Cytotoxicity of endodontic instruments and materials on 3T3 fibroblasts

Objectives: This study evaluated and compared the long term cytotoxicity of iatrogenic perforation materials during root canal therapy on mouse 3T3 fibroblasts. Methods: The materials used in this study including two types of metal files (NiTi files, Stainless Steel files) and four types of retrograde filling materials (GIC, MTA, IRM, Super-EBA). Specimens were immersed in fetal bovine serum (FBS) and evaluated at the beginning, 2, and 4 weeks time periods. The cytotoxicity of all the specimens was detected by agar overlay cytotoxicity test. Results: No cytotoxicity effect was found in NiTi files, Stainless Steel files, and GIC from the beginning up to 4 weeks period. MTA, IRM, Super-EBA showed various cytotoxicity among the three detecting time points. By agar overlay cytotoxicity test, the mean values (cell lyses rate) of MTA were 5.32±0.44% for fresh samples, 2.54±1.92% for 2 weeks FBS immersion, and 3.01±1.85% for 4 weeks FBS immersion. For IRM, there were 36.39±2.71% for fresh samples, 97.08±1.83% for 2 weeks FBS immersion, and 54.01±5.92% for 4 weeks FBS immersion. For Super-EBA, there were 35.11±2.32% for fresh samples, 41.38±8.29% for 2 weeks FBS immersion, and 46.61±5.39% for 4 weeks FBS immersion. Conclusions: By the results of agar overlay cytotoxicity test, we conclude that, NiTi files, Stainless Steel files, and GIC which were immersed in FBS for 4 weeks revealed no cytotoxic effect to the mouse 3T3 fibroblasts. The cytotoxicity of IRM and Super-EBA was time dependent significantly with the FBS immersion up to 4 weeks period, whereas the cytotoxicity of MTA was diminished by time. Acknowledgement: This research was supported by the National Science Council of Taiwan (NSC 96-2815-C-039-040-B)