Microhardness and sealing ability of materials used for root canal perforations

Root perforations may lead to a loss of integrity in the root and periodontium, violations of the biologic periodontal distance, and injuries to periodontal tissue. This study sought to analyze the effect of root canal biomechanical preparation on the microhardness and the marginal sealing ability of different materials used to treat root perforations. Standard root perforations were performed in 96 bovine incisors. The teeth were divided into four groups (n = 24), based on the material used to treat those teeth: Mineral trioxide aggregate (MTA) (Group 1), MTA protected with cyanoacrylate (Group 2), MTA protected with glass ionomer (GI) cement (Group 3), and castor oil bean (COB) cement (Group 4). After root perforations were closed, the root canals were prepared biomechanically and teeth were sectioned longitudinally. Microleakage and microhardness of sealed perforations were assessed; microleakage data were submitted to analysis of variance (ANOVA) testing, while microhardness data were submitted to Dunnet and Tukey tests (p < 0.05). Group 4 reported the lowest amount of microleakage (0.65 mm), followed by Group 3 (1.02 mm), Group 1 (1.14 mm), and Group 2 (1.30 mm); however, no difference was detected among the groups. Groups 1-3 demonstrated significantly higher microhardness values compared to COB. It was concluded that the chemical and mechanical agents used during root canal preparation did not affect the sealing procedures. Administering surface protection to MTA did not improve microhardness or sealing.