Related Experiment Video
Updated: Jun 4, 2026

Scanning Electron Microscopic Evaluation of Surface Defects of Remover Retreatment File After Single and Multiple Uses
Published on: October 11, 2024
Comparison of debris extruded apically and working time used by ProTaper Universal rotary and ProTaper retreatment
Mary Kinue Nakamune Uezu1, Maria Leticia Borges Britto, Cleber K Nabeshima
1University Cruzeiro do Sul, São Paulo, SP, Brazil.
Objective:
The aim of this study was to evaluate the in vitro action of ProTaper retreatment files and ProTaper Universal in the retreatment of mandibular premolars.
Material And Methods:
The amount of debris extruded apically was measured and the time to reach the working length and to complete the removal of gutta-percha was observed. Thirty teeth had their canals prepared using ProTaper Universal files and were obturated by the single cone technique. The teeth were then stored at 37ºC in a humid environment for 7 days. During the use of the rotary instruments for root canal filling removal, the apical portions of the teeth were attached to the open end of a resin tube to collect the apically extruded debris.
Results:
ProTaper Universal files were significantly faster (p=0.0011) than the ProTaper retreatment files to perform gutta-percha removal, but no significant difference was found between the files regarding the time to reach the working length or the amount of apical extrusion.
Conclusions:
ProTaper Universal rotary had better results for endodontic retreatment, and both techniques promote similar apical extrusion of debris.

