ABSTRACT
The materials used for obturation of root canal system may be extruded through apical foramen into the periapical tissue. Therefore, biocompatibility of these materials is very important. The purpose of this study was to evaluate the in vivo biocompatibility of three conventional endodontic sealers: AH26, Roth 801, and ZOE after their subcutaneous implantation in rats. Twenty-two mature male Albino rats, weighting from 250 to 500gr were used. Each animal received four polyethylene implants; three implants were containing test sealers and one was empty tube as negative control. The animals were sacrificed at third day and third month after implantation and the implants were dissected with 2cm of surrounding tissue margins. Then, tissue reactions to the test materials were evaluated histologically and quantitatively by a pathologist under light microscope, after histologic processing and staining with H-E. The obtained results were analyzed statistically by Mann-Whitney test. After 3 days, tissue reaction to ZOE was more acute than AH26, Roth 801, and control group. But after 3 months, no significant difference was observed among these three sealers and among those and control group. According to this study, all of the sealers cause inflammatory reactions immediately after contact with tissue, but the intensity of these responses decrease with time. The acute responses of third day changed to chronic, proliferative, healing processes in third month