Skin surface temperature over the masseter muscle in individuals with rheumatoid arthritis

Temperature measurements were made on the skin surface over the masseter muscle in 71 individuals with rheumatoid arthritis (RA group) and in 52 individuals without general joint disease or symptoms (C group). The temperature recordings were performed with thermistors in contact with the skin. Symptoms in the stomatognathic system and general joint symptoms were investigated by means of a questionnaire. A clinical examination was made of the stomatognathic system. In addition, a medical examination including clinical articular indices and laboratory tests was made. The skin surface temperature over the masseter muscle was generally decreased for the individuals with RA compared with the C group but increased with duration of temporomandibular joint (TMJ) symptoms, approaching normal values. Duration was also the most important variable among those investigated in determining the skin surface temperature over the masseter muscle. Hypothermia in the RA group was correlated with craniomandibular disorders such as lateral deviation of the mandible on mouth opening and TMJ clicking, whereas individuals with a history of swelling in the TMJ region had a higher temperature than average in this group. The results of this study show that there is a correlation between craniomandibular disorders and decreased skin surface temperature over the masseter muscle in individuals with RA.