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X-ray diagnostics of temporomandibular joint diseases
Last reviewed: 19.10.2021
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The complexity of the anatomical structure and the function of the temporomandibular joint, the relationship of the latter with the state of the occlusion and the masticatory muscles, the absence of a direct relationship between the clinical picture and radiographic changes cause considerable difficulties in recognizing the diseases of this junction. In 70-80% of cases, pathological processes in the joint are associated with the pathology of its soft tissue components - the joint disc, intraarticular ligament and capsule. Based on the results of studies using highly effective technologies (contrast arthritomography, X-ray computer arthritomography, magnetic resonance imaging, arthroscopy), a classification of temporomandibular joint diseases is proposed.
Deforming arthrosis. Dystrophic changes in the joint are among the most frequently observed lesions resulting from abnormalities of closure, articulation, tone of the masticatory musculature, hormonal and endogenous disorders, trauma.
Deforming arthrosis begins with the development of degeneration of articular cartilage, which leads to their thinning, cracks, destruction. Along with defects and deformation of the articular disc, adhesion of the disc to the head and posterior sting of the articular tubercle is noted, which arises as a result of the adhesion process. The detected parts of the bone slide along each other during movement. In the most loaded subchondral parts of bones, osteosclerotic reconstruction (subchondral sclerosis) of the end plate occurs. In connection with the appearance of additional marginal bone growths at the attachment sites of ligaments and muscles, the area of articulating bones increases and, as a consequence, the pressure decreases per unit area. The marginal bony growths first arise in the region of the articular cavity, and then in the articular head.
Deforming arthrosis is sometimes manifested by somewhat greater mobility in the joint (anterior subluxation). The most characteristic symptoms of deforming arthrosis are a narrowing of the x-ray joint gap, sclerosis and an increase in the intensity of the cortical closure plates of the head and the posterior stump of the articular tubercle. In this case, the function of the joint is impaired: the tour of the head is limited, there are less likely dislocations and subluxations.
With deforming arthrosis there are changes in the shape of the head and articular tubercle: flattening and erasing the head in height, pointed or clavate deformation and the formation of exophytes, flattening of the tubercle or exophytic formations on it.
Similar clinical symptoms can be observed with changes in the position of the disc. In these cases, diagnosis is facilitated by the introduction of a contrast agent (arthrography) in the joint in conjunction with the performance of computer tomograms or magnetic resonance imaging without contrasting.
Arthritis. Inflammatory processes in temporomandibular joints develop less often. Infection of the joints can occur with childhood infections, the spread of the inflammatory process to the bone elements of the joint, osteomyelitis of the lower jaw, parotitis, otitis, and trauma.
The first sign of inflammation of the joint is a pronounced impairment of the mobility of the head, after 15-20 days, osteoporosis and uneven narrowing of the x-ray joint gap occur. Cortical closure plates in some areas lose their clarity, the edge head usurp and the posterior edge of the tubercle are revealed.
The death of the disc and articular cartilage in children and adolescents leads to the development of bone ankylosis. In these cases, the image of the x-ray joint gap in the image is missing completely or partially, the structure of the bone tissue of the head passes to the bone tissue of the joint cavity. The function of the joint is absent.
Ankylosis in early childhood leads to disruption of the growth of the lower jaw on the side of the lesion and deformation of the maxillofacial region. For the distinctive recognition of bone ankylosis and deforming arthrosis, fibrotic ankylosis, it is necessary to perform tomograms in the direct and lateral projections.
The defeat of temporomandibular joints is detected in 50% of patients with rheumatism. In the initial stages, only a violation of the mobility of the head is noted radiologically, with exacerbation, osteoporosis of the joint elements, unclear cortical plates, narrowing of the joint gap, and limitation of the mobility of the head. Later these changes serve as a background for the development of degenerative-dystrophic changes.
Arthritis of the temporomandibular joint, developing in 60% of patients with Bechterew's disease, causes fibrotic or bone ankylosis with loss of joint function.