Potential relationship between design of nickel-titanium rotary instruments and vertical root fracture

Hyeon Cheol Kim, Min Ho Lee, Jiwan Yum, Antheunis Versluis, Chan Joo Lee, Byung Min Kim

Research output: Contribution to journalArticle

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Abstract

Introduction: Nickel-titanium (NiTi) rotary files can produce cleanly tapered canal shapes with low tendency of transporting the canal lumen. Because NiTi instruments are generally perceived to have high fracture risk during use, new designs have been marketed to lower fracture risks. However, these design variations may also alter the forces on a root during instrumentation and increase dentinal defects that predispose a root to fracture. This study compared the stress conditions during rotary instrumentation in a curved root for three NiTi file designs. Methods: Stresses were calculated using finite element (FE) analysis. FE models of ProFile (Dentsply Maillefer, Ballaigues, Switzerland; U-shaped cross-section and constant 6% tapered shaft), ProTaper Universal (Dentsply; convex triangular cross-section with notch and progressive taper shaft), and LightSpeed LSX (Lightspeed Technology, Inc, San Antonio, TX; noncutting round shaft) were rotated within a curved root canal. The stress and strain conditions resulting from the simulated shaping action were evaluated in the apical root dentin. Results: ProTaper Universal induced the highest von Mises stress concentration in the root dentin and had the highest tensile and compressive principal strain components at the external root surface. The calculated stress values from ProTaper Universal, which had the biggest taper shaft, approached the strength properties of dentin. LightSpeed generated the lowest stresses. Conclusion: The stiffer file designs generated higher stress concentrations in the apical root dentin during shaping of the curved canal, which raises the risk of dentinal defects that may lead to apical root cracking. Thus, stress levels during shaping and fracture susceptibility after shaping vary with instrument design.

Original languageEnglish (US)
Pages (from-to)1195-1199
Number of pages5
JournalJournal of endodontics
Volume36
Issue number7
DOIs
StatePublished - Mar 19 2010

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Dentin
Finite Element Analysis
Dental Pulp Cavity
Switzerland
Technology
nitinol
CMW cement

All Science Journal Classification (ASJC) codes

  • Dentistry(all)

Cite this

Potential relationship between design of nickel-titanium rotary instruments and vertical root fracture. / Kim, Hyeon Cheol; Lee, Min Ho; Yum, Jiwan; Versluis, Antheunis; Lee, Chan Joo; Kim, Byung Min.

In: Journal of endodontics, Vol. 36, No. 7, 19.03.2010, p. 1195-1199.

Research output: Contribution to journalArticle

Kim, Hyeon Cheol ; Lee, Min Ho ; Yum, Jiwan ; Versluis, Antheunis ; Lee, Chan Joo ; Kim, Byung Min. / Potential relationship between design of nickel-titanium rotary instruments and vertical root fracture. In: Journal of endodontics. 2010 ; Vol. 36, No. 7. pp. 1195-1199.
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