Comparison of autoclaving effects on torsional deformation and fracture resistance of three innovative endodontic file systems

Rhett B. Casper, Howard W. Roberts, Mark D. Roberts, Van T. Himel, Brian E. Bergeron

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Introduction: Recent innovative manufacturing techniques have produced nickel-titanium (NiTi) rotary instruments with reports of superior properties compared with standard NiTi files. These include Profile Vortex made from M-Wire (PV), Twisted Files (TF), and 10 Series files made from CM Wire (CM). Sterilization is recommended before use and is repeated if files are reused and/or carried forward between cases. The purpose for this study was to compare the effects of multiple autoclaving cycles on the torsional load resistance of these 3 new rotary endodontic files. Methods: PV, TF, and CM files (n = 100; size 25/.04) were divided into 5 groups (n = 20). Files were steam autoclaved for 1, 2, 3, and 7 sterilization cycles. A control group was not subjected to autoclaving. Files were tested in a torsiometer in general accordance with ISO 3630-1 standards. Torsional load and degrees of rotation to failure were recorded. Mean data were analyzed by using Kruskal-Wallace/Dunn post hoc tests (P <.05). Results: Autoclave cycles had no significant overall effect on file performance for any of the instrument systems tested. PV and CM displayed significantly greater resistance to torsional load than TF (P <.001) but were not different from each other (P >.05). Angular deflection values for TF and CM were significantly higher than for PV (P <.001), with TF demonstrating greater rotational distortion than CM (P <.05). Conclusions: Under the conditions of this study, repeated steam autoclaving did not affect torsional resistance for unused files of the systems evaluated. In addition, CM Wire files might have a combined advantage of greater torsional strength and high deformation before failure.

Original languageEnglish
Pages (from-to)1572-1575
Number of pages4
JournalJournal of Endodontics
Issue number11
StatePublished - Nov 2011


  • Controlled memory-wire
  • Twisted File
  • memory wire
  • nickle-titanium

ASJC Scopus subject areas

  • General Dentistry


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