Journal Article

Surface characterization of retrieved NiTi orthodontic archwires

T Eliades, G Eliades, AE Athanasiou and TG Bradley

in The European Journal of Orthodontics

Published on behalf of European Orthodontics Society

Volume 22, issue 3, pages 317-326
Published in print June 2000 | ISSN: 0141-5387
Published online June 2000 | e-ISSN: 1460-2210 | DOI: https://dx.doi.org/10.1093/ejo/22.3.317
Surface characterization of retrieved NiTi orthodontic archwires

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The structure and morphological condition of retrieved NiTi orthodontic archwires was evaluated and any possible alterations in the surface composition of the alloy following 1-6 months in vivo were characterized. NiTi wires (GAC, German Orthodontics, ORMCO) of various cross-sections were collected through a retrieval protocol and were subjected to multi-technique characterization.

Optical microscopy revealed islands of amorphous precipitants and accumulated microcrystalline particles. Micro MIR-FTIR investigation of the retrieved samples demonstrated the presence of a proteinaceous biofilm, the organic constituents of which were mainly amide, alcohol, and carbonate. Scanning electron microscope and X-ray micro-analysis showed that the elemental species precipitated on the material surface were Na, K, Cl, Ca, and P, forming NaCl, KCl, and Ca-P precipitates. Increased intra-oral exposure was consistently associated with the presence of a mature film, while evidence of alloy delamination, pitting, and crevice corrosion, as well as a notable reduction in the alloy grain size was observed.

Intra-oral exposure of NiTi wires alters the topography and structure of the alloy surface through surface attack in the form of pitting or crevice corrosion or formation of integuments. Further in vivo research is required to resolve the implications of the described ageing pattern in the corrosion resistance of the alloy, the potential for nickel leaching, as well as bracket-archwire friction variants.

Journal Article.  0 words. 

Subjects: Restorative Dentistry and Orthodontics

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