The effectiveness of manual therapy applied to craniomandibular structures in the treatment of temporomandibular disorders: protocol for a systematic review

Background: The term temporomandibular disorder (TMD) includes disorders of the temporomandibular joints (TMJ), masticatory muscles and adjacent tissues. Several studies have examined the effectiveness of manual therapy (MT) for TMDs by evaluating changes in pain and maximum mouth opening (MMO). Nevertheless, the effectiveness of MT exclusively applied to the craniomandibular structures (craniomandibular manual therapy (CMMT)) on pain and TMJ range of motion remains unclear. This review aims to evaluate the effectiveness of CMMT on pain and TMJ range of motion in people with TMDs. Methods: This protocol is reported in line with the preferred reporting items for systematic reviews and meta-analysis protocols (PRISMA-P). Databases including MEDLINE, Embase, CINAHL, ZETOC, Web of Science, SCOPUS, PEDro, PubMed, Cochrane Library and Best Evidence, EBM reviews-Cochrane Central Register of Controlled Trials, Index to Chiropractic Literature ChiroAccess and Google Scholar will be searched from inception as well as key journals and grey literature. Randomised controlled trials involving adults with TMD that compare the effect of any type of CMMT (e.g. mobilisation) on pain and range of motion with a placebo intervention, controlled care intervention or other types of treatment will be included. Two reviewers will independently screen articles for inclusion, extract data, assess risk of bias (revised Cochrane risk of bias tool) for included studies and evaluate overall quality of evidence (Grading of Recommendations Assessment, Development and Evaluation). A meta-analysis will be conducted if possible. If not, a narrative synthesis will be conducted reporting the effectiveness of CMMT according to disorder type (TMJ disorders, masticatory muscle disorders and mixed disorders). Discussion: In this review, the effectiveness of MT applied to craniomandibular structures for the treatment of TMD will be evaluated. Results will be submitted for publication in a peer-reviewed journal and presented at conferences. We expect our findings will facilitate treatment planning for manual therapists managing patients with TMD and provide future clinical research implications. Systematic review registration: PROSPERO CRD42019160213. Keywords: Manual therapy; Masticatory muscles; Pain; Physical therapy; Temporomandibular disorder; Temporomandibular joint; Temporomandibular joint dysfunction syndrome