Mineral trioxide aggregate induces the release of matrix metalloproteinase-9 by human neutrophils

Background/purposeAs a pulp capping agent, mineral trioxide aggregate (MTA) is commonly applied on inflamed tissues that present with a variety of immunocompetent cells, including neutrophils. Neutrophils are a major source of matrix metalloproteinases (MMPs) that have been implicated in the process of dentinogenesis. This study aimed to investigate the impact of MTA on human neutrophils.Materials and methodsFreshly purified human neutrophils were incubated with MTA or another commonly used filling material, intermediate restorative material (IRM). The viability and phagocytic activity of treated neutrophils were assessed by flow cytometry. In addition, the morphology of neutrophils was observed under scanning electron microscopy and the production of MMP-9 was analyzed by gelatin gel zymography.ResultsTreatment with MTA did not affect the viability, morphology, and phagocytic activity of neutrophils significantly. However, MTA increased the production of MMP-9 in neutrophils. However, IRM reduced the viability and altered cell morphology of the neutrophils.ConclusionMTA may participate in the pulpal inflammatory response by increasing MMP-9 production of neutrophils. These signals may facilitate the repair of dental pulp tissue.