Smear layer removal efficacy of various irrigation solutions with an ultrasonic activation system: an in vitro study

Purpose: In this in vitro study, the smear layer removal efficiency of 17% ethylenediaminetetraacetic acid (EDTA), 10% glycolic acid (GA), and 18% etidronic acid, 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) solutions was evaluated.
Methods: A total of 80 human mandibular premolar teeth were used in the study. The teeth were prepared using the Reciproc R25 rotary instrument system. A total of 10 mL of 2.5% NaOCl irrigation solution was used: 5 mL during the procedure and 5 mL after it. The teeth were divided into four groups (n = 20): group 1, 17% EDTA + passive ultrasonic activation (PUI); group 2, 10% GA+PUI; group 3, 18% HEBP + PUI; and group 4 (control group), distilled water + PUI. Based on the central parts of the coronal, middle, and apical thirds images were taken under a low vacuum scanning electron microscopy at 2000× magnification. The presence of smear layer in the coronal, middle, and apical thirds was evaluated using a five-score evaluation system. Data were analyzed with Kruskal–Wallis and Dunn tests.
Results: No statistically significant difference was found among the groups 1, 2, and 3 in all regions (p>0.05).
Conclusion: EDTA, GA, and HEBP irrigation did not affect the smear layer removal by PUI.