Temporomandibular Joint disorder (TMD) is a dysfunction of masticatory muscles and the joints that connect the mandible (lower jaw) to the skull. The foremost symptom of TMD is pain.
Pain in TMD usually occurs in adjacent areas near the tragus or elsewhere on the face rather than in the joint itself. Symptoms vary among individuals, depending on the location of the affected site. These are:
Difficulty of opening the mouth is a common manifestation. Normally, one can open the mouth wide the size of three fingers (index, middle and ring finders) held together and inserted at right angle to the jaws in the space between the teeth. Except for hypermobility, this space is markedly reduced in TMD.
Muscle pain and tightness
Clenching and teeth grinding during the night, when accompanied by sleep apnea can cause myalgia and tightness on the cheeks, with headache on awakening. Stress-related clenching and grinding of teeth at daytime are likewise accompanied by headache . The jaw may be deviated to one side or may be difficult to move at all. Patients usually complain of pain and tenderness of the masticatory muscles.
Internal temporomandibular joint derangement
At the level of the tragus, following reduction of the articular disc, opening the mouth will elicit a peculiar sound of bone snapping against another bony structure. The mandible may glide sideways and pain is felt when chewing hard foods. Persons with missing teeth and who grind their teeth may feel that their jaws are locked.
The articular disc is obliterated or develop holes in arthritis. A scraping sensation is felt, with pain and stiffness upon opening and closing the mouth. When the upper surface of the jawbone becomes completely eroded in severe arthritis, the patient will have difficulty opening the mouth wide. The jaw may be deviated to one side and can not be moved back in place.
Pain and inflammation limit the movement of both temporomandibular joints in rheumatoid arthritis. In advanced rheumatoid arthritis, as in children, the jawbone becomes degenerated and shrinks, disfiguring the face. At its worst, the teeth become misaligned and the mandible fuses with the skull (ankylosis).
The entire joint is inflamed in infectious arthritis, accompanied by pain and limited mandibular movement. Tenderness, pain and limited jaw movement likewise characterize TMD in traumatic arthritis.
In extra-articular ankylosis, the ligaments around the joint become calcified and although not painful, limit opening of the mouth only about 1 inch wide (about 2.5 centimeters) or less. In the case of intra-articular ankylosis the bones within the joint may fuse, causing pain and severely limiting jaw movement.
Hypermobility occurs when the jaw becomes dislodged from the fossa, accompanied by pain and difficulty of closing the mouth. This may recur suddenly.
The area in front of the tragus is palpated for tenderness with the index finger, while the patient is asked to open and close the mouth. A stethoscope is placed over the area to detect clicks of crepitus. The jaw is examined for deviation on either side or for jerky movements. These are signs of internal derangement. Worn facets on the teeth indicate bruxism or clenching .
A panoramic radiograph of the joint (including the mandibular condyles), ultrasonography and/or MRI can confirm crepitus. Presence of degenerated condylar bone indicates osteoarthritis. However, ultrasound can not visualize lateral and posterior aspects of the derangement of the articular disc . Differential diagnosis of inflammation requires additional clinical laboratory tests e.g., rheumatoid factor, C-reactive protein, complete blood count, and erythrocyte sedimentation rate when a co-existing autoimmune disease is suspected.
Temporomandibular joint disorder may heal spontaneously. Pain and other symptoms may disappear in time without treatment. In persistent cases with increasing severity, a number of rehabilitative options are available.
Joint rest is prescribed to relax the masticatory muscles and to minimize mandibular condyle movement. The patient is advised to refrain from biting on hard objects, chewing gum, or talking excessively. Soft diet is recommended. Counselling is initiated to reduce stress in the case of bruxism or clenching. Cognitive behavioral therapy as a first-line treatment has been successful in a controlled study. This was found to be more effective in alleviating symptoms and in improving patient's pain-coping skills than occlusal splint therapy . Psychosocial methods on the management of orofacial pain are recommended for long-term pain and depression control .
Exercises in opening and closing the mouth in a straight line can be initiated by the patient as physiotherapy, with the tongue touching the palate and guided by a mirror.
Hard stabilization devises such as splints, intra-oral braces, bite guards, and night-guards may be more effective than soft therapeutic aids for use by patients. The effectiveness of splints in repositioning the mandibular condyles and in modifying oral habits of patients remains to be confirmed. Although splint therapy was found useful in pain control, it has not been shown to improve symptoms associated with chewing .
The strategy on pharmacological therapy consists of 2 weeks of complete joint rest. If symptoms persist, medications can be initiated and followed up for another 2 weeks of rest.
Non-steroidal anti-inflammatory drugs (NSAIDs) are appropriate for internal derangement and other subtypes of osteoarthritis in TMD. However, NSAIDS are not effective in myofascial pain since chronic muscle pain in the orofacial region is not due to inflammation.
Diazepam, a muscle-relaxant, is an effective analgesic in treating TMD when given for 10 days followed by a prescribed 2-week period of joint rest. Diazepam should be used with caution since it can cause drowsiness and drug dependence.
Patients with persistent pain and pathological signs may need surgical intervention. The options are: arthrocentesis, condylotomy, and total joint replacement. Studies show that arthroscopy is more effective than arthrocentesis in reducing pain and improving interincisal opening after 12 months. There are also indications that open surgery is more effective than arthroscopy in reducing pain after 12 months . Patients who are not relieved by conventional therapy and presenting evidence of progressive disabling disease may need to undergo surgery.
In most cases the clinical manifestations of temporomandibular joint disorder may disappear with age without treatment . Bruxism may resolve in time . The rationale of treatment is in the application of palliative measures; 80%of patients can be expected to benefit from this approach .
Daily habits, accidents, aging, and co-existing diseases can predispose to temporomandibular joint disorder .
Trauma: Microtrauma and macrotrauma are common occurrences. Examples of microtrauma are grinding of the teeth (bruxism) and clenching (jaw tightening), which can cause misalignment of the teeth and inflammation of surrounding soft tissues. These habits have been found to cause pain in TMD patients and others who have myofascial pain, which is associated with chewing. Macrotrauma or pain inflicted by a hard blow to the jaw or from an accidental can dislocate the jawbone or damage the articular disc. Keeping the mouth wide open and stretching the joint for a long time when doing dental procedures can elicit pain as well. Massaging the affected area and application of warm compress are palliative.
Bruxism: Teeth grinding causes muscle spasm, inflammation and pain. Some persons exhibit this habit during sleep. Misalignment of teeth and excessive use of masticatory muscles may cause detrimental changes in the joint.
Clenching: Chewing gum or biting into something (pencil, fingernails) when under stress can elicit pain in TMD.
Osteoarthritis: Degenerative changes in the joint due to arthritic disease occurs in the elderly. These result in incremental loss of cartilage and new bone growth in the joint. Mechanical and biological factors can cause cartilage destruction. The disorder worsens with age and with repeated injury sustained from trauma. Immunologic and inflammatory processes are involved.
Rheumatoid arthritis: Rheumatoid arthritis, an autoimmune disease, is characterized by joint inflammation and can predispose to TMD, especially in children. The disease causes bone abrasion, joint deformity and further deterioration of cartilage
Psychogenic factors and stress presumably exacerbate TMD. The possible role of hormones is being considered since cases are commonly found in women. Researchers are looking into a link with malocclusion .
Temporomandibular joint disorders occur in people in all age groups. About 6-12% of the adult population are symptomatic. Women in early adulthood are more frequently affected than men .
Three subtypes of TMD involve specific areas, with slightly different symptoms. Myofascial pain and dysfunction originate from the masticatory muscles resulting from bruxism or clenching. These muscles are vulnerable to overuse and tenderness, causing difficulty of mandibular movement and opening of the mouth. Headache develops in the temporal region of the head . The onset of myofascial pain oftentimes occurs with the nocturnal habit of bruxism during sleep. Tooth ache and worn facets may result from bruxism and clenching .
The articular disc is diverted from its normal placement in the glenoid fossa when the mandibular condyle moves and attaches to it. This reduces the surface area occupied by the disc in the fossa, loses the smooth (frictionless) movement within the joint, causing clicking sound and pain . The derangement of the disc, in turn, displaces the condyles from the glenoid fossa, thereupon making the patient feel as if the jaw is locked .
Osteoarthritis in the elderly causes degradation of the disc. Pain with crepitus, a pathognomonic sign of osteoarthrosis, likewise occurs in TMD. Three-dimensional radiographs or CT scan can show degeneration of the condyles in osteoarthritis .
Since stress and habits are probably the most important predisposing factors in TMD, prevention depends to a large extent on the individual's initiative to rehabilitate himself/herself. Knowing the cause of the disorder is a step towards its resolution. Bruxism and clenching of teeth can be avoided. Oral hygiene and maintenance of good dentition can minimize impingement on the lower jaw. Medications (muscle relaxants) and devices to maintain stability of the joint can be used to alleviate symptoms. A healthy lifestyle, diet, exercise and counselling from a healthcare provider are good measures for prevention.
Temporomandibular joint disorder (TMD or TMJ) is a condition, characterized chiefly by pain and involving the juncture between the mandible and os temporale. A cartilaginous disc prevents friction at the point of articulation between the two osseous structures. This anatomical arrangement serves like a hinge, allowing the mandible to move in all directions while the person is eating, talking or yawning.
As it is, the temporomandibular joint is subject to considerable mechanical pressure in the process of chewing and even when the mouth is closed. The integrity of the joint likewise depends on the position of the teeth. Malocclusion may impose additional stress on the joint.
The principal sites that are affected are the articular surface, the articular disc, or articulating bones , and the masticatory muscles. TMD is more of a complex of symptoms and treatment relies on identifying the origin of pain, so that a corresponding therapeutic approach can be prescribed .
TMD is usually a self-limiting disorder and much depends on the individual's initiative to observe and avoid the conditions that cause the disorder. Treatment, if needed, consists of pharmacological and non-pharmacological therapy, and surgery, when medically indicated.
Temporomandibular disorder (TMD) is a condition involving the connection between the lower jaw (mandible) and the base of the skull. Pain is the most prominent symptom. The course of illness ranges from self-limiting to severe, necessitating medical intervention.
Possible causes of TMD
Several factors contribute to the development of TMD. The two main structures that are affected are the muscles associated with joint movement, such as in chewing or speaking and the interconnections within the joint itself. The most common problem involves the muscles, which occurs among young persons and the elderly.
The origin of symptoms from the muscles are:
Pathogenic changes in the joint are:
Symptoms of temporomandibular joint disorder:
Diagnosis is based on personal interview, thorough physical examination and medical history in order to identify the possible causes of the disorder. Laboratory examination and imaging studies may be needed to ascertain the presence of predisposing factors. Consultation with an oral and maxillofacial specialist, or otolaryngologist, or a dentist specializing in jaw disorders is recommended to confirm the diagnosis. X-ray, ultrasound or MRI of the temporomandibular joint are used to assess the status of the joint and to rule out other diseases.
Trigeminal neuralgia is another disorder that sends nerve impulses to the joint. When stimulated, it can trigger facial pain in TMD. Other sources of facial or neck pain that need to be differentiated from TMD are: lymphadenitis (swollen lymph nodes), salivary gland disease, sore throat, giant cell arteritis, ill-fitting dentures, or dental braces.
Minimize pressure on the jaw by shifting to a soft diet, refraining from chewing gum, singing, and yawning too widely. Massage and warm compress are soothing.
Relax with oral medication and stress-reducing therapies. Stress elicits pain.
Bite guards are recommended for nighttime teeth clenching.
Oral analgesics e.g., ibuprofen, paracetamol, or codeine can relieve pain.
Muscle relaxants or a small dose of a tricyclic antidepressant can reduce stress.
To augment current treatment modalities and for long-term recovery from the disorder, the following are recommended: physiotherapy, ultrasound and gentle jaw exercises.
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Ebrahim S, Montoya L, Busse JW, et al. The effectiveness of splint therapy in patients with temporomandibular disorders: a systematic review and meta-analysis. J Am Dent Assoc. 2012; 143:847-857.
Rigon M, Pereira LM, Bortoluzzi MC, et al. Arthroscopy for temporomandibular disorders. Cochrane Database Syst Rev. 2011; (5):CD006385.