Influence of ultrasonic activation over final irrigants in the removal of photosensitizer from root canal walls after photodynamic therapy

Introduction: The aim of the present study was to evaluate the influence of ultrasonic activation (US) of the final irrigant in the removal of the photosensitizer from root canal walls after photodynamic therapy. Methods: The root canals of 60 single-rooted bovine extracted teeth were filled with 0.01% methylene blue and submitted to photodynamic therapy for 90 s. After that, the roots were divided into six groups (n = 10) according to the final irrigation protocol: distilled water (DW), DW + US, 17% EDTA, QMix, EDTA + US, and QMix + US. Then, the samples were submitted to scanning electron microscopy where a scoring system was used to evaluate the images and effectiveness of proposed treatments in the cervical, middle and apical regions of the root canals. The data were statistically analyzed by the Kruskal-Wallis and Mann Whitney U tests for intergroup comparisons as well as the Wilcoxon and Friedman tests for intragroup comparisons at 5% of significance. Results: The 17% EDTA + US and QMix + US treatments were most effective in the removal of the photo sensitizer in all regions of the root canal; the difference was statistically significant when compared to all other groups (p<0.05). There were no significant differences in the intragroup analysis comparing the effectiveness in the different regions of the same group (p<0.05). Conclusions: US can aid 17% EDTA and QMix in removing the photosensitizer after photodynamic therapy and contributes to cleaning root canal walls. (C) 2017 Elsevier B.V. All rights reserved.