Comparative Assessment of Push-Out Bond Strength and Dentinal Tubule Penetration of Different Calcium-Silicate-Based Endodontic Sealers

<b>Background:</b> Adhesion within endodontic obturation material and root canal walls improves the efficacy of the endodontic treatment by establishing a barrier that inhibits reinfection and entombs residual bacteria. This study evaluates the push-out bond strength (POBS) of calcium silicate sealers compared to an epoxy-resin-based sealer. <b>Methods:</b> A total of 36 extracted mono-radicular teeth were prepared with Pro Taper Ultimate and irrigated with 5.25% sodium hypochlorite and 17% EDTA. The specimens were randomly split into three groups (<i>n</i> = 12) according to the endodontic sealer and filling technique used as follows: Ah Plus with the continuous wave condensation technique (CWC), Ah Bioceramic (Ah Bio) with the single-cone technique, and Total Fill Hi-Flow (FKG Hi-Flow) with the CWC technique. The material was allowed to set for 4 weeks, and afterwards, the roots were placed in acrylic resin and sectioned into 1 mm transverse slices. A POBS test was conducted using a universal testing machine, and the mode of bond failure was assessed at 4× magnification using a stereomicroscope. Six specimens from each group were selected for SEM-EDX examination to evaluate dentinal tubule penetration. The data were analysed using analysis of variance and Tukey and Bonferroni post hoc tests. <b>Results:</b> The POBS tests revealed higher values for Ah Plus in comparison to both calcium silicate sealers (<i>p</i> < 0.001), while FKG Hi-Flow showed superior results to Ah Bio (<i>p</i> < 0.001). The cohesive mode of failure was prevalent in all three groups. <b>Conclusions:</b> In conclusion, the resin-based sealer showed higher bond strength and better dentinal tubule penetration than the two calcium silicate sealers tested, while FKG Hi-Flow outperformed AH Bio.