Corrosion Behavior and Surface Structure of Orthodontic Ni-Ti Alloy Wires

Masahiro Iijima, Kazuhiko Endo, Hiroki Ohno, Yasuyuki Yonekura, Itaru Mizoguchi

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


The corrosion behaviors of a commercial Ni-Ti alloy orthodontic wire and a polished plate with same composition in 0.9% NaCl and 1 % lactic acid solutions were examined using an electrochemical technique, an analysis of released ions, and a surface analysis by X-ray photoelectron spectroscopy (XPS). The effect of polishing the wire on the corrosion was also examined. The XPS analysis demonstrated the presence of a thick oxide film mainly composed of TiO2 with trace amounts of Ni hydroxide, which had formed on the wire surface during the heat treatment and subsequent pickling processes. This oxide layer contributed to the higher resistance of the as-received wire to both general and localized corrosion in 0.9% NaCl solution, compared with that of the polished plate and the polished wire. The thick oxide layer, however, was not stable and did not protect the orthodontic wire from corrosion in 0.1% lactic acid solution.

Original languageEnglish
Pages (from-to)103-113
Number of pages11
JournalDental Materials Journal
Issue number1
Publication statusPublished - 2001 Mar


  • Corrosion
  • Ni-Ti alloy
  • Orthodontic wire


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