Introduction: The aim of the present study was to evaluate the bending resistance and the dynamic and static cyclic fatigue life of Reciproc R40 and WaveOne large instruments.
Methods: A sample of 68 nickel-titanium instruments (25 mm in length) for use under reciprocation movement (Reciproc and WaveOne) from 3 different lots was tested. Reciproc R40 and WaveOne Large files, both of which had a nominal size of 0.40 mm at D0, were selected. The bending resistance was performed in 10 instruments of each system by using a universal testing machine. Dynamic and static models for cyclic fatigue testing were performed by using a custom-made device. For these tests, an artificial canal measuring 1.4 mm in diameter and 19 mm total length was fabricated from a stainless steel tube. Scanning electron microscopy analysis was performed to determine the mode of fracture. Statistical analysis was performed by using parametric methods, 1-way analysis of variance. Post hoc pair-wise comparisons were performed by using Tukey test for multiple comparisons.
Results: WaveOne instruments presented significantly higher bending resistance than Reciproc (P < .05). Moreover, Reciproc revealed a significantly longer cyclic fatigue life (P < .05) in both static and dynamic tests (P < .05).
Conclusions: Reciproc R40 instruments resisted dynamic and static cyclic fatigue significantly more than WaveOne Large instruments. Furthermore, WaveOne instruments presented significantly less flexibility than Reciproc.
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http://dx.doi.org/10.1016/j.joen.2013.10.013 | DOI Listing |
Odontology
January 2025
Department of General Surgery and Medical-Surgical Specialties, University of Catania, 95123, Catania, Italy.
The aim of this study was to assess the cyclic fatigue resistance of a single-file system (i.e., Hyflex EDM OneFile), during continuous rotation and reflex dynamic motion with and without irrigation.
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January 2025
College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. Electronic address:
This study delves into the feasibility of leveraging quasi-static component (QSC) generation during primary Lamb wave propagation to discern subtle alterations in the interfacial properties of a two-layered plate. Unlike the second-harmonic generation of Lamb waves, QSC generation doesn't necessitate precise phase-velocity matching but rather requires an approximate matching of group velocities to ensure the emergence of cumulative growth effects. This unique characteristic empowers the QSC-based nonlinear ultrasonic method to effectively surmount the limitations associated with inherent dispersion and multimode traits of Lamb wave propagation.
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December 2024
School of Science, Harbin Institute of Technology, Shenzhen 518055, China.
Fatigue failure poses a serious challenge for ensuring the operational safety of critical components subjected to cyclic/random loading. In this context, various machine learning (ML) models have been increasingly explored, due to their effectiveness in analyzing the relationship between fatigue life and multiple influencing factors. Nevertheless, existing ML models hinge heavily on numeric features as inputs, which encapsulate limited information on the fatigue failure process of interest.
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January 2025
Institut Langevin, École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris, Université Paris Sciences & Lettres, CNRS, Paris 7587, France.
Understanding the dynamic response of granular shear zones under cyclic loading is fundamental to elucidating the mechanisms triggering earthquake-induced landslides, with implications for broader fields such as seismology and granular physics. Existing prediction methods struggle to accurately predict many experimental and in situ landslide observations due to inadequate consideration of the underlying physical mechanisms. The mechanisms that influence landslide dynamic triggering, a transition from static (or extremely slow creeping) to rapid runout, remain elusive.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Institute of Clean Energy, Yangtze River Delta Research Institute, Northwestern Polytechnical University, Taicang 215400, China.
Continuous and interrupted low cycle fatigue tests were conducted on nuclear-grade S30408 stainless steel under different stress conditions at room temperature. Vickers hardness testing and microstructure characterization were performed on the fatigue samples with different fatigue states. The evolutionary mechanism of the microstructure defects in materials under fatigue cyclic loading was discussed.
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