Efficacy of three rotary NiTi instruments in removing gutta-percha from root canals

Aim To investigate the ability of three rotary nickel–titanium instruments and hand instrumentation to remove gutta‐percha and sealer. Methodology Sixty freshly extracted human single‐rooted teeth, each with one root canal, were instrumented with K‐files and filled using cold lateral compaction of gutta‐percha and AH Plus (Dentsply Detrey, Konstanz, Germany) sealer. The teeth were randomly divided into four groups of 15 specimens each. Removal of gutta‐percha was performed with the following devices and techniques: ProTaper, R‐Endo, Mtwo and Hedström files. The specimens were rendered transparent and the area of remaining filling material on the root canal wall was measured using a computer image analysis program. Statistical analysis was accomplished by Kruskal–Wallis and Mann–Whitney U‐tests with Bonferroni correction for the analysis of residual root filling material and working time. Results The ProTaper group had less filling material inside the root canals than the other groups, but a significant difference was found between only the ProTaper and Mtwo groups (P