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Updated: Jan 18, 2026

Ultrasonic Fatigue Testing in the Tension-Compression Mode
Published on: March 7, 2018
Resistance to cyclic fatigue of reciprocating instruments determined at body temperature and phase transformation
Raymond Scott1, Ana Arias1,2, José C Macorra2
1Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California, USA.
Abstract:
The purpose of this study was to compare cyclic fatigue (CF) resistance of reciprocating instruments at body temperature and relate the findings to their martensitic transformation temperatures. Contemporary nickel-titanium (NiTi) reciprocating instruments WaveOne Primary, WaveOne Gold Primary and EdgeFile X1 (n = 20 each and #25 tip diameter) were tested for CF resistance at body temperature (37 ± 1°C). Instruments were actioned according to manufacturer guidelines until fracture occurred in a simulated canal (angle of curvature = 60°, radius of curvature = 3 mm and centre of curvature = 5 mm from the tip). Time to fracture was recorded, and data analysed using Weibull analysis. Two instruments of each were tested using differential scanning calorimetry (DSC) to assess phase transformation temperatures. Reciprocating instruments manufactured with new alloys seem to be safer to CF than those manufactured with traditional M-Wire at body temperature. Martensitic transformation temperatures seem not to relate with fatigue behaviour for reciprocating motions.
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