Related Experiment Video
Updated: Mar 8, 2026
Scanning Electron Microscopic Evaluation of Surface Defects of Remover Retreatment File After Single and Multiple Uses
Published on: October 11, 2024
Less extrusion debris during the retreatment of curved canals using twisted files with higher rotational speeds: an
Mengdong Liu1,2, Shijiang Xiong3, Fei Tan2
1School of Dentistry, Shandong University, 44, Wenhua West Road, Jinan, 250012, Shandong Province, China.
Background:
Debris extrusion from the apical foramen can be problematic in severely curved canals. This study aimed to assess the use of Twisted Files (TF) at different rotational speeds during retreatment, compared with manual technique using Triple-Flex Files (TFF).
Methods:
Forty-eight mesiobuccal root canals were randomized to four groups (n = 12 per group). In groups A, B, and C, gutta-percha was removed using TF at 500, 1000, and 1500 rpm, respectively, while it was removed using TFF in group D. Apical debris was collected in a pre-weighed centrifuge tube. The weight of dry debris was assessed by comparing the pre- and post-instrumentation weight for each group.
Results:
Instrumentation in group D (0.69 ± 0.04 mg) extruded significantly more debris than any of the TF groups (A: 0.54 ± 0.05 mg; B: 0.48 ± 0.04 mg; C: 0.42 ± 0.03 mg; all P < 0.001). In addition, increasing the rotational speed of TF decreased the amount of extruded debris (A vs. B: P = 0.006; B vs. C: P < 0.001; A vs. C: P < 0.001).
Conclusions:
TF at 1500 rpm produced less apical extrusion debris than other TF operating speeds and TFF.
