Temporomandibular joint involvement in rheumatoid arthritis. A clinical study

The aims of this thesis were to investigate individuals with rheumatoid arthritis (RA) with respect to the frequency and character of temporomandibular joint (TMJ) disorder, the relationship between TMJ involvement and general joint disease, the possibility to detect pathologic conditions in the TMJ region with skin surface temperature, and treatment effect of physical training on TMJ disorder. TMJ disorder was more frequent and more severe in RA than among normal subjects. The TMJ symptoms started frequently in the early phase of RA and were correlated to the extension of the general joint symptoms. Anterior open bite occurs in a small subgroup of RA individuals and was associated with severe TMJ disorder and high values of ESR. High concentration of serum acute-phase reactants and high values of rheumatologic indices were associated with severe TMJ involvement in RA. Skin surface temperature over the TMJ and the masseter muscle was generally low in individuals with RA compared with normal subjects. TMJ disorder was related to the overlying skin surface temperature. The low temperature over the TMJ and the masseter muscle is probably caused by disuse atrophy and an ensuing decrease in muscular blood flow. Short-term results of physical training for the stomatognathic system improved the mandibular mobility and reduced the clinical dysfunction in RA.