Reduction of Somatic Tinnitus Severity is Mediated by Improvement of Temporomandibular Disorders

Successful orofacial treatment can reduce tinnitus severity in patients with somatic tinnitus (ST). However, it is still unclear to what extent the degree of reduction in temporomandibular disorders (TMD) actually contributes to the decrease in tinnitus severity after orofacial treatment. Therefore, the aim of this study was to analyze the mediating effect of reduction in TMD pain on the improvement of tinnitus severity after multidisciplinary orofacial treatment.A total of 80 patients with moderate to severe ST attributed to the temporomandibular region, were recruited from a tertiary tinnitus clinic. At baseline, patients were randomly assigned to the orofacial treatment group or to the control group. Both groups received a minimum of information and advice regarding their tinnitus complaints. The orofacial treatment group received orofacial physical therapy complemented with occlusal splints when needed, while the control group received no other treatment. A mediation analysis was performed according to the steps described by Baron and Kenny and the proportion of the mediating effect was calculated for the potential mediator: "change in TMD pain," measured by a one-point decrease in TMD pain screener score.Our analysis showed that 35% of the observed decrease in tinnitus severity can be attributed to a reduction in TMD pain. A significant total effect of orofacial treatment compared with control on the change in tinnitus functional index (TFI) score was found (B = 0.253 p = 0.025 Cl for B = 1.265-18.576). Orofacial treatment was also significantly related to the change in TMD pain (Exp (B) = 2.800, p = 0.034 Cl for Exp B 1.081-7.251). Additionally, the change in TMD pain screener score was significantly related to the change in TFI score (B = -0.273 p = 0.016 Cl for B = -19.875 to -2.119).Reduction of TMD pain is a mediating factor in the decrease of tinnitus severity after multidisciplinary orofacial treatment.Orofacial treatment can be used to decrease tinnitus severity in patients with TMD related somatic tinnitus.