A Comparison Of The Cyclic Fatigue Resistance Of Various File Systems Following Sterilization Or Immersion In Sodium Hypochlorite
Purpose: The aim of this study was to evaluate the impacts of cyclic fatigue resistance of four heat-treated nickel-titanium (NiTi) rotary instruments after immersion and sterilization in sodium hypochlorite (NaOCl).
Materials and Procedures: In simulated canals, the cyclic fatigue resistance of 320 new nickel-titanium endodontic files was examined. A total of four subgroups (n = 20) of 25/.06 TruNatomy (TN; Dentsply Sirona, Maillefer, Ballaigues, Switzerland), 25/.06 Hyflex CM (Coltene Whaledent, Cuyahoga Falls, OH), 25/.06 Hyflex EDM (Coltene, Whaledent Pvt Ltd), and 25/.06 EdgeFile X3 (EdgeEndo, Albuquerque, NM, USA) files were created for The new instruments in Subgroup 1 (the control group) were not autoclave sterilized or submerged in NaOCl. Instruments in subgroup 2 were dynamically submerged in 5.25% NaOCl solution for 3 minutes. Instruments in subgroup 3 received three rounds of autoclave sterilization at 121°C with 15 pressure for fifteen minutes. Subgroup 4 enlisted instruments that underwent three cycles of autoclave sterilization and a round of dynamic immersion in NaOCl solution. Every file was rotated until a crack developed. ANOVA with the post-hoc Games Howell test was used to compute and statistically assess the means and standard deviations of the number of cycles to failure (NCF). (P < .001).
Results: A statistically significant difference in NCF was found when the four instruments under investigation were compared (P >.001). In all the subgroups, EdgeFile X3 files demonstrated the highest cycle fatigue resistance, followed by Hyflex EDM files, Hyflex CM files, and TruNatomy with the lowest resistance. When comparing the instruments with regard to the four treatment procedures, there was also a statistically significant difference (P<.001) (subgroups). The cyclic fatigue of the NiTi files tested was affected by the instruments' dynamic immersion in NaOCl solution for three minutes, followed by three cycles of autoclave sterilization. All four of the heat-treated instruments significantly outperformed the control group in terms of cyclic fatigue resistance.
Conclusions: Within the constraints of this study, the EdgeFile X3 group, Hyflex EDM group, Hyflex CM group, and TruNatomy group had the strongest fracture resistance to cyclic fatigue. Instruments that underwent three minutes of dynamic immersion in NaOCl solution followed by three cycles of autoclave sterilization had an impact.