Fracture of nickel-titanium superelastic alloy in sodium hypochlorite solution

Ken'ichi Yokoyama, Kazuyuki Kaneko, Eiji Yabuta, Kenzo Asaoka, Jun'ichi Sakai

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    23 Citations (Scopus)

    Abstract

    Fracture of the Ni-Ti superelastic alloy for endodontic instruments such as files was investigated with a sustained tensile-loading test in sodium hypochlorite (NaOCl) solution of various concentrations. It was found that the time to fracture was reduced when the applied stress exceeded the critical stress for martensite transformation. When the applied stress was higher than the critical stress, the 0.3 mm diameter wires of the Ni-Ti superelastic alloy sometimes fractured within 60 min. From the results of observations of the fracture surface using a scanning electron microscope, it was revealed that the fracture of the Ni-Ti superelastic alloy is significantly influenced by corrosion when the applied stress was higher than the critical stress for martensite transformation. The results of the present study suggest that one of the causes of the fracture of Ni-Ti files during clinical use is corrosion under the applied stress above the critical stress for martensite transformation in NaOCl solution.

    Original languageEnglish
    Pages (from-to)43-48
    Number of pages6
    JournalMaterials Science and Engineering A
    Volume369
    Issue number1-2
    DOIs
    Publication statusPublished - 2004 Mar 25

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    Keywords

    • Corrosion
    • Fracture
    • Ni-Ti
    • Sodium hypochlorite
    • Superelastic alloy

    ASJC Scopus subject areas

    • Materials Science(all)

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