Cellular and Mechanical Responses to Zinc Polycarboxylate Cement Modified With 5% or 10% Potassium Nitrate: An In Vitro Study

This study investigated the biological response of human peripheral blood mononuclear cells (PBMCs) to zinc polycarboxylate (ZP) cement modified with 5% or 10% potassium nitrate (KNO₃) and assessed its mechanical properties. Discs of unmodified ZP, ZP + 5% KNO₃, ZP + 10% KNO₃, or mineral trioxide aggregate (MTA) were indirectly exposed to PBMCs using a transwell system. Cells were incubated with or without lipopolysaccharide (LPS) stimulation. Cytotoxicity (LDH release), viability, IL-6 and TGF-β secretion were evaluated. Material pH, ion release, compressive strength and microhardness were also assessed. ZP + 5% KNO₃ significantly reduced LDH and IL-6 levels and increased TGF-β release compared to ZP alone. Mechanical strength was maintained in ZP + 5% KNO₃ but decreased at 10% KNO₃. MTA showed lower strength but higher cell viability. ZP + 5% KNO₃ demonstrated a balanced profile of immunomodulation, regenerative signalling and mechanical integrity, supporting its potential use in vital pulp therapy. Further in vivo investigations are recommended.