Intra-articular temporomandibular joint disorders

Intra-articular disorders - anterior displacement of the articular disc relative to the condylar process. Symptoms: localized pain in the joint and limited jaw movement. Diagnosis is based on anamnesis and special examination methods. Treatment includes analgesics, jaw rest, muscle relaxation, physiotherapy and a bite plate. If treatment is unsuccessful, surgery may be required. Early treatment significantly improves the outcome.

The anterior head of the lateral border of the jaw muscle can displace the articular disc when abnormal mechanical movement of the jaw occurs. Abnormal movement of the jaw can occur due to congenital or acquired asymmetries or as a result of trauma or arthritis. If the disc remains anterior, the disorders remain without reduction. Limitation of jaw movement (stiff jaw) and pain in the ear and around the joint are noted. If the disc returns to the area of the head of the condyle during movement, this is considered without reduction. Disorders with reduction are observed in some cases in about 1/3 of the population. All types of internal disorders can cause capsulitis (or synovitis), which means inflammation of the tissues surrounding the joint (tendons, ligaments, adjacent tissues, capsule). Capsulitis can also develop spontaneously or as a result of arthritis, trauma, infection.

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Symptoms and signs of intra-articular disorders of the temporomandibular joint

Disorders with reduction are usually accompanied by a crunching or clicking sound when opening the mouth. Pain may be present, especially when chewing hard foods. Patients usually think that others around them hear sounds when they chew. Indeed, although the sound seems louder to the patient, others around them can sometimes hear them too.

Disorders without reduction are usually not accompanied by sounds, but the maximum opening of the mouth along the midline between the incisors decreases from the normal 40-45 mm to less than 30 mm. Pain and discomfort when biting are common complaints. In capsulitis, localized pain, soreness and sometimes limitation of opening are noted.

Diagnostics of intra-articular disorders of the temporomandibular joint

Diagnosis of disorders with reduction is observed during movement of the jaw to open the mouth. When the mouth is opened more than 10 mm, a click or crunch or snapping sound is heard as the disc moves along the head of the condyle. During further movement, the condyle remains on the disc. Usually a second click is heard during closing, when the condyle slides along the back surface of the disc and the disc slides forward (mutual click).

Diagnosis of disorders without reduction is observed when opening the mouth as wide as possible. The degree of opening is measured, and light pressure then allows the mouth to open somewhat wider. Normally, the mouth opens by 45-50 mm, if the disc is damaged, the opening will be about 20 mm. Closing or protruding the jaw causes pain.

The diagnosis of capsulitis is based on a history of trauma or infection with mild joint pain, excluding cases where pain occurs during treatment of maxillofacial pain syndrome, disc disorders, arthritis and asymmetries. However, capsulitis can be observed in all of the above conditions.

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Treatment of intra-articular disorders of the temporomandibular joint

A reduction disorder does not require treatment if the patient can open the mouth wide enough (about 40 mm or the height of the index, middle, and ring fingers) without discomfort. If pain is present, mild analgesics such as NSAIDs (ibuprofen 400 mg orally every 6 hours) are prescribed. If the pain has been going on for less than 6 months, an anterior disengaging plate can be used to displace the mandible forward and onto the disc. The plate is made of acrylic plastic and is shaped like the dental arch of one of the jaws. Its chewing surface is designed in such a way that when the jaws are closed, the mandible moves forward. In this position, the disc is always on the head of the condyle. If the disc remains with the condyle on the posterior surface of the head of the condyle near the pterygoid ligament, then in this position the articular disc is pinched. The more the disc is displaced, the more deformed it is and the less likely it is to return to its normal position. Surgical disc relocation may be performed, but with varying success.

Changes in the joint without displacement do not require intervention, except for the administration of analgesics. A plate can help if the articular disc is slightly changed, but long-term use can lead to irreversible changes in the structure of the jaws. In some cases, it is recommended to slowly pull the disc out of its position, which allows the mouth to open normally. Various arthroscopic and open surgical interventions can be performed if conservative treatment is ineffective.

For capsulitis, NSAIDs, jaw rest, and muscle relaxation are initially prescribed. If this treatment is unsuccessful, intra-articular glucocorticoids may be injected or arthroscopic drainage and coils may be used.