Temporomandibular Disorders: Osteoarthritis

The musculoskeletal system may be affected by more than 100 different diseases. Several also involve the temporomandibular joint (TMJ) and masticatory muscles and are associated with symptoms of temporomandibular disorders (TMD). Dentists' knowledge in this area has been limited and regrettably beset with problems of definition and reliability of measures. This has compromised the merits of many past reports, since the use of diagnostic labels has often verged on overdiagnosis. In recent years, an emerging body of clinical and basic science information, coupled with strong academic resolve, has yielded intellectual rigor in the understanding and management of TMD. It has also permitted the introduction of a limited diagnostic classification, which recognizes 3 major groups of TMD diagnosis. These are: I. muscle diagnoses, II. disc displacements, and III. arthritis. The Dworkin and LeResche classification is a non-hierarchical one, and it conveniently recognizes the most frequently encountered TMD in clinical practice. It was originally proposed for clinical and epidemiologic research purposes, but it has proven to be a very useful clinical teaching and patient management tool. This paper reviews salient aspects of Group III, or TMD that are arthritis-related. Osteoor degenerative arthritis (OA) is a non-inflammatory disease of moveable joints. It is generally regarded as the result of a time-dependent pattern of joint reactions to injury, rather than as a single entity. It is mainly a disease of articular cartilage that produces symptoms in single body joints. It also can affect the TMJs, whose articular surfaces are covered with fibrocartilage rather than hyaline cartilage. While the disease can be crippling, leading to a vast range of morphologic and functional deformities, it very rarely affects the TMJs to such a dramatic extent. The disease process is characterized by deterioration and abrasion of articular cartilage and soft tissue surfaces, the occurrence of thickening and remodeling of the underlying bone, and formation of marginal spurs and subarticular "cysts." Such changes are very common in many joints in older people but are often asymptomatic. These changes are, however, frequently accompanied by the superimposition of secondary inflammatory changes, which can cause symptoms. It should be emphasized that the general physical health of the individual is seldom affected by the disease, in spite of its widespread nature and the risk of multiple joint involvement. Nevertheless, it has been stated that OA may account for more disability among the elderly than any other disease, not because individuals with OA are severely disabled, but because the disease is disabling in so many. This statement sounds particularly ominous when it is considered that OA affects 1 in 10 Canadians or Americans and that, by age 70, 85% of the population is likely to be affected. Osteoarthritis has been generally regarded as inevitably progressive once it has become clinically symptomatic. More recent findings, however, sup- port the concept of reversibility of OA, and the sooner treatment is started, the more effective it will be. The progression of severity of TMJ arthritis is not known, but it is not regarded as being likely to lead to serious disability.

osteoarthritis; osteoarthrosis; temporomandibular disorders; clinical management; arthralgia; temporomandibular joint; crepitation