Evaluation of cyclic and torsional fatigue resistance of several heat-treated reciprocating nickel-titanium instruments

Aust Endod J. 2023 Dec;49(3):524-529. doi: 10.1111/aej.12774. Epub 2023 Jul 13.

Abstract

This study investigated the cyclic fatigue and torsional resistance of Unicone Plus (UCP 25.06), Unicone (UC 25.06), Reciproc Blue (RB 25.08) and Wave One Gold (WOG 25.07) performed at body temperature (35° ± 1°C). Time and number of cycles to fracture (NCF), as well as torque and angular deflection were recorded. Fractured surfaces were evaluated by scanning electron microscopy (SEM). Data were analysed using one-way ANOVA and Holm-Sidak's tests for multiple comparison. The RB had a significantly higher time to fracture, followed by the WOG and UCP (p < 0.05). Regarding the NCF, there was no significantly difference between RB and WOG (p > 0.05). UC presented highest torque values and the lowest angular deflection (p < 0.05). SEM analysis demonstrated typical failures features in both cyclic and torsional fatigue tests. Overall, UC had the lowest time, NCF and angular deflection at fracture. RB presented the highest time to fracture and angular deflection values.

Keywords: cyclic fatigue; heat treatment; nickel-titanium; reciprocating instruments; torsional fatigue.

MeSH terms

  • Dental Alloys*
  • Dental Instruments
  • Equipment Design
  • Hot Temperature*
  • Materials Testing
  • Nickel
  • Root Canal Preparation
  • Stress, Mechanical
  • Titanium

Substances

  • Dental Alloys
  • titanium nickelide
  • Titanium
  • Nickel
  • nitinol

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