IL1B and pulpitis: IHC analysis revealed that the mean optical density (MOD) values for IL-1β were consistently lower in the laser group at all four time points (p < 0.05), while the MOD values for Par3 were consistently higher in the laser group (p < 0.05).<h4>Conclusion</h4>The Er:YAG laser used during pulpotomy in mature permanent rat teeth with pulpitis preserves the remaining healthy pulp tissue, reduces IL-1β expression, and enhances Par3 expression, thereby alleviating inflammation and promoting tissue repair.