Bleaching agents may affect surface properties of mineral trioxide aggregate (MTA) as a coronal barrier. The purpose of this study was to investigate surface properties of MTA after exposure to intracoronal bleaching agents. MTA was set in acrylic molds with a 4 mm high central hole and a 6 mm diameter. Specimens were divided into four groups (n = 10); three groups were exposed to bleaching agents three times on every fourth day (carbamide peroxide—CP, hydrogen peroxide—HP, sodium perborate—SP) and a control group—C. The surface roughness and Vickers surface microhardness were measured. Differences between groups were analyzed using a Kruskal–Wallis test and intergroup comparisons were assessed with a Mann–Whitney U test with a Bonferroni correction (p < 0.0001). The microstructure and elemental composition were observed using a scanning electron microscope (SEM) and an energy-dispersive X-ray microanalysis (EDX) system. In terms of microhardness, the decrease in the HP group was significantly greater than that of the CP and SP groups; CP group significantly greater than that of the SP group, however, there was no significant difference between the SP and C groups. Surface roughness values were compared between groups, and no significant differences were observed between the CP and HP groups, and they exhibited significantly higher roughness values than the SP and C groups. SEM/EDX showed that the bleaching agents affected the elemental distribution. Bleaching agents adversely affected the surface roughness, surface microhardness and elemental distribution of MTA, with exposure to SP causing fewer changes on the surface properties than CP or HP.
Intracoronal bleaching agents Mineral trioxide aggregate Intracoronal barrier Microstructure Microhardness
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The author would like to thank Karadeniz Technical University, Faculty of Engineering Mettallurgical and Materials Engineering for the SEM/EDX analysis.
The study was self-funded.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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