Comparison of mechanical behavior between conventional NiTi, CM, M-Wire and CM-EDM alloy instruments for cyclic fatigue and torsion fracture - evaluation of fracture surface in scanning electron microscope

Furlan, Renan Diego

doi:10.11606/d.25.2019.tde-23012019-161605

Cited by 1 publication

(1 citation statement)

References 44 publications

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“…However, some studies have reported that this surface nish has an effect on the crack initiation process [32] and structural irregularities of the instrument surface may compromise its integrity during clinical use, making the les more susceptible to fracture [7], while others have shown that the cyclic fatigue associated with EDM was signi cantly greater than that for the conventionally manufactured CM les [20]. In the present study, EDM les showed better resistance to cyclic fatigue than the other les, which is in agreement with the ndings of several studies [12,33,34], but its resistance was still lower than that of the CM les, which is inconsistent with other ndings [35]. On the other hand, the EDM le showed a signi cantly longer fractured fragment length and separated at a larger diameter than all other les in both single and double canal curvatures.…”

Section: Discussioncontrasting

confidence: 52%

Comparison of Cyclic Fatigue Resistance of Five Heat Treated NiTi Rotary Systems in Single and Double Curved Canals.

Al-Obaida

Merdad

Alkhamis³

et al. 2021

Preprint

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BackgroundThe aim of this study was to compare cyclic fatigue resistance (CFR) and separation patterns during rotating movement of five heat-treated nickel titanium files in both single and double-curved canals. MethodsCFR was compared between five groups of 24 files each: HyFlex® EDM, HyFlex™ CM, Vortex Blue®, Protaper Next®, and One Curve, by determining the time needed to fracture (TTF) and the number of cycles to failure (NCF) in a cyclic fatigue testing device with a single 5-mm radius of curvature (ROC) and 60° angle, and a double curvature; coronal curvature (5 mm ROC and 60° angle) and apical curvature (2 mm ROC and 70° angle). The separation pattern was evaluated, and file fragment separated length were measured. One-way ANOVA and Tukey’s post-hoc were used to compare statistical differences between the groups. Scanning Electron Microscope (SEM) was used to investigate the fracture sites. Results HyFlex™ CM files displayed significantly higher CFR, followed by HyFlex® EDM and Vortex Blue® in single curvature canals, and Protaper Next® (PTN) in the double curvature canals, as observed by TFF and NCF. PTN group had the highest tendency for files to extrude apically after separation in both curvatures. ConclusionHyFlex™ CM instruments have superior resistance to cyclic flexural fatigue within single canals with single and double curvatures, followed by HyFlex® EDM and Vortex Blue® instruments. Protaper Next® files followed by One Curve had the highest tendency to extrude apically after separationClinical relevanceHyFlex™ CM instruments showed the highest safety in preparing canals with single or double curvatures, considering CFR.

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