In vivo comparison of the biocompatibility of two root canal sealers implanted into the subcutaneous connective tissue of rats.

The purpose of this study was to evaluate the in vivo biocompatibility of Apexit (a calcium hydroxide) and Pulp Canal Sealer (a classic zinc oxide-eugenol), root canal sealers, after implantation in rat connective tissue. Forty-four white female Wistar-Furth rats were used. Each sealer was placed in Teflon tubes and implanted into specific dorsal subdermal tissues sites. Implants were removed after 5, 15, 60, and 120 days; fixed; and histologically prepared for microscopical evaluation. Severe inflammatory reactions with differing extensions of necrosis were observed with Apexit on the 5th and 15th days. The intensity of the reaction had diminished by the 60th day, and this reduction continued progressively through the 120th day. It was characterized by the presence of connective tissue with a few macrophages. Moderate to severe inflammation with confined areas of necrosis was observed in the Pulp Canal Sealer specimens on the 5th day. The intensity of the reaction diminished by the 15th, 60th, and 120th days, but remained slightly greater than Apexit through longterm observation periods.