SEM observations of nickel-titanium rotary endodontic instruments that fractured during clinical use

Satish B. Alapati, William A. Brantley, Timothy A. Svec, John M. Powers, John M. Nusstein, Glenn S. Daehn

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Abstract

Numerous discarded ProFile GT, ProFile, and ProTaper nickel-titanium rotary instruments obtained from two graduate endodontic clinics were examined by scanning electron microscopy. These instruments had an unknown history of clinical use and had fractured or experienced considerable permanent torsional deformation without complete separation. The failure processes generally exhibited substantial ductile character, evidenced by a dimpled rupture fracture surface. Crack propagation at grain boundaries and cleavage surfaces indicative of transgranular fracture were observed for some specimens. It appeared that oxide particles from the manufacturing process served as nucleating sites for the microvoids, leading to dimpled rupture. A previously unreported fracture mode also was observed, in which crack propagation, approximately parallel to the local flute orientation, connected pitted regions on the surface. Combining present and previous scanning electron microscopy observations of clinically failed instruments, suggestions are offered for improving their fracture resistance.

Original languageEnglish (US)
Pages (from-to)40-43
Number of pages4
JournalJournal of endodontics
Volume31
Issue number1
DOIs
StatePublished - Jan 2005

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ASJC Scopus subject areas

  • Dentistry(all)

Cite this

Alapati, S. B., Brantley, W. A., Svec, T. A., Powers, J. M., Nusstein, J. M., & Daehn, G. S. (2005). SEM observations of nickel-titanium rotary endodontic instruments that fractured during clinical use. Journal of endodontics, 31(1), 40-43. https://doi.org/10.1097/01.DON.0000132301.87637.4A