A systematic review of the effectiveness of conservative therapy in the treatment and management of temporomandibular joint disorders

Background: Temporomandibular disorders (TMD) encompass neuromusculoskeletal conditions affecting the temporomandibular joint (TMJ) and surrounding orofacial structures, particularly the muscles of mastication. Despite numerous treatment options, there is a dearth of evidence-based conservative interventions. This systematic review aims to evaluate the level of evidence for conservative TMD interventions to inform clinical practice guidelines. Methods: A systematic search was conducted across databases including CINAHL, Cochrane Library, Medline, PubMed, ScienceDirect, Scopus, and Web of Science, supplemented by a hand search. The final search was completed on June 2022 and a supplementary search was performed in March 2023. Inclusion criteria encompassed studies evaluating conservative therapies for TMD in human subjects, while exclusion criteria included non-English studies, unavailable full texts, and studies not focused on conservative treatments. Risk of bias was assessed using the PEDro scale for RCTs, the Newcastle-Ottawa scale (NOS) for NRCTs, and the Liddle scale for case reports and series. Data were synthesized qualitatively. This review was registered in PROSPERO (CRD42023409560). Results: From 4,148 records, 789 duplicates and 3 retracted articles were removed. Title screening excluded 3,141 articles, abstract screening excluded 172 articles, and full-text screening excluded 9 articles, leaving 31 eligible articles. An additional study identified through a hand search brought the total to 32, comprising 19 RCTs, 10 NRCTs, 1 case report, and 2 case series. The interventions evaluated included dry needling, exercise, physical therapy, ischemic compression, manipulation/mobilisation, and manual therapy. Strong evidence supports the effectiveness of dry needling, while moderate evidence was found for exercise, manual therapy, and multimodal interventions, such as cervical spine manipulation combined with other therapies. Limited evidence supports thoracic spine manipulation, myofascial techniques, physical therapy, and proprioceptive neuromuscular facilitation. Conclusion: These findings highlight the potential benefits of conservative therapies in TMD management. Clinicians should prioritize dry needling, exercise, and manual therapy, particularly in combination with other modalities, to optimize patient outcomes. Researchers should focus on conducting high-quality RCTs with standardized protocols and larger sample sizes to strengthen the evidence base, particularly for under-researched interventions such as thoracic spine manipulation and proprioceptive neuromuscular facilitation. Policymakers should consider integrating the strongest evidence-based interventions into clinical guidelines to improve accessibility and standardization of conservative TMD treatments