Tinnitus in Temporomandibular Disorders patients: any clinical implications from research findings?

Data sources PubMed, the Cochrane Library and the Web of Science databases supplemented by a search of selected textbooks and the reference lists of included papers.Study selection Two reviewers independently selected studies. Studies involving more than ten TMD patients published in English or Swedish were considered.Data extraction and synthesis Two reviewers independently abstracted data and assessed risk of bias using the Joanna Briggs Institute prevalence critical appraisal pool and Newcastle-Ottawa Scale.Results Twenty-five studies were included. Seventeen described the prevalence or incidence in a TMD population, five reported prevalence and treatment outcomes and three treatment outcomes only. Prevalence of tinnitus ranged from 3.7% to 70% (median 42.3%) in TMD patients compared with 1.7% to 26% (median 12%) in control groups. Only one study provided evidence that treatment could improve symptoms compared with no treatment.Conclusions This systematic review found a higher prevalence of tinnitus in patients with TMD compared with the general population. This supports the comorbidity between TMD and tinnitus; however, all but one of the included primary studies on treatment of TMD lacked control groups, which means that future research should target the pathophysiological association.