Removal of Obturation Material from Root Canals Using a Combination of Reciprocal Instrumentation and Different Final Irrigation Techniques

Introduction: The predictability of successful non-surgical endodontic retreatment is directly related to it’s ability to completely cleanse and remove obturation material from the canal system. The purpose of this study was to evaluate the removal of gutta-percha from curved canals using three final irrigation methods: passive ultrasonic irrigation (PUI) with a 20/01 E1 insert (Irrisonic); XP-endo Finisher (XPF); and Easy Clean (EC). Methods and Materials: Forty mesial roots of mandibular molars with an angle of curvature between 10° and 20°, two canals, and independent foramina were cut into 16-mm sections. The canals were instrumented using the Reciproc system (R25) and filled with a #25 gutta-percha cone and AH-Plus sealer by the continuous-wave condensation technique. The roots were double-sealed with Coltosol and photopolymerizable resin and stored at 37°C and 100% humidity for 30 days. They were then randomized into 4 groups (n=10): control (C), PUI, XPF, and EC. All specimens were scanned using cone-beam computed tomography (CBCT), and fill volume data (in square pixels) were calculated before retreatment, after retreatment, and after final irrigation. The images were analyzed using Tps Dig software 2.32 by two blinded, calibrated examiners (intra-class correlation coefficient=0.9967). The results were analyzed in BioEstat 4.0. The nonparametric Kruskal-Wallis test with Dunn's post-hoc and Friedman comparison were applied. Significance was accepted at 5% (P<0.05). Results: None of the final irrigation protocols completely removed remnants of obturation material from the root canal systems (P>0.05). On comparative analysis with specimens divided into thirds, all methods were found to remove material equally, with no significant differences (P>0.05). Conclusion: Based on this in vitro study, the additional cleaning methods tested were equivalent to each other and did not lead to an improvement in the removal of residual obturation material.