Hamed Karkehabadi - Assistant Professor, Department of Endodontics, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran
Shahriar Shahriari - Assistant Professor, Department of Endodontics, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran
Faraz Sedaghat - Assistant Professor, Department of Endodontics, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran
Ebrahim Yarmohammadi - Department of Operative Dentistry, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran
Hadiseh Abbaspourrokni - Department of Endodontics, Dental School, Hamadan University of Medical Sciences, Hamadan, Iran- Assistant Professor, Department of Endodontics, Faculty of Dentistry, Mazandaran University of Medical Sciences, Sari, Iran

Background: This study aimed to assess the effects of calcium hydroxide, Biodentine, calcium-enriched mixture (CEM) cement, and mineral trioxide aggregate (MTA) on root dentin flexural strength after a ۳۰-day exposure period.Methods: This in vitro experimental study evaluated ۲۵ freshly extracted sound human incisors with no caries or restorations. The apical ۵ mm and the coronal two-thirds of the crowns were cut such that all samples had ۱۰ mm length. Dentin samples (n=۲۰ in each group) were then exposed to ۲ mm thickness of calcium hydroxide, Biodentine, CEM cement, MTA, or saline (control) in petri dishes for ۳۰ days. Finally, dentin samples were subjected to a three-point bending test after the intervention, and the flexural strength data were analyzed using one-way ANOVA, Tukey’s test, and t test.Results: Thirty-day exposure to all four biomaterials decreased the flexural strength of root dentin (P < ۰.۰۵). The four groups were significantly different in terms of the flexural strength of root dentin (P = ۰.۰۰۱). The flexural strength of root dentin was significantly lower following exposure to calcium hydroxide (P = ۰.۰۰۳), Biodentine (P = ۰.۰۱۱), CEM cement (P = ۰.۰۰۱), and MTA (P = ۰.۰۰۷) compared to saline. The reduction in strength following exposure to calcium hydroxide was higher than that in Biodentine, CEM cement, and MTA groups (P < ۰.۰۵) while the latter three were not significantly different in this respect (P > ۰.۰۵).Conclusions: In general, all four tested biomaterials decrease the dentin strength although this reduction is more prominent by calcium hydroxide.

Root canal filling materials, Mineral trioxide aggregate, Biodentine, CEM cement, Calcium hydroxide, Dentin, Flexural strength