Evaluation of Residual Root Canal Sealer Removal Efficacy of Different Irrigation Activation Techniques by Confocal Laser Microscopy Analysis

Objective: The purpose of this study was to use confocal laser microscopy analysis to evaluate the effectiveness of conventional needle irrigation (CNI), EndoActivator (EA), and EDDY during endodontic retreatment. Methods: This study included 45 maxillary incisor teeth with a single root and canal. Root canals were prepared with ProTaper Universal files (Dentsply Sirona, Ballaigues, Switzerland) and obturated with labeled sealer mixed with 0.1% Rhodamine B and gutta percha according to single cone techniques. Initial root canal filling material was removed using ProTaper Universal Retreatment files and F4 files. Teeth randomly were divided into 3 groups (n = 15) depending on the activation technique: CNI, EA (Dentsply, Tulsa Dental Specialties, Tulsa, OK), and EDDY (VDW, Munich, Germany). Confocal laser microscopy was used to evaluate the penetration area, depth, and percentage of the residual sealer in the apical, middle, and coronal sections after irrigation activation. Results: In all sections, the EDDY group had a lower penetration area of residual sealer than the CNI group (P< .05). In comparison to the coronal section, the penetration percentage of the CNI and EA groups was lower in the apical section (P< .05). In the CNI group, the penetration depth was higher at the coronal section than at the apical and middle sections (P< .05), and it was higher at the coronal section than at the apical section. Conclusion: Within the limitations of this study, none of the activation systems tested could completely remove the residual sealer. However, the lowest residual sealer was seen after using EA and EDDY.