(PR134) Proteomic Analysis of Pulpal Fluid Biomarkers in Reversible and Irreversible Pulpitis: A Diagnostic Study

Introduction: Pulp fluid, the interstitial fluid surrounding pulpal cells in the sub-dentin space, varies in volume and molecular composition with vasodilation and changes in pulpal tissue permeability. Our lab previously demonstrated that pulp fluid collected from extracted human teeth has potential as a diagnostic tool to distinguish between normal, reversible pulpitis (RP), and irreversible pulpitis (IP), particularly through the varying expression of TIMP-1 and TIMP-2. The objective of this study is to identify and quantify pulpal fluid proteins from normal and diseased pulp.

Methods: Pulp fluid was collected from patients undergoing endodontic treatment at the Post-Graduate Endodontics Clinic at the UCLA School of Dentistry. Teeth clinically diagnosed as normal (control), RP, and IP were included (n=5 per group). Exclusion criteria included prior endodontic treatment, resorption, and trauma. Samples were collected by minimally manipulating the pulp chamber and extracted pulp fluid with 0.1-20 µL Eppendorf tips. Proteomic analysis was performed using an antibody array and confirmed the result with ELISA. Sensitivity and specificity were analyzed using ROC curve analysis.

Results: Protein expression in the pulp fluid of teeth with normal pulp, RP, and IP were different with a higher expression of inflammatory molecules in the IP group (IL-6, IL-8, TIMPs) as compared to RP and normal pulp.

Conclusion: The expression of pulp fluid inflammatory molecules was higher in teeth with IP than in RP and normal pulp. Future studies of larger sample size are needed for definitive validation of pulp fluid proteins and potential use as a chair-side diagnostic test.