AimTo 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.MethodologyThirty 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%.ResultsNone 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).ConclusionsThe 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.

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Background: This study aimed to evaluate the effectiveness of passive ultrasonic irrigation (PUI) compared to mechanical activation with Easy Clean in the removal of organic tissue from simulated areas of internal root resorption.Methods: The root canals of 72 extracted single-rooted teeth with oval canals were instrumented with Reciproc R25 instruments. After root canal preparations, the specimens were split longitudinally, and semicircular cavities were prepared using a round bur on each half of the roots. Samples obtained from bovine muscle tissue were weighed and adapted into semicircular cavities. The roots were reassembled and joined, and the teeth were divided into six groups (n=12) according to the irrigation protocol: NaOCl without activation; NaOCl + PUI; NaOCl + Easy Clean; distilled water without activation; distilled water + PUI; and distilled water + Easy Clean. After irrigation protocols, the teeth were disassembled, and the remaining organic tissue was weighed. Data were analyzed by two-way ANOVA and Tukey’s post hoc test (p<0.05).Results: Tissue weight reduction was significantly affected by the activation method (p<0.05) and by irrigation solution (p>0.05). The use of Easy Clean resulted in the greatest tissue weight loss compared to those of PUI and no activation (p<0.05).Conclusions: Mechanical activation with Easy Clean enhanced organic tissue removal from simulated internal resorption more effectively than passive ultrasonic irrigation. Easy Clean for agitation of the irrigating solution is effective in removing simulated organic tissues from artificial internal resorption cavities, being an alternative to the use of passive ultrasonic irrigation