What is TMJ Disorder?
Temporomandibular Joint Disorder or TMJ syndrome, describes a variety of problems of the temporomandibular joint. The main factor in TMJ disorders is usually pain related to the jaw. TMJ disorders involve the jaw, jaw joint and surrounding facial muscles that control chewing and movement of the jaw, and they can result in acute or chronic facial pain.
Temporomandibular joint disorder is also known as TMJD, TMJ, TMD and myofacial pain dysfunction. Until recently TMJ disorder was known as Costen’s syndrome. James Costen was the first who described the symptoms of temporomandibular joint dysfunction and linked it to malocclusion (bad bite).
What is the Temporomandibular Joint?
The temporomandibular joint is the joint that connects the lower jaw to the temporal bone of the skull. It is located directly in front of the ear on either side of the head where the upper jaw (maxilla) and lower jaw (mandible) meet. TMJ is one of the most complex and frequently used joints in the human body.
The temporomandibular joint (TMJ) is consisted by the temporal bone (side and base of the skull), the mandible (lower jaw) and the mastication muscles that connect them, allowing the jaw to move smoothly up and down and side to side, and enabling us to talk and chew. The primary muscles involved are the following: temporalis, masseter, medial pterygoid, and lateral pterygoid.
The round upper end of the lower jaw, that is the movable portion of the temporomandibular joint, is called the condyle. The socket where it fits into the temporal bone is called the articular fossa. Between the condyle and the fossa there is a disk made of cartilage that acts as a cushion to absorb stress and allows smooth movement of the joint when the mouth opens and closes.
Most of the problems of the temporomandibular joint are related with the dislocation or damage of this disk between the two jaws, while less cases are related with the muscles providing movement to the temporomandibular joint (TMJ).
The most common symptom of TMJ disorder is pain. TMJ symptoms include :
- Facial pain in the jaw joint area, neck and shoulders, and/or close to the ear when chewing, speaking or opening the mouth wide.
- Limited ability to open the mouth very wide
- Jaw that ‘locks’ in the open or closed mouth position
- Clicking, or popping sounds in the jaw joint when opening / closing the mouth (with or without pain)
- Difficulty or irregular jaw movement while opening and closing the mouth
- Difficulty in chewing . Teeth give the feeling that they are not fitting together properly
- Jaw pain or toothache when waking up after sleep.
Other symptoms of TMJ Dysfunction include:
- TMJ Headaches, that become worse while opening and closing the mouth, are present in most of the Temperomandibular Joint Disorder patients.
- Ear pain in front of or below the ear, but without any signs of infection (hearing loss or ear drainage). Hearing problems like fullness and noise or ringing in the ear (tinnitus) may also be symptoms of TMJD.
- Light sensitivity, hazy visions, pain in and around the eyes, feeling of pressure behind the eyeballs.
Unusual TMJ Symptoms
You may also experience some of the unusual symptoms of TMJ :
- Swelling on the side of the face, in jaw and cheek.
- Other unusual tmj symptoms include toothaches, neckaches, pain in the shoulder and dizziness.
Causes of TMJ Disorder symptoms
There are many different types of TMJ disorder, any one of which may be related to a number of causes. The most common TMJ problems occur when the temporomandibular joint itself or the surrounding muscles are put under intense or continuous stress. Causes of TMJ can be either mental or physical.
The following are some of the causes of TMJ disorders:
- Malocclusion (misalignment of the teeth or bite problem), when the teeth in the upper and lower jaw are not lined up correctly. Malocclusion can result in uneven pressure to each side of the jaw, that puts the muscles and TMJ under stress. For the same reason, chewing on only one side of the jaw can lead to TMJ problems. Modification of the occlusal surfaces of the teeth during dental treatments (if not done properly) may also result in malocclusion problems and cause symptoms of TMJD.
- Bruxism (teeth grinding and teeth clenching). Moving the teeth over each other (teeth grinding) not only wears down the teeth and might cause malocclusion, but also increases the wear on the cartilage lining of the TMJ.
Teeth clenching, when the upper and lower teeth are pressed together putting stress on the facial muscles, tissues and jaw, is a common cause of TMJ syndrome.
Malocclusion and bruxism are the most common causes of TMJ disorders
- Emotional stress is often the underlying cause of a TMJ disorder, as it can contribute to people either consciously or unconsciously tightening facial and jaw muscles and grinding or clenching their teeth.
- Habits like excessive gum chewing or fingernail biting cause jaw muscles overuse.
- External injuries to the temporomandibular joint, jaws, teeth, facial bones or muscles are also causes of TMJ disorders.
- Osteoarthritis or rheumatoid arthritis in the TMJ
- Occupational tasks such as holding the telephone between the head and shoulder.
- Excessive jaw movements like over-opening the jaw beyond its normal range.
Because many other conditions can cause similar symptoms with TMJ, the dentist or physician must take the patient history and perform a careful clinical examination to determine the cause of the symptoms by:
- Physical examination of the temporomandibular joints and their movement.
- Examination of the teeth for signs of malocclusion.
- In some cases diagnosis of TMJ may require :
- Panoramic x-rays, to check for structural problems of the hard tissues.
- Magnetic resonance imaging (MRI), to check also the soft tissues of the TMJ.
Proper diagnosis and identification of TMJ causes is very important for deciding the appropriate treatment for the symptoms of TMJ disorders.
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