Frequency of temporomandibular arthralgia among myofascial pain patients with pain on palpation of ipsilateral masseter

AIMS: The masseter muscle is a common source of referred pain to the temporomandibular joint (TMJ), with a possibility of false positive diagnoses for arthralgia when diagnosed by research diagnostic criteria for temporomandibular disorders (RDC/TMD) clinical examination. The current study investigated the distribution of arthralgia diagnoses among individuals with myofascial pain, with or without pain on masseter palpation. METHODOLOGY: The study was conducted with 255 outpatients. Clinical data and questionnaires were directly entered into software that deploys algorithms based on the diagnostic criteria of the RDC/TMD, and automatically classifies and stores the diagnosis of each patient evaluated. An association between diagnostic subgroups was verified by calculating the odds ratio (OR), and the statistical significance was tested using the Chi-square test. RESULTS: A higher frequency of concordance (about three times greater) between myofascial pain and arthralgia occurred when there was pain on palpation in the region of the ipsilateral masseter muscle, and the association was statistically significant. CONCLUSIONS: The results of this study revealed a threefold increase in the risk for the presence of temporomandibular arthralgia in cases of myofascial pain combined with pain on palpation in the region of the ipsilateral masseter muscle.