Micro-X-ray diffraction observation of nickel-titanium orthodontic wires in simulated oral environment

M. Iijima, W. A. Brantley, I. Kawashima, H. Ohno, W. Guo, Y. Yonekura, I. Mizoguchi

研究成果: Article査読

30 被引用数 (Scopus)


A micro-X-ray diffraction (micro-XRD) technique has been employed to determine the phases in two superelastic nickel-titanium orthodontic wires that exhibit shape memory in the oral environment and one superelastic nickel-titanium wire that does not exhibit shape memory in vivo. The micro-XRD analyses were performed over the clinically relevant temperature range of 0-55°C, which corresponds to the ingestion of cold and hot liquids, and both straight and bent (135°) test samples were analyzed. The results showed that for straight (as-received) test samples, the rhombohedral phase (R-phase) was definitely present in one shape memory wire product and perhaps in the other shape memory wire product, but was apparently absent in the superelastic wire product that did not display shape memory. Martensite was observed in all three wire products after bending. Phase transformations occurred with temperature changes simulating the oral environment for straight test samples of the two shape memory wires, but the micro-XRD pattern changed minimally with temperature for straight test samples of the superelastic wire and for bent test samples of all three wire products. The phase transformations revealed by micro-XRD were consistent with results recently found by temperature-modulated differential scanning calorimetry.

出版ステータスPublished - 2004 1月

ASJC Scopus subject areas

  • バイオエンジニアリング
  • セラミックおよび複合材料
  • 生物理学
  • 生体材料
  • 材料力学


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