The influence of the addition of surfactants to sodium hypochlorite on the removal of hard tissue debris.

AIM: To evaluate the effect of the addition of surfactants to sodium hypochlorite (NaOCl) on the removal of accumulated hard tissue debris (AHTD), before and after final irrigation with 17% EDTA, from mesial canals of mandibular molars through microcomputed tomographic (micro-CT) analysis. METHODOLOGY: Thirty moderately curved mandibular mesial roots with Vertucci type II canal configuration were selected and scanned in a micro-CT device at an isotropic resolution of 22.9 µm. The specimens were assigned to three groups (n = 10) with respect to the root length, degree of curvature of the mesial root, volume and 3D anatomy of the root canals according to the irrigating solution used during root canal preparation: 2.5% NaOCl and 0.1% Benzalkonium Chloride, 2.5% NaOCl and 0.1% Tween 80 and 2.5% NaOCl without additives. The root canals were instrumented up to Reciproc R25 instrument. Then, the specimens were scanned again after canal preparation and after final irrigation with 17% EDTA, and the registered data sets were examined to evaluate the percentage of AHTD. For comparison between the different groups before and after using 17% EDTA, the Kruskal-Wallis test was used with a significance level of 5%. For comparison between the same groups before and after using 17% EDTA, the Wilcoxon test was used with a significance level of 5%. RESULTS: None of the irrigant solutions tested was able to completely eliminate hard tissue debris from mesial canals of mandibular molars. There were no significant differences in the percentage of AHTD amongst the different irrigation solutions (P > 0.05). Final irrigation with 17% EDTA significantly reduced the percentage of AHTD (P < 0.05), without differences amongst the groups (P > 0.05). CONCLUSIONS: The addition of surfactants to NaOCl did not affect the removal of AHTD from mesial canals of extracted mandibular molars. Final irrigation with 17% EDTA significantly improved AHTD removal.