Influence of the final irrigation solution on the push-out bond strength of calcium silicate-based, epoxy resin-based and silicone-based endodontic sealers

The aim was to evaluate the influence of different irrigation solutions on the push-out bond strength (POBS) of three different sealers (AH Plus, BioRoot RCS, GuttaFlow2). Root canals of 180 single-rooted human teeth were instrumented with F360 up to size 45.04. All canals were irrigated with 5 ml NaOCl 3% and 5 ml EDTA 17%. The canals were finally irrigated with either 5 ml NaOCl 3%, CHX 2%, EDTA 17%, citric acid 20% or NaCl 0.9% (n = 36) with a contact time of 5 min and obturated using matching gutta-percha cones according to the single-cone technique in combination with one of the sealers (n = 12). After 8 weeks of incubation, the roots were embedded in resin. Two slices of 1 mm thickness were obtained representing the middle third of the root. Dislodgement resistance was measured and POBS was calculated. Specimens were examined under 4× magnification to determine the mode of bond failure. Statistical analysis was performed using two-way ANOVA and Student–Newman–Keuls test for POBS and Chi-square test for the mode of failure. POBS was significantly affected by the factor “sealer” (P < 0.001) and by the interaction “sealer/irrigation solution” (P < 0.01). AH Plus revealed significantly higher POBS than BioRoot RCS and GuttaFlow2 (P < 0.05). The POBS of GutttaFlow2 was not affected by the irrigation protocol (P > 0.05). The POBS of AH Plus was positively influenced by EDTA and NaOCl. EDTA had a negative effect on the POBS of BioRoot RCS. The POBS of GuttaFlow2 was not influenced by the irrigation solutions.