Introduction: The aim of this study was to compare the nickel released from 3 kinds of orthodontic brackets: new conventional stainless steel, recycled stainless steel, and nickel-free brackets.
Methods: This in-vitro study was performed by using a classic batch procedure. Samples were immersed in artificial saliva at various acidities (pH 4.2, 6.5, 7.6) over an extended time interval (0.25, 1, 24, 48, and 120 hours). The amount of nickel released was determined by using an atomic absorption spectrophotometer and an inductively coupled plasma atomic emission spectrometer. Statistical analysis included a linear regression model for repeated measures, with calculation of Huber White robust standard errors to account for intrabracket correlation of data. For post-hoc comparisons, the Bonferroni correction was applied.
Results: The recycled brackets released the most nickel (74.02 +/- 170.29 microg per gram); the new stainless steel brackets released 7.14 +/- 20.83 microg per gram. The nickel-free brackets released the least nickel (0.03 +/- 0.06 microg per gram). All the differences among the groups were statistically significant (P = 0.000).
Conclusions: Reconditioned brackets released the most nickel. Moreover, the highest nickel release was recorded in the 2 experiments performed at pH 4.2; it was lower at pH 6.5 and 7.6. Conversely, no relevant differences were observed overall between the maxillary and mandibular arches.
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http://dx.doi.org/10.1016/j.ajodo.2008.07.021 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
The aging population necessitates a critical need for medical devices, where polymers-based surface lubrication coating is essential for optimal functionality. In fact, lubrication and mechanical requirements vary depending on the service environment of different medical devices. Until now, key mean is still blank for general preparation of hydrophilic polymers-based lubrication coatings with on-demand mechanics and lubricity.
View Article and Find Full Text PDFActa Bioeng Biomech
September 2024
Faculty of Materials Science and Engineering, Warsaw University of Technology, Warsaw, Poland.
The aim of the study was to investigate the influence of the nitrocarburizing process carried out in low temperature plasma using the active screen at 440 °C on the structure and physicochemical properties of the 316LVM steel. In the paper, results of micro-structure and phase composition of the layers, roughness, and surface wettability, potentiodynamic pitting corrosion resistance, penetration of ions into the solution as well as biological tests were present. The studies were conducted for the samples of both mechanically polished and nitrocarburized surfaces, after sterilization, and exposure to the Ringer's solution.
View Article and Find Full Text PDFAnal Chem
January 2025
ICGM, Univ. Montpellier, CNRS, ENSCM, 34000 Montpellier, France.
In this contribution, we apply our newly developed ball-milling platform, which combines Raman spectroscopy and thermal (IR) imaging, as well as acoustic and high-speed optical video recordings, to the synthesis and transformation of citric acid-isonicotinamide (1:2) cocrystal polymorphs in transparent PMMA jars. Particularly, we demonstrate how Raman, temperature, acoustic, and video data are complementary and enable detection and connection of chemical and physical events happening during ball-milling in a time-resolved manner. Importantly, we show that the formation of the three cocrystal polymorphs can be detected through acoustic analyses solely.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Northeastern University, Corrosion and Protection Center, NO. 3-11, Wenhua Road, Heping District, Shenyang, P. R. China, Shenyang, CHINA.
The dense passive film on 316L stainless steel is the key in its corrosion resistance. Its interactions with an electroactive biofilm are critical in deciphering microbial corrosion. Herein, an in-depth investigation using genetic manipulations and addition of an exogenous electron mediator found that extracellular electron transfer (EET) mediated by the electroactive S.
View Article and Find Full Text PDFHeliyon
January 2025
Department of Technologies and Structures, Technical University of Liberec, Czech Republic.
This study explores and discusses the design, the manufacturing and the morphology of three-dimensional (3D) multilayered weft interlaced woven fabrics using stainless steel fibers on the electromagnetic shielding efficiency (SE). Design solutions of 3D multilayered interlaced fabrics in relation to electromagnetic shielding efficiency are still not sufficiently investigated. Moreover, this study aims to analyze the differences in the internal geometry of 3D multilayered weft interlaced fabrics with different number of layers and frequency of connecting points in multilayered woven fabrics on electromagnetic SE.
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