury to the head or neck, In the most common form of internal TMJ derangement, the disk inside the joint lies in front of (anterior to) its normal position. The disk can be moved out of place when the ligaments that hold it in place become elongated or, often, stretched due to injury to the joint (sprained ligament). Internal TMJ derangement can occur with or without reduction. Reduction means the parts of a joint have returned to their normal positions. Disk displacement with reduction is more common than displacement without reduction and occurs in about one third of the adult population. In derangement with reduction, the disk lies in front of its normal position only when the mouth is closed. As the mouth opens and the jaw slides forward, the disk slips back into its normal position, often making a popping or clicking sound. As the mouth closes, the disk slips forward again. In internal TMJ derangement without reduction, the disk never slips back into its normal position, and the degree to which the mouth can be opened is limited. TMJ derangement can cause inflammation around the joint (capsulitis). Internal TMJ derangements may or may not be painful. Arthritis in a temporomandibular joint may result from osteoarthritis, rheumatoid arthritis, infectious arthritis, or injury, particularly injury that causes bleeding into the joint. Such injuries are fairly common among children who are struck directly on the chin or on the side of the chin. Osteoarthritis (OA) None Rheumatoid Arthritis (RA) None Infectious Arthritis None Traumatic arthritis, which is arthritis caused by an injury (such as when the jaw is stretched widely during a difficult tooth extraction), is rare. Ankylosis is loss of joint movement resulting from a fibrosing (scarring) or fusion of bones within the joint or from calcification (the deposit of calcium into body tissues) of the ligaments around it. Ankylosis most often results from an injury or an infection, but it may be apparent at birth or a result of rheumatoid arthritis. Hypermobility (looseness of the jaw) results when the ligaments that hold the joint together become excessively elongated, like being double-jointed. In hypermobility, dislocation is usually caused by the shape of the joints, ligament looseness (laxity), and muscle tension. It may be caused by trying to open the mouth too wide or by being struck on the jaw. 