(PO67) Torsional Fatigue of the SS White DCTaper Size 25 Rotary File Compared to the Dentsply Sirona TruNatomy Prime Shaper Rotary File

Abstract: Separated files that can neither be removed nor bypassed may decrease the success of endodontic treatment outcomes. If rotary files separate, torsional fatigue is commonly the cause. In endodontics, torsional fatigue can occur when the tip of a rotary file binds in the canal while the motor continues to rotate, causing instrument separation. The aim of this study was to evaluate torsional fatigue of the DCTaper file (size 25v06) versus the TruNatomy Prime Shaper file (size 26v04) by comparing time to separation (TTS). Sixty-four torsional fatigue simulations were performed for both DCTaper and TruNatomy files, utilizing a vise to simulate tip lock. Files were secured in the vise 3 mm from the tip while a rotary handpiece rotated the file at 40 RPM. Time to separation for each group was recorded, averaged, and analyzed using SPSS version 25.0 (IBM SPSS Statistics, v25; IBM Corp). The mean TTS for the DCTaper and TruNatomy Prime Shaper files was 3.65 s (SD = 0.55) and 3.12 s (SD = 0.40), respectively. A significant difference was noted between the mean TTS of the two file types, p < .001. The DCTaper file had a significantly higher torsional fatigue resistance than the TruNatomy Prime Shaper file. The endodontic provider should consider establishing a glide path to reduce the probability of torsional fatigue when using either file system.