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| Titel: |
Comparative study of the effect of in vitro and in vivo aging on morphology, microstructure and elemental composition of nickel-titanium orthodontic archwires. |
| Auteur: |
S. Zinelis M. Makou C. Gioka T. Eliades |
| Verschenen in: |
Hellenic orthodontic review |
| Paginering: | Jaargang 6 (2003) nr. 1 pagina's 45-58 |
| Jaar: |
2003 |
| Inhoud: |
AIM: Comparative study of microstructure, morphology and elemental composition of archwires retrieved and aged in vitro. MATERIAL AND METHOD: NiTi archwires were retrieved following a 2-month intraoral placement in 20 fully bonded orthodontic patients, whereas another 20 archwires were submerged in a 0.1 M lactic acid solution for the same time period. Morphology was studied with optical and scanning electron microscopy, elemental surface composition and molecular analysis of deposits were studied using X-ray microanalysis and ultra-red spectrometry, respectively; composition of wire mass was studied using fluorescent spectrometry and metal ion release in the aging solution was investigated using atomic emission spectrometry of inductively coupled plasma. RESULTS: Retrieved archwires demonstrated rough surfaces with craters, K and Na deposits, localized formations of Ca-P crystals and absorption of proteins and alcohols, in contrast to archwires aged in vitro which presented a slight increase in roughness. The microstructure of retrieved wires demonstrated localized crystal network destruction of the martensitic formations, probably due to loads developing during wire engagement in the bracket slot; on the other hand, wires aged in vitro showed no change. Nickel wire content ranged from 47% to 53%. The aging solution showed higher ferrum concentration resulting from the manufacturing process and attributed to higher ferrum solubility in relation to other alloy elements; nickel and titanium were in the order of one hundredth ppm. CONCLUSIONS: It seems that in vitro aging of NiTi archwires is not comparable to their clinical aging. As a result, application of this process does not provide any clinically valuable information. |
| Uitgever: |
Greek Orthodontic Society |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 2 van 8 gevonden artikelen
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