Effect of adjunctive intraoral balance appliance in the usual care of patients with chronic temporomandibular joint disorders using Korean medicine in South Korea: Study protocol for a randomised controlled trial

Introduction Temporomandibular disorders (TMDs) are a group of conditions affecting the temporomandibular joint (TMJ), masticatory muscles and associated structures, often leading to pain, dysfunction and a significant impact on quality of life. Epidemiological studies have estimated that up to 75% of the population in the USA exhibits at least one sign of TMD. Although conservative treatments, such as acupuncture and occlusal splints, have been recommended, evidence for their effectiveness remains inconclusive, and the combined effects of these interventions are not well understood. This study aims to evaluate the efficacy of an intraoral balance appliance (IBA) combined with standard Korean medicine care, compared to Korean medicine care alone, in patients with chronic, painful TMD with myalgia. Methods and analysis A single-centre, two-arm, parallel, practitioner-blinded and evaluator-blinded, randomised controlled trial with a 1:1 allocation ratio will be designed to test the interventions. 76 patients with TMD with myalgia will be recruited and randomised. The interventions will include manual acupuncture and physical therapy for both groups, with the addition of IBA in the treatment group for 3 weeks. The primary outcomes of the study will be the Numeric Rating Scale (NRS) for pain and discomfort at the final visit at week 4. Secondary outcomes will include overall functional assessment of the TMJ using several scales, as well as evaluations of quality of life, patient satisfaction and AEs. The recruitment started on 18 July 2024, and 37 patients were included as of 8 July 2025. Ethics and dissemination Ethical approval is obtained from the Kyung Hee University Korean Medicine Hospital Institutional Review Board (IRB number: KOMCIRB 2023-06-001). The result from this study will be actively disseminated through manuscript publications and conference presentations.