Restor Dent Endod.  2017 Nov;42(4):301-308. 10.5395/rde.2017.42.4.301.

The effects of autoclave sterilization on the cyclic fatigue resistance of ProTaper Universal, ProTaper Next, and ProTaper Gold nickel-titanium instruments

• Özyürek
• Yılmaz K
• Uslu G

• KMID: 2403071
• DOI: http://doi.org/10.5395/rde.2017.42.4.301

Abstract

OBJECTIVES
It was aimed to compare the cyclic fatigue resistances of ProTaper Universal (PTU), ProTaper Next (PTN), and ProTaper Gold (PTG) and the effects of sterilization by autoclave on the cyclic fatigue life of nickel-titanium (NiTi) instruments.
MATERIALS AND METHODS
Eighty PTU, 80 PTN, and 80 PTG were included to the present study. Files were tested in a simulated canal. Each brand of the NiTi files were divided into 4 subgroups: group 1, as received condition; group 2, pre-sterilized instruments exposed to 10 times sterilization by autoclave; group 3, instruments tested were sterilized after being exposed to 25%, 50%, and 75% of the mean cycles to failure, then cycled fatigue test was performed; group 4, instruments exposed to the same experiment with group 3 without sterilization. The number of cycles to failure (NCF) was calculated. The data was statistically analyzed by using one-way analysis of variance and post hoc Tukey tests.
RESULTS
PTG showed significantly higher NCF than PTU and PTN in group 1 (p < 0.05). Sterilization significantly increased the NCF of PTN and PTG (p < 0.05) in group 2. PTN in group 3 had significantly higher cyclic fatigue resistance than PTN group 4 (p < 0.05). Also, significantly higher NCF was observed for PTG in group 2 than in groups 3 and 4 (p < 0.05).
CONCLUSIONS
PTG instrument made of new gold alloy was more resistant to fatigue failure than PTN and PTU. Autoclaving increased the cyclic fatigue resistances of PTN and PTG.

Keyword

Endodontics; Gold-wire; M-wire; Nickel-titanium; Sterilization

MeSH Terms

Alloys
Endodontics
Fatigue*
Sterilization*
Alloys

Figure

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  Figure 1 The artificial canal that used in the present study (the radii and the angle of the curvature).

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  Figure 2 Scanning electron microscopic appearances of the ProTaper Universal (PTU), ProTaper Next (PTN), and ProTaper Gold (PTG) files after cyclic fatigue testing. View of the fractured surface (A) PTU, (C) PTN, and (E) PTG and high-magnification view of (B) PTU, (D) PTN, and (F) PTG instruments showing fatigue striations typical of cyclic fatigue (arrows). ProTaper Gold, Dentsply Maillefer, Ballaigues, Switzerland; ProTaper Next, Dentsply Maillefer; ProTaper Universal, Dentsply Maillefer.

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