Glide path effect on Direct R Gold’s mechanical performance and ability to reach full working length: an ex vivo study

Abstract

Objective: To inquire the effect of glide-path (GP) preparation on reaching the working length and its influence on the cyclic fatigue and torsional stress of new Direct R MI gold files.
Methods: A total of eighty Direct R MI gold files were split into two groups (n=40) according to the establishment of the GP: the GP group with the GP performed with #8, #10, and #15 K hand files, and the Without GP group (WGPG). The files from each group were randomly divided into two subgroups (n=20). Subgroups of each group were subjected to cyclic fatigue tests at a curvature of 90° angle and a 5 mm radius along with a torsional resistance test (torque to fracture [TtF]) through a static torsional test device by blocking the file at 3 mm from the tip. The time to fracture (TF), number of cycles to failure, fractured tip length segments for both cyclic and torsional tests, and TtF were recorded. One-way analysis of variance, and Tukey’s multiple comparison tests were performed, with the significance level set at 0.05.
Results: All the instruments reached working length. There were no statistically significant differences between subgroups of GP and WGPG in terms of TF, number of cycles to failure, TtF, or fractured tip length (P > 0.05). Deformations were observed in only one file in the WGPG.
Conclusion: The creation of a GP did not impact the cyclic fatigue or torsional resistance of Direct R gold files. The novel reciprocating single-file system achieved full working length in all cases, even without a prior GP