Comparative Evaluation of Citric Acid, Chlorhexidine, and Their Combination as Root Canal Irrigants on the Push-Out Bond Strength of Resin and Calcium Silicate-Based Sealers to Root Canal Dentin.

BACKGROUND: Root canal irrigants can alter root canal dentin and influence sealer adhesion. With increasing use of bioceramic sealers, understanding the effects of irrigants on bonding is essential for endodontic success. This in vitro study evaluated the effects of 1% chlorhexidine (CHX), 10% citric acid (CA), and their combination (CACHX) on the push-out bond strength (POBS) of AH Plus and BioRoot RCS to root canal dentin. METHODS: Eighty single-rooted premolars with a single canal were selected and divided into eight groups (n = 10) based on the final irrigation protocol: CA, CHX, CACHX, or distilled water. Root slices (2 mm) were obtained from the middle third. Groups A1-A4 were obturated with AH Plus and B1-B4 with BioRoot RCS. POBS was assessed using a universal testing machine, and failure modes were analyzed under a stereomicroscope. Normality was confirmed using the Shapiro-Wilk test. Intergroup comparisons were performed using independent t-tests, and intragroup comparisons were performed using one-way analysis of variance (ANOVA) with Tukey's post hoc test. RESULTS: The final irrigant significantly affected bond strength (p  < 0.001). AH Plus showed higher POBS than BioRoot RCS with CACHX (p = 0.008). BioRoot RCS exhibited the highest POBS with CA and the lowest with CHX (p  < 0.05). AH Plus showed the maximum bond strength with CHX, with no reduction when combined with CA (p  > 0.05). Cohesive failures predominated in AH Plus, whereas BioRoot RCS showed mixed failures. CONCLUSION: In this in vitro study, root canal irrigants significantly influenced sealer bond strength. AH Plus exhibited the highest bond strength with CHX, whereas BioRoot RCS performed best with CA. The combination of CA and CHX did not adversely affect AH Plus and may be considered a suitable irrigant protocol for this sealer.