The Co-Occurrence of Temporomandibular Disorders in Patients Diagnosed with Tinnitus: A Systematic Review with Meta-Analysis

Background/Objectives: Persistent and distressing tinnitus and TMDs may significantly impair the quality of patients' lives. Problems are particularly severe for those who experience both. Although the exact causes of this association are not fully understood, several hypotheses connect TMD conditions with otological symptoms. Methods: The systematic review presented involved records published between 1 January 2004 and 27 November 2024, in the databases PubMed, Scopus, and Web of Science, according to the PRISMA guidelines. The search queries included "temporomandibular disorder" and "tinnitus". Inclusion and exclusion criteria were predefined according to PECOS. A risk of bias assessment and meta-analyses were performed. The study's protocol was registered in PROSPERO (CRD42024533293). Results: Eleven studies included in this review fulfilled all the predefined criteria. In a sample of 114,071 tinnitus patients, 50.99% (95% CI: 33.31-68.54) also had coexisting TMDs. Furthermore, tinnitus patients had more than 2.2 times higher odds of having TMDs compared to the control group (p = 0.002 for random effects). The absence of data regarding randomisation, blinding, and sample size justification was the most frequent risk of bias. Conclusions: Tinnitus frequently co-occurs in patients who suffer from TMDs. It is essential to expand the diagnostic evaluation of patients to confirm its presence and assess its impact on their quality of life. Additionally, dental consultation should be considered to evaluate patients about TMD signs and symptoms when suffering from tinnitus.