Degradation in performance of orthodontic wires caused by hydrogen absorption during short-term immersion in 2.0% acidulated phosphate fluoride solution

Kazuyuki Kaneko, Ken'ichi Yokoyama, Keiji Moriyama, Kenzo Asaoka, Jun'ichi Sakai

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    34 Citations (Scopus)

    Abstract

    The purpose of this study was to investigate the degradation in performance of four major alloys of orthodontic wires, namely nickel-titanium, beta titanium, stainless steel, and cobalt-chromium-nickel, caused by hydrogen absorption during short-term immersion in an acid fluoride solutions. The hydrogen-related degradation of orthodontic wires after immersion in 2.0% acidulated phosphate fluoride solution at 37°C for 60 minutes was evaluated by a tensile test, scanning electron microscope observation, and hydrogen thermal desorption analysis. Upon immersion, the tensile strengths of the nickel-titanium and beta titanium wires decreased. Particularly, the nickel-titanium wire fractured before yielding, and the fracture mode changed from ductile to brittle. The amounts of absorbed hydrogen in the nickel-titanium and beta titanium wires were 200 and 100 mass ppm, respectively. On the other hand, the tensile strengths of the stainless steel and cobalt-chromium-nickel wires were only slightly affected by immersion. The results of this study suggest that degradation in performance of orthodontic wires of titanium alloys occurs because of hydrogen absorption even after a short-term immersion in fluoride solutions.

    Original languageEnglish
    Pages (from-to)487-495
    Number of pages9
    JournalAngle Orthodontist
    Volume74
    Issue number4
    Publication statusPublished - 2004 Aug

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    Keywords

    • Corrosion
    • Fluoride
    • Hydrogen embrittlement
    • Orthodontic wire

    ASJC Scopus subject areas

    • Dentistry(all)

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