38 Salivary DNA methylation signatures as potential biomarkers for chronic painful temporomandibular disorders: A pilot study

Objectives/Goals: To evaluate the feasibility of developing salivary DNA methylation-based biomarkers for objective diagnosis and stratification of Temporomandibular Disorders (TMD), addressing the critical need for quantitative diagnostic tools to complement current subjective assessments and clinical examinations. Methods/Study Population: This cross-sectional pilot study enrolled 13 TMD patients and 4 pain-free controls from the University of Minnesota TMD Orofacial Pain Clinic. Participants underwent comprehensive DC/TMD diagnostic evaluation and completed validated instruments measuring pain intensity (VAS), psychological status (PHQ-9, PCS), and functional impairment (GCPS). Saliva samples were analyzed using Illumina EPIC BeadChip arrays interrogating ~850,000 CpG sites. Bioinformatic analyses included principal component analysis, identification of differentially methylated sites, and development of composite Methylation Profile Scores for patient stratification Results/Anticipated Results: Principal component analysis showed clear clustering separation between TMD patients and controls. Methylation profile scores demonstrated clear stratification between controls, high-impact, and low-impact TMD subgroups. High-impact TMD participants (n=6) showed significantly elevated clinical severity scores compared to low-impact TMD (n=7): pain intensity (52.0±11.3 vs 25.0±13.8), depression (20.5±7.3 vs 8.4±4.9), and catastrophizing (12.6±8.1 vs 6.4±6.5). Promoter-level analysis identified candidate genes associated with TMD severity phenotypes, supporting the potential for epigenetic biomarkers to enable objective patient stratification and guide precision treatment selection. Discussion/Significance of Impact: Epigenetic biomarkers capturing TMD heterogeneity could transform clinical practice by enabling early-risk stratification, preventing progression to high-impact chronic pain through personalized interventions, and reducing the substantial healthcare burden of this prevalent orofacial pain condition.