What is Temporal Mandibular Joint Disorder or TMJD
December 1, 2015
The temporal mandibular joint (TMJ) is the joint that joins the mandible, or lower jaw, to the temporal bone in the skull. The TMJ is a synovial joint, which means that there is a capsule of connective tissue surrounding the joint. This articulation is unique in that the joint surfaces of the mandible and the temporal bone are both convex. In order to create smooth motion of the two surfaces, a disc between the two bones sits over the condyle on the mandible and helps to guide the motion of this bone over the temporal bone as we open and close our mouths to eat, talk, and chew.
Several ligaments lend stability to the joint and guide motion of the joint and the disc as we open and close our mouths. Multiple muscles control the motion of the jaw and can be a source of pain for many people. Pain or difficulty opening and closing the mouth is called temporal mandibular joint disorder (TMJD). The incidence of this condition is between 5- 12% according to the National Institute of Dental and Craniofacial Research. It occurs more frequently in young people and in women more than men.
Causes of TMJD
TMJD is triggered by muscle irritation, joint immobility, faulty occlusion or bite, and/or displacement of the disc between the joint surfaces. These problems may be caused by poor posture, nail biting, clenching and grinding the teeth. Occasionally patients can experience facial pain following dental work involving prolonged opening of the mouth, or radical orthodontic repositioning of the teeth.
The facial muscles control the smooth movement of the jaw to open and close the mouth. These muscles can be a source of facial pain when they are overworked due to abnormal motions of the jaw or increased activity. In addition, if the disc between the joint surfaces becomes displaced, the motion of the jaw may be altered and painful. Disc displacement can also cause popping in the joint with opening and closing of the mouth.
Symptoms of TMJD
Symptoms of TMJD can include headache, neck pain, clicking or popping at the TMJ with opening or closing of the mouth, decreased range of motion of opening or closing of the mouth, ear pain, and abnormal motion of the jaw. TMJ function can be influenced by the position of the head on the neck resulting in both jaw pain and headaches. When the head sits forward on the cervical spine, increased activation of the muscles in the front of the neck below the jaw pulls the mouth open. Because of this the muscles around the jaw have to work more to keep the mouth closed. There is also increased activation of the muscles in the upper neck to keep to hold the head up against gravity. Increased tone and tension of several neck and facial muscles can cause headaches. Clenching and grinding the teeth can also cause increased tension of the facial muscles.
Treatment of TMJD
Physical therapy treatment of the TMJD includes postural assessment, facial and cervical range of motion assessment, assessment of facial, cervical and thoracic mobility, and strength testing. Based on the findings of the initial evaluation, your physical therapist will work with you to improve the mobility and strength deficits that are found. Research has shown that manual therapy (joint and soft tissue mobilization) to the TMJ, cervical, and thoracic spine, as well as exercises to improve posture and strength of the cervical and thoracic spine helps to decrease pain in the temporomandibular region. A physical therapist may also work with a dental specialist as part of a multi-disciplinary team to address the problem.
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