Effects of Blood Contamination on Sealing Ability and Microhardness of Mineral Trioxide Aggregate Used as a Root-end Filling Material

Purpose: The purpose of this study was to evaluate the influence of various contaminants on the apical sealing ability and microhardness of mineral trioxide aggregate (MTA) in extracted teeth ex vivo. Methods: The root canals of 51 single-rooted human teeth were prepared and filled with laterally condensed guttapercha cones and a sealer. After root surface coating, apicoectomy and preparation of apical cavities, the teeth were randomly divided into 5 groups. Group 1 was contaminated with distilled water (control) , group 2 with saline solution, group 3 with adrenalin solution, group 4 with blood, and group 5 with EDTA solution. After filling with MTA, the teeth were subjected to a leakage test. The teeth samples were then bisected and subjected to a microhardness test, and observed by stereoscopy and scanning electron microscopy. Results: A hermetic seal was observed morphologically in group 1. However, partial sealing and gaps between dentin and MTA or lacunae in MTA were observed in groups 2-5. Group 1 showed significantly less leakage than the other groups, but there was no significant difference among the experimental groups. The microhardness of group 5 was significantly less than that of group 1. Conclusion: The results suggested that contamination of MTA while setting decreased the sealing ability of MTA.