Inflammatory response to calcium hydroxide based root canal sealers.

This study evaluated the inflammatory response to Sealapex, CRCS, Apexit, and Sealer 26 in the subcutaneous tissue and in peritoneal cavity of Balb/c mice. The inflammatory response of subcutaneous tissue was analyzed after 2, 4, 8, and 16 days. Intense neutrophilia was seen in response to all sealers during the initial periods. Differences among them related to the presence of necrosis and the number of inflammatory cells. In the intermediate phase marked differentiation of cells of the mononucleate phagocytic system into macrophages, epithelioid cells and multinucleate giant cells were observed with Sealapex. This response was less intense with CRCS and Apexit. Tissue necrosis was observed only at tissue sealer interfaces and only during the initial period with Sealapex but was seen throughout the experiment with all other sealers. The animals were injected in the peritoneal cavity with solutions containing the sealers and five mice from each group were killed 6 and 24 h, and 5 and 15 days later. During the initial periods (6 and 24 h) there was an intense migration of polymorphonuclear leukocytes to the peritoneal cavity in response to all sealers compared to the control. This migration was more intense for Sealer 26 and Apexit. An increase in mononucleate cell number was observed after 6 and 24 h and 5 days for all sealers and no differences were observed in relation to the control after 15 days.