Comparative evaluation of the effectiveness of different rotary systems in removal of root canal filling materials

Abstract

Aim: The aim of this study was to compare the remaining root canal filling materials after instrumentation using ProTaper Universal Retreatment (PTUR) system alone or combined with Neoniti, One Curve, and using hand Hedstrom files and Gates Glidden drills using cone beam computed tomography (CBCT) images. Methodology: Fifty-two mandibular premolars with single and straight canals were used. The canals were instrumented with ProTaper rotary instruments up to F3 and filled with gutta-percha and AH26 sealer. All the samples were placed into silicone models. Samples were scanned with CBCT and assigned into four groups (n=13): the PTUR system group, the PTUR system plus Neoniti group, the PTUR system plus One Curve group, and the hand Hedstrom files plus Gates Glidden group. The specimens were scanned once again after retreatment procedures, and the volume of the remaining filling materials was determined. Data were analyzed using Kruskal-Wallis and Dunn tests (a=0.05). Results: None of the retreatment procedures provided complete removal of the filling materials. Hedstrom files plus Gates Glidden removed more residual obturation materials than the other groups. The additional use of the Neoniti or One Curve systems significantly improved the removal of filling materials when compared with the PTUR system alone (P<0.05). The differences between the PTUR plus Neoniti group and the PTUR plus One Curve group were not statistically significant (P>0.05). Conclusions: Using Gates Glidden and Hedstrom files was the most effective way for retrieval of endodontic material from the root canals, while PTUR alone was the least effective method. Re-instrumenting with rotary files significantly improved the removal of root filling materials.