Introduction: The purpose of this study was to evaluatethe torsional and cyclic fatigue resistance of the new Hy-flex EDM OneFile Coltene/Whaledent AG, Altstatten,Switzerland) manufactured by electrical discharge machining and compare the findings with the ones of Reciproc R25 (VDW, Munich, Germany) and WaveOnePrimary (Dentsply Maillefer, Ballaigues, Switzerland).Methods: One hundred-twenty new Hyflex EDM One-File (#25/0.08), Reciproc R25, and WaveOne Primaryfiles were used. Torque and angle of rotation at failureof new instruments (n = 20) were measured according to ISO 3630-1 for each brand. Cyclic fatigue resistancewas tested measuring the number of cycles to failurein an artificial stainless steel canal with a 60° angleand a 3-mm radius of curvature. Data were analyzedusing the analysis of variance test and the Student-Newman-Keuls test for multiple comparisons. The fracture surface of each fragment was examined with ascanning electron microscope.Results: The cyclic fatigue of Hyflex EDM was significantly higher than theone of Reciproc R25 and WaveOne Primary (P< .05 andP< .001, respectively). Hyflex EDM showed a lowermaximum torque load (P< .05) but a significantly higherangular rotation (P< .0001) to fracture than ReciprocR25 and WaveOne Primary. No significant difference was found comparing the maximum torque load, angular rotation, and cyclic fatigue of Reciproc R25 and WaveOne Primary (P> .05).Conclusions: The new Hyflex EDM instruments (controlled memory wire)have higher cyclic fatigue resistance and angle of rotation to fracture but lower torque to failure than Reciproc R25 and WaveOne Primary files (M-wire for both files).
|Titolo:||Torsional and Cyclic Fatigue Resistance of a New Nickel-titanium Instrument Manufactured by Electrical Discharge Machining|
PEDULLA', EUGENIO [Methodology] (Corresponding)
|Data di pubblicazione:||2016|
|Appare nelle tipologie:||1.1 Articolo in rivista|