In vitro comparison of the cyclic fatigue resistance of HyFlex EDM, One G, and ProGlider nickel titanium glide path instruments in single and double curvature canals

Abstract Background: 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. Methods: Size 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. Results: TRN 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. Conclusions: HCM 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.

Download Full-text

Effect of Cryogenic Treatment on Cyclic Fatigue of Nickel-titanium Rotary Files

10.21203/rs.3.rs-743019/v1 ◽

2021 ◽

Author(s):

Hamed Karkehabadi ◽

Abbas Farmani ◽

Zahra Pakseresht ◽

Faraz Sedaghat ◽

Saber Yavari Niya

Keyword(s):

Fatigue Resistance ◽

Room Temperature ◽

Cryogenic Treatment ◽

Cyclic Fatigue ◽

Nickel Titanium ◽

Warm Up ◽

Gutta Percha ◽

The Mean ◽

Time To Fracture

Abstract Objective: This study sought to assess the effect of cryogenic treatment on cyclic fatigue of Neoniti and Reciproc nickel-titanium (NiTi) rotary files. This in vitro, experimental study was performed on 48 Neoniti and Reciproc NiTi rotary files (#25, 6% taper) in two subgroups with and without cryogenic treatment. The files in cryogenic subgroups were stored in liquid nitrogen chamber at -196°C for 24 h. Next, they were placed at room temperature (25°C) to gradually warm up. Stainless steel (SS) blocks were used to standardize the degree of rotation of the files. The SS blocks simulated a root canal with the negative pattern of gutta-percha with 0.08 taper, #25 tip size, and 45° canal curvature. Each endodontic file was rotated in this canal until fracture. The time until fracture was recorded by a digital chronometer. Time to fracture was used to calculate the number of rotations before file fracture as the cyclic fatigue scale. Results: The mean cyclic fatigue resistance of both Neoniti and Reciproc rotary files in cryogenic subgroups was significantly higher than that in non-cryogenic control subgroups (P<0.05). Cryogenic treatment can significantly increase the cyclic fatigue resistance of Neoniti and Reciproc NiTi rotary files.

Download Full-text