Psychological therapies for temporomandibular disorders (TMDs)

BACKGROUND: Temporomandibular disorders (TMDs) are a group of musculoskeletal disorders affecting the jaw. They are frequently associated with pain that can be difficult to manage and may become persistent (chronic). Psychological therapies aim to support people with TMDs to manage their pain, leading to reduced pain, disability and distress. OBJECTIVES: To assess the effects of psychological therapies in people (aged 12 years and over) with painful TMD lasting 3 months or longer. SEARCH METHODS: Cochrane Oral Health's Information Specialist searched six bibliographic databases up to 21 October 2021 and used additional search methods to identify published, unpublished and ongoing studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) of any psychological therapy (e.g. cognitive behaviour therapy (CBT), behaviour therapy (BT), acceptance and commitment therapy (ACT), mindfulness) for the management of painful TMD. We compared these against control or alternative treatment (e.g. oral appliance, medication, physiotherapy). DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. We reported outcome data immediately after treatment and at the longest available follow-up. We used the Cochrane RoB 1 tool to assess the risk of bias in included studies. Two review authors independently assessed each included study for any risk of bias in sequence generation, allocation concealment, blinding of outcome assessors, incomplete outcome data, selective reporting of outcomes, and other issues. We judged the certainty of the evidence for each key comparison and outcome as high, moderate, low or very low according to GRADE criteria. MAIN RESULTS: We identified 22 RCTs (2001 participants), carried out between 1967 and 2021. We were able to include 12 of these studies in meta-analyses. The risk of bias was high across studies, and we judged the certainty of the evidence to be low to very low overall; further research may change the findings. Our key outcomes of interest were: pain intensity, disability caused by pain, adverse events and psychological distress. Treatments varied in length, with the shortest being 4 weeks. The follow-up time ranged from 3 months to 12 months. Most studies evaluated CBT. At treatment completion, there was no evidence of a benefit of CBT on pain intensity when measured against alternative treatment (standardised mean difference (SMD) 0.03, confidence interval (CI) -0.21 to 0.28; P = 0.79; 5 studies, 509 participants) or control (SMD -0.09, CI -0.30 to 0.12; P = 0.41; 6 studies, 577 participants). At follow-up, there was evidence of a small benefit of CBT for reducing pain intensity compared to alternative treatment (SMD -0.29, 95% CI -0.50 to -0.08; 5 studies, 475 participants) and control (SMD -0.30, CI -0.51 to -0.09; 6 studies, 639 participants). At treatment completion, there was no evidence of a difference in disability outcomes (interference in activities caused by pain) between CBT and alternative treatment (SMD 0.15, CI -0.40 to 0.10; P = 0.25; 3 studies, 245 participants), or between CBT and control/usual care (SMD 0.02, CI -0.21 to 0.24; P = 0.88; 3 studies, 315 participants). Nor was there evidence of a difference at follow-up (CBT versus alternative treatment: SMD -0.15, CI -0.42 to 0.12; 3 studies, 245 participants; CBT versus control: SMD 0.01 CI - 0.61 to 0.64; 2 studies, 240 participants). There were very few data on adverse events. From the data available, adverse effects associated with psychological treatment tended to be minor and to occur less often than in alternative treatment groups. There were, however, insufficient data available to draw firm conclusions. CBT showed a small benefit in terms of reducing psychological distress at treatment completion compared to alternative treatment (SMD -0.32, 95% CI -0.50 to -0.15; 6 studies, 553 participants), which was maintained at follow-up (SMD -0.32, 95% CI -0.51 to -0.13; 6 studies, 516 participants). For CBT versus control, only one study reported results for distress and did not find evidence of a difference between groups at treatment completion (mean difference (MD) 2.36, 95% CI -1.17 to 5.89; 101 participants) or follow-up (MD -1.02, 95% CI -4.02 to 1.98; 101 participants). We assessed the certainty of the evidence to be low or very low for all comparisons and outcomes. The data were insufficient to draw any reliable conclusions about psychological therapies other than CBT. AUTHORS' CONCLUSIONS: We found mixed evidence for the effects of psychological therapies on painful temporomandibular disorders (TMDs). There is low-certainty evidence that CBT may reduce pain intensity more than alternative treatments or control when measured at longest follow-up, but not at treatment completion. There is low-certainty evidence that CBT may be better than alternative treatments, but not control, for reducing psychological distress at treatment completion and follow-up. There is low-certainty evidence that CBT may not be better than other treatments or control for pain disability outcomes. There is insufficient evidence to draw conclusions about alternative psychological therapeutic approaches, and there are insufficient data to be clear about adverse effects that may be associated with psychological therapies for painful TMD. Overall, we found insufficient evidence on which to base a reliable judgement about the efficacy of psychological therapies for painful TMD. Further research is needed to determine whether or not psychological therapies are effective, the most effective type of therapy and delivery method, and how it can best be targeted. In particular, high-quality RCTs conducted in primary care and community settings are required, which evaluate a range of psychological approaches against alternative treatments or usual care, involve both adults and adolescents, and collect measures of pain intensity, pain disability and psychological distress until at least 12 months post-treatment.