Occlusal Adjustment vs Placebo for Chronic Temporomandibular Disorders. The MAP Randomized Clinical Trial

Importance: Evidence regarding effective treatments for temporomandibular joint disorders (TMDs) is limited. Objective: To determine whether occlusal adjustment may reduce the pain intensity of patients with chronic TMD. Design: The MAP study was a phase 3 randomized, participant- and assessor-blinded, placebo-controlled trial of a novel occlusal therapy for chronic TMD over the course of 6 months. It was carried out from August 4, 2014 to October 25, 2018 (last 6-month follow-up). Setting: Single referral tertiary care hospital. Therapies were performed in a University Clinic in a different city. Participants: From 924 adult patients screened diagnosed as TMD, 820 were excluded (partial tooth loss, no chronic condition, malocclusion); 27 declined to participate. Seventy-seven participants underwent randomization; all but one female participant completed the analysis. Interventions: Participants were randomly (1:1) assigned to occlusal adjustment therapy (N=39) or similar placebo (N=38) that did not remove any enamel. Main Outcome and Measure: Primary outcome (before data collection began): change in pain score (in a 0-10 points visual analogue scale) from baseline to the 3- and 6-month assessments. Because one majority of the 1-month therapy visits (carried out in a city 70 km away) were delayed nearest the 3-month visit, the actual primary outcome was the average pain intensity improvement at 6 months in respect of the baseline scores (05/05/2016 ISRCTN amendment). Clinical important difference 1.5 points. Results: The trial was stopped early for efficacy. This report includes all randomized participants in their originally assigned group: 39 to occlusal adjustment and 38 to placebo therapy. Both groups were balanced regarding baseline characteristics. As compared with the placebo, occlusal adjustment reduced jaw pain intensity (adjusted mean difference, -1.54; 95% confidence interval [CI] -.5 to -2.6; P=0.004; ANCOVA model). Conclusions and Relevance: The occlusal adjustment was effective in treating chronic TMD pain and improved limited mouth opening in comparison with the placebo over a 6-month period. The results of this trial are provisional and should not be generalized to patients with different dental conditions, or if the therapies are provided by less experienced dental professionals.