TLR4 and pulpitis: In early pulpitis, when bacteria progress through the enamel and dentinal tubules and reach the pulp, DPCs can act as front-line troopers to detect bacterial lipopolysaccharide (LPS) via Toll-like receptor 4 (TLR4).28,29 Bacterial ligands bind to DPCs and activate intricate intracellular signaling pathways, which then produce a plethora of inflammatory cytokines and amplify the inflammatory response.10,29