Abstract
Introduction
Novel nickel-titanium rotary files with proprietary manufacturing techniques have
recently been marketed. The purpose of this study was to assess multiple autoclave
cycle effects on cyclic fatigue of GT Series X files (Dentsply Tulsa Dental Specialties,
Tulsa, OK) and Twisted Files (SybronEndo, Orange, CA)
Methods
A jig using a 5-mm radius curve with 90° of maximum file flexure was used to induce
cyclic fatigue failure. Files (n = 10) representing each experimental group (GT Series X 20/.04 and 20/.06; Twisted
Files 25/.04 and 25/.06) were first tested to establish baseline mean cycles to failure
(MCF). Experimental groups (n = 20) were then cycled to 25% of the established baseline MCF and then autoclaved.
Additional autoclaving was accomplished at 50% and 75% of MCF followed by continual
testing until failure. Control groups (n = 20) underwent the same procedures except autoclaving was not accomplished.
Results
The GT Series X (20/.04 and 20/.06) files showed no significant difference (p = 0.918/p = 0.096) in MCF for experimental versus control files. Twisted Files (25/.04) showed
no significant difference (p = 0.432) in MCF between experimental and control groups. However, the Twisted Files
(25/.06) experimental group showed a significantly lower (p = 0.0175) MCF compared with the controls.
Conclusions
Under the conditions of this evaluation, autoclave sterilization significantly decreased
cyclic fatigue resistance of one of the four file groups tested. Repeated autoclaving
significantly reduced the MCF of 25/.06 Twisted Files; however, 25/.04 Twisted Files
and both GT Series X files tested were not significantly affected by the same conditions.
Key Words
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Article info
Footnotes
Supported by the AAE Foundation.
This article is the work of the United States government and may be reprinted without permission. Opinions expressed herein, unless otherwise specifically indicated, are those of the authors. They do not represent the views of the Department of the Air Force or any other department or agency of the United States government.
Identification
Copyright
Published by Elsevier Inc.
