Aim:
to explore whether changes in mandibular/condylar position are associated with alterations in brain activation in a patient with chronic subjective tinnitus and temporomandibular disorder (TMD) during a 3-month follow-up

Material and methods:
Single-patient case report (39-year-old; 2-year tinnitus; diagnosed TMD). TMJ magnetic resonance imaging (TMJ MRI) and functional magnetic resonance imaging(fMRI) of the brain were acquired in centric occlusion and after fabrication of an anterior repositioning appliance. fMRI was processed in FMRIB Software Library (FSL) (FEAT 6.0); Z-images were cluster-corrected with Z>3.1 and cluster-wise p<0.05 (Gaussian random field theory). Primary metrics: Activation Index (AI; Z-max), cluster size (voxels). Discriminative ability between states was explored with ROC analysis.

Case report:
Mean (AI) decreased from 5.51±0.67 (occlusion) to 5.05±0.70 (splint), p<0.05. A large cluster in the left superior temporal gyrus present in occlusion (AI=6.54; 16 799 voxels) disappeared with the splint. Regional reductions were also observed in anterior cingulate and prefrontal/insular cortices, while some right temporal/frontal clusters persisted with lower AI. Receiver Operating Characteristic (ROC) analysis suggested the AI (Z-max) had the highest discriminative ability between states (Area Under the Curve (AUC)≈0.69), whereas voxel-wise uncorrected/false discovery rate(FDR)-corrected p values were weak classifiers.

Summary:
In this clinical case, mandibular repositioning with an anterior repositioning appliance was associated with decreased cortical hyperactivation in auditory/affective regions and disappearance of a major left temporal cluster. Findings support a plausible somatosensory contribution to tinnitus modulation in TMJ disorder and motivate hypothesis-driven prospective studies. Causality cannot be inferred from a single-case design