Inflammatory joint diseases can affect the temporomandibular joint (TMJ) but there has been uncertainty to what extent. Most common are rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PS). Especially RA can cause a handicapping situation both generally and in the TMJ, which can cause difficulties in coping with ordinary life situations. The knowledge about long-term development in the TMJ and the relation of disease activity is not clearly documented. The aim of the first two studies was to compare RA, AS and PS with healthy controls without general joint or skin disease with respect to radiographic changes in the TMJ, subjective symptoms and clinical findings in the masticatory system. Panoramic images were performed to examine both TMJ condyles. Deviation in shape and changes of cortical outlines were recorded. Subjective symptoms and clinical and radiological findings were significantly more frequent in the disease groups than in the control groups. Pain, morning stiffness and reduced mouth opening capacity were most frequent and in RA followed by PA and AS. Signs and findings were mainly caused by the general disease and they were more common in RA than in PA and AS. In study 3, the aim was to investigate if RA patients differ from patients with temporomandibular disorders (TMD) and without general inflammatory joint disease (C group) regarding subjective symptoms, general well-being and selfrated physical health. The results showed that the RA group had fewer symptoms than the C group and they rated their mental well-being as normal while the C group showed higher tension, stress and muscle activity. In self-rated discomfort, the RA group reported as high results concerning TMJ and general joint pain, but not in general. The aim of Study 4 and Study 5 was to investigate the long term development (15 years) of the RA group concerning subjective symptoms, clinical findings, general well-being, radiological changes, alveolar approximal bone loss (ABL) and medical data. The RA group reported no changes on subjective symptoms and discomfort while the well-being had deteriorated. There was a significant increase in muscle and neck tenderness, reduced vertical overbite and reduced number of teeth. There was significant radiological impairment in the TMJ and ABL in the RA group. The disease activity stayed on a medium level, indicating a generally stable situation for these patients, although the temporomandibular system had degraded. In spite of the degradation, the RA patients seemed capable of handling problems from this system. The C group was stable which indicates a good prognosis after 15 years regarding the temporomandibular system, while their opinion of their physical health had degraded. They were not affected in the TMJ and ABL in the long term in this study.