The effect of RISA on push out bond strength of an epoxy resin sealer and a bioceramic sealer: an in vitro study

Abstract

Abstract This study aimed to evaluate the effect of Reduced Ionic Strength Agent (RISA), used as a final irrigant, on the push-out bond strength of resin-based and bioceramic root canal sealers compared with ethylenediaminetetraacetic acid (EDTA). Sixty extracted single-rooted mandibular premolars were prepared using Reciproc R40 instruments and randomly assigned to four groups according to the final irrigation protocol and sealer type: EDTA–resin, EDTA–bioceramic, RISA–resin, and RISA–bioceramic. After obturation using the single-cone technique, one 1-mm-thick slice was obtained from the middle third of each root. Push-out bond strength was measured using a universal testing machine. Data were analyzed using two-way analysis of variance and Bonferroni-adjusted post hoc tests. Failure modes were assessed under a stereomicroscope and compared using the chi-square test. The RISA–bioceramic group exhibited the highest mean push-out bond strength, whereas the EDTA–resin group showed the lowest mean value. Two-way ANOVA revealed significant main effects of both final irrigant and sealer type on push-out bond strength ( p  < 0.001). Overall, RISA resulted in higher bond strength values than EDTA, and the tested bioceramic sealer exhibited higher bond strength than the tested epoxy resin-based sealer. No significant interaction was observed between irrigation protocol and sealer type. Failure mode distributions were predominantly mixed and did not differ significantly among the groups. Within the limitations of this in vitro study, RISA resulted in higher overall push-out bond strength than EDTA. Although these findings suggest that RISA may have the potential to enhance sealer adhesion, further studies incorporating aging protocols and clinically relevant experimental conditions are needed to determine the long-term durability and clinical relevance of the observed bond-strength advantage.