Introduction: Recent improvements in alloys, kinematics, and concepts have been combined to increase the cyclic fatigue resistance of nickel-titanium (NiTi) instruments. The aim of this study was to compare the cyclic fatigue resistance of new M-Wire reciprocating WaveOne (Dentsply Maillefer, Ballaigues, Switzerland) and Reciproc (VDW GmbH, Munich, Germany) files at 2 levels.
Methods: Sixty Reciproc and 60 WaveOne new files were fixed to a specifically designed device and tested in tempered steel canals with a 3-mm radius and a 60° angle of curvature. The motor used was programmed as defined by each manufacturer, and the specific reciprocating motion was followed. Thirty files of each brand were tested at 5 mm, and 30 were tested at 13 mm from their tips. The time to failure was registered. Weibull analysis was used to calculate the mean life, beta, and eta parameters.
Results: The probability of the mean life was higher for Reciproc than WaveOne files at both levels, with the probability of the Reciproc mean life being 62% higher than that of WaveOne at 5 mm from the tip and 100% higher at 13 mm (all statistically significant). The probability of the mean life was higher at 5 mm than at 13 mm in both systems. The results may have been partially conditioned by the different motions that manufacturers propose for each system.
Conclusions: Reciproc files were more resistant to cyclic fatigue than WaveOne files at both distances from the tip. Both systems had greater cyclic fatigue resistance at 5 mm than at 13 mm from the tip.
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http://dx.doi.org/10.1016/j.joen.2012.05.022 | 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.
View Article and Find Full Text PDFUltrasonics
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.
View Article and Find Full Text PDFMaterials (Basel)
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.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
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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