Effect of Manual Therapy and Therapeutic Exercise Applied to the Cervical Region on Pain and Pressure Pain Sensitivity in Patients with Temporomandibular Disorders: A Systematic Review and Meta-analysis

Objective. To assess the effectiveness of cervical manual therapy (MT) on patients with temporomandibular disorders (TMDs) and to compare cervico-craniomandibular MT vs cervical MT. Design. Systematic review and meta-analysis (MA). Methods. A search in PubMed, EMBASE, PEDro, and Google Scholar was conducted with an end date of February 2019. Two independent reviewers performed the data analysis, assessing the relevance of the randomized clinical trials regarding the studies' objectives. The qualitative analysis was based on classifying the results into levels of evidence according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE). Results. Regarding cervical MT, MA included three studies and showed statistically significant differences in pain intensity reduction and an increase in masseter pressure pain thresholds (PPTs), with a large clinical effect. In addition, the results showed an increase in temporalis PPT, with a moderate clinical effect. MA included two studies on cervical MT vs cervico-craniomandibular MT interventions and showed statistically significant differences in pain intensity reduction and pain-free maximal mouth opening, with a large clinical effect. Conclusions. Cervical MT treatment is more effective in decreasing pain intensity than placebo MT or minimal intervention, with moderate evidence. Cervico-craniomandibular interventions achieved greater short-term reductions in pain intensity and increased painfree MMO over cervical intervention alone in TMD and headache, with low evidence.