This study was conducted to evaluate whether integrating a nociceptive trigeminal inhibition-tension suppression system (NTI-tss) device with first-line therapy of myofascial pain, which includes guidance, assurance, counselling and behavioural changes, would be more effective in alleviating symptoms. This randomised controlled clinical trial included 40 patients who were clinically diagnosed with myofascial pain according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Patients were randomly divided into two groups: the first group comprised patients who received guidance, assurance, counselling and behavioural changes; an NTI-tss device was integrated to this protocol in the second group. Both groups exhibited reduction in pain levels and improvement of jaw function compared with baseline values, but the difference was not significant. Both groups demonstrated improvements in 6 weeks; however, the integration of NTI-tss device into the therapy protocol did not provide any additional benefit in relieving symptoms of myofascial pain.