Bond strength evaluation of endodontic sealers with different rinsing protocols

Objectives: The aim of this study was to examine the influence of different cleaning and disinfecting rinsing solutions on the bond strength of two endodontic sealers. Methods: 70 human incisivi were randomly assigned to seven groups (n=10) in an in-vitro study. The teeth were decapitated 2mm above the dentino-enamel junction and root canal treatment was performed. Rinsing during the root canal treatment was carried out using 5% NaOCl solution (group 1) or a consecutive use of the following rinsing solutions: 5% NaOCl+17% EDTA (group 2), 5% NaOCl+2% CHX (group 3), 5% NaOCl+20% citric acid (group 4), 5% NaOCl+20% citric acid+2% CHX (group 5), 5% NaOCl+17% EDTA+2% CHX (group 6). 0.9% saline solution (group 7) served as control. In each group, five teeth were obturated by lateral condensation using AH-Plus® (AH), and five teeth by using a single cone technique with resin-coated guttapercha and EndoREZ® (ER). 2mm thick root-disks were cut from the apical section. Performing a push-out test, the bond strength of the different sealers was determined at a universal test bench. For statistical analysis, one-way-ANOVA was applied at a significance level of 95%. Results: In five out of seven examined rinsing groups lateral condensed guttapercha with AH reached higher bond strengths than the adhesively processed guttapercha of the ER-system (p<0.05)*: mean force (N±SD) AH vs. ER: group (1)*:8.48±0.60 vs. 0.08±0.00; group (2):6.98±2.14 vs. 3.17± 2.88; group (3)*: 8.40±0.07 vs. 3.37±2.64; group (4)*:7.90±1.88 vs. 0.30± 0.10; group (5)*:8.37±0.43 vs. 0.50±0.20; group (6)*:8.13±0.07 vs. 3.10± 3.90; group (7): 8.14±0.07 vs. 5.10±3.59. No significant differences were found with respect to the rinsing protocol. Conclusions: In this in vitro-study, different rinsing protocols had no effect on the bond strength of AH and ER as endodontic sealers.