In Vivo Host Interactions with Mineral Trioxide Aggregate and Calcium Hydroxide: Inflammatory Molecular Signaling Assessment

Introduction: Mineral trioxide aggregate (MTA) and calcium hydroxide [Ca(OH)(2)] are promising biomaterials for stimulating dentinogenesis and cementogenesis. This research was undertaken to understand how MTA and CA(OH)(2) participate in the inflammatory, healing, and biomineralization processes. In this part of the study, we evaluated inflammatory signaling molecules promoted by in vivo host interaction with MTA and Ca(OH)(2). Methods: Human dentin tubes were filled with Pro Root MTA (Dentsply Tulsa Dental, Tulsa, OK), Ca(OH)(2), or kept empty. After 12 hours and 1, 3, 7, 15, 30, and 60 days of implantation in subcutaneous tissues in the backs of mice, the tubes and surrounding tissues were retrieved for cytokine level quantification and histological and immunohistochemical analysis. Results: MTA and Ca(OH)(2) induced proinflammatory cytokine up-regulation for up to 3 days. Moreover, interleukin-10 overexpression was noted on the tissue in contact with the biomaterials during the acute phase of the inflammatory reaction. Immunohistochemical analyses showed an increased expression of myeloperoxidase, nuclear factor kappa B (NF-kappa B), cyclooxygenase-2, inducible nitric oxide synthase enzymes, and vascular endothelial growth factor on day 1 for all groups. Conclusions: MTA and Ca(OH)(2) increased the activation of the NF-kappa B signaling system on day 1 for all groups. This finding can be associated with a proinflammatory and pro-wound healing environment, which was promoted earlier by MTA. (J Endod 2011;37:1225-1235)