In vitro comparison of cyclic fatigue resistance of TruNatomy in single and double curvature canals compared with different nickel-titanium rotary instruments

Amr M Elnaghy,Ayman O Mandorah,Shaymaa E Elsaka

doi:10.1186/s12903-020-1027-7

Amr M Elnaghy, Ayman O Mandorah + Show 1 more

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https://doi.org/10.1186/s12903-020-1027-7

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Abstract

BackgroundThe purpose of this study was to compare the cyclic fatigue resistance of newly developed TruNatomy instruments (TRN) in single and double (S-shaped) curvature canals with HyFlex CM (HCM), Vortex Blue (VB) and RaCe (RC) instruments.MethodsSize 20/.04 taper and size 25/0.04 of HCM, VB and RC were used. For TRN instruments, size 20/.04 taper (small) and size 26/.04 taper (prime) were used. The instruments were tested in artificial canals with double curvature (coronal curve; 60° curvature, 5 mm radius and apical curve; 70° curvature and 2 mm radius) and single curvature (60° curvature, 5 mm radius). The number of cycles to failure (NCF) was recorded. Data were statistically analyzed by Kruskal-Wallis and Dunn’s multiple comparison tests. Weibull analysis was performed on NCF data. Statistical significant was set at p < 0.05.ResultsTRN and HCM revealed higher NCF compared with the other instruments for both tested sizes in single and double curvature canals (p < 0.05). TRN and HCM showed no statistically significant difference in the NCF (p > 0.05). The probability of survival was higher for HCM and TRN instruments than VB and RC instruments.ConclusionsHCM and TRN instruments were more resistant to cyclic fatigue than VB and RC instruments in single and double curvature canals. HCM and TRN instruments were anticipated to survive with higher number of cycles than the other tested instruments. RC instrument had the lowest fatigue resistance than the other instruments.

Highlights

The purpose of this study was to compare the cyclic fatigue resistance of newly developed TruNatomy instruments (TRN) in single and double (S-shaped) curvature canals with HyFlex controlled memory (CM) (HCM), Vortex Blue (VB) and RaCe (RC) instruments
TRN and HyFlex CM (HCM) revealed significantly higher number of cycles to failure (NCF) compared with the other instruments for both tested sizes in single and double curvature canals (p < 0.05)
TRN and HCM showed no significant difference in the NCF (p > 0.05)

Summary

Introduction

The purpose of this study was to compare the cyclic fatigue resistance of newly developed TruNatomy instruments (TRN) in single and double (S-shaped) curvature canals with HyFlex CM (HCM), Vortex Blue (VB) and RaCe (RC) instruments. It has been reported that alterations in the transformation behavior through heat treatment were effectual enhancing the flexibility and fatigue resistance of NiTi endodontic instruments [2, 5,6,7]. HyFlex CM instruments (HCM) (Coltène-Whaledent, Altstätten, Switzerland) are manufactured using a distinctive method to control material memory through a complex heating and cooling treatment [4]. It has been reported that this heat-treated alloy, together with the distinctive design characteristics of the instruments, enhances the flexibility of the instruments but without the shape memory of conventional superelastic forms of NiTi alloy [8,9,10]. The controlled memory (CM) NiTi instruments allow better maintenance of the original canal curvature and improved the efficacy of instruments in root canal treatment [9, 11]

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