Comparative tissue toxicity evaluation of four endodontic sealers.

The tissue toxicity of zinc oxide-eugenol, Tubli seal, Sealapex, and Endoflas F.S. was investigated by injecting them into the subcutaneous connective tissue of the dorsal surface of rats and studying the tissue response histologically. Animals were killed after time intervals of 48 h, 7 days, 14 days, 1 month, and 3 months; tissue sections were taken from the injection sites. Histological examination of the tissue sections revealed that all of the sealers caused some inflammation that decreased with time, except in the case of zinc oxide-eugenol where it increased from the 48th hour to the 7th day and after that showed a decreasing trend. Overall, Sealapex showed the least inflammatory reaction compared with other sealers used, because it showed moderate inflammation at 48 h that became mild in later periods. Zinc oxide-eugenol, Tubli seal, and Endoflas F.S. were severely toxic at 48 h and 7 days. This toxicity decreased gradually in later time periods. No inflammatory reaction was seen at 3 months with any of the sealers used.