Effects of Physiotherapy on Pain and Mouth Opening in Temporomandibular Disorders: An Umbrella and Mapping Systematic Review with Meta-Meta-Analysis

The aim of this meta-meta-analysis was to assess the current evidence regarding the effect of physical therapy (PT) interventions on pain and functional variables in temporomandibular disorders (TMD). We conducted an umbrella systematic review (SR) and four meta-meta-analyses (MMA) and created an evidence map to determine the effectiveness of PT on pain intensity and maximum mouth opening in patients with TMD. The quality of the included SR was assessed with the AMSTAR 2, and the risk of bias with ROBIS. Of the 31 SR included in the umbrella SR, only 10 were included in the MMA. The MMA showed moderate effects for manual therapy and therapeutic exercise, and large effects for low-level laser therapy on improving pain intensity and maximum mouth opening in patients with TMD, with a limited to moderate quality of evidence. The overlapping analyses showed only a slight overlap for all the MMA according to the corrected covered area (range from 0.07 to 0.2), 23.1% to 41.6%. This umbrella SR showed that manual therapy and exercise interventions, as well as low-level laser therapy interventions, are effective in the reduction in pain intensity and improvement of maximum mouth opening in TMD. This article presents a synthesis of the available evidence related to the various physical therapy interventions used in patients presenting with temporomandibular disorders. These results could help clinicians to select the optimal intervention for their patients and to reject those that are less useful.