Comparative study of removal of current endodontic fillings

The aim of the present study was to assess the removability of canal fillings performed by using current methods during re-treatment with rotary instruments. Seventy-two freshly extracted human anterior teeth with single straight root canals were instrumented with Mtwo rotary files. The teeth were randomly divided into 4 obturation groups of 18 specimens each as follows: group 1, Resilon and Epiphany; group 2, GuttaFlow obturation system; group 3, EndoTwinn obturation system; group 4, gutta-percha with AH Plus sealer. The filled canals were re-treated by using Mtwo-Retreatment instruments and Mtwo instruments. The time required to remove the obturation material was recorded. After splitting the roots, the amount of residual filling material on the canal walls was imaged and measured with image analyzer software. Statistical analysis was accomplished by Kruskal-Wallis and Mann Whitney U tests for the analysis of root canal cleanliness. There was no statistically significant difference among the 4 filling techniques regarding the amount of residual material in the apical, middle, and coronal thirds and inside the whole canal area (P > .05). Regarding the mean time of re-treatment, the fillings performed by using GuttaFlow and EndoTwinn methods were removed much more quickly compared with the other 2 methods (P < .001). It was observed that the fillings performed with the above canal filling methods were removed in a similar fashion with rotary instruments during re-treatment.