Effect of Clinical Use on the Cyclic Fatigue Resistance of ProTaper Nickel-Titanium Rotary Instruments

Hani F. Ounsi, Ziad Salameh, Thakib Al-Shalan, Marco Ferrari, Simone Grandini, David H. Pashley, Franklin Chi Meng Tay

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

The resistance of ProTaper (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium rotary instruments to cyclic fatigue was examined after their initial use in straight or curved canals in vivo. These instruments were rotated freely inside a steel phantom until separation. The number of rotations before failure and the lengths of the separated fragments were compared with data derived from new instruments under the same experimental setup (n = 20). With the exception of F1 and F3, instruments previously used in curved canals were more susceptible to cyclic fatigue than those previously used in straight canals (p < 0.05). Separation occurred predominantly at the D10 to D12 level. For the F series, a negative correlation (p < 0.05) was observed between the number of rotations before failure and the file diameters at their separation levels. ProTaper F3 instruments are highly susceptible to cyclic fatigue failure and should be reused with caution irrespective of whether they are initially used for shaping straight or curved canals.

Original languageEnglish (US)
Pages (from-to)737-741
Number of pages5
JournalJournal of Endodontics
Volume33
Issue number6
DOIs
StatePublished - Jun 1 2007

Keywords

  • Cyclic fatigue
  • fatigue zone
  • fractographic analysis
  • instrument separation
  • nickel-titanium
  • overload zone
  • rotational bending

ASJC Scopus subject areas

  • Dentistry(all)

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