Corrosion Behaviour and Surface Modification of Intra-orally Engaged Orthodontic Ni-Ti Wires

2017 ◽  
Vol 68 (5) ◽  
pp. 1077-1080
Author(s):  
Krisztina Martha ◽  
Alexandru Ogodescu ◽  
Cristina Ioana Bica ◽  
Cristina Molnar Varlam
Keyword(s):  
Chemical Structure ◽  
Corrosion Behaviour ◽  
Sem Analysis ◽  
Orthodontic Appliance ◽  
Orthodontic Wires ◽  
Surface Corrosion ◽  
Patient Health ◽  
Almost All ◽  
Scanning Electron Microscope Method ◽  
Surface Changes

Almost all orthodontic wires suffer from corrosion as they are intra-orally engaged. This chemical structure alteration appears on the surface of these wires, surface topography can be easily visualised with scanning electron microscope method. The aim of our study was to assess the intraoral corrosion of the retrieved orthodontic Ni-Ti archwires. Archwire retrieval procedure yielded approximately 30 retrieved wires, placed intra-orally for 1-5 months. SEM analysis was performed and surface changes were interpreted. Our SEM results showed, that surface corrosion and pitting can be seen on the surface of retrieved Ni-Ti wires, the depth of corrosion depends on the time wires have been engaged in the oral cavity. With regards of metal liberation consequently surface corrosion, practitioners should be avare of these chemical changes which can affect the resistence of the orthodontic appliance and patient health.

scholarly journals TOXICOLOGICAL AND HYGIENIC CHARACTERISTICS OF MYCOTOXIN STERIGMATOCYSTIN AND METHODS FOR ITS DETERMINATION IN FOOD PRODUCTS

2019 ◽  
Vol 98 (1) ◽  
pp. 105-117 ◽  
Author(s):  
Irina B. Sedova ◽  
M. G. Kiseleva ◽  
L. P. Zakharova ◽  
V. A. Tutelyan
Keyword(s):  
Chemical Structure ◽  
Web Of Science ◽  
Food Products ◽  
International Agency ◽  
Primary Target ◽  
Teratogenic Effects ◽  
Similar Chemical ◽  
Food And Feed ◽  
International Data ◽  
Almost All

The present issue reviews literature and own research data and gives toxicological and hygienic characteristic of sterigmatocystin. This mycotoxin is produced by fungi of Aspergillus, Bipolaris, Chaetomium, Emiricella species, and is found in cereals, food products (bread, cheese, spices, coffee, dietary supplements) and feed. Sterigmatocystin being a biogenic precursor of aflatoxin B1, has similar chemical structure and exhibits the same toxicological properties, but its toxicity is ten times lower. However, these toxins are rarely detected together. A. versicolor and A. nidulans do not have enzymes necessary for the conversion of sterigmatocystin into aflatoxins, on the contrary, A. flavus and А. parasiticus transform almost all STC into aflatoxins. Sterigmatocystin has been recognized by International Agency for Research on Cancer (IARC) as a 2B carcinogen (possibly carcinogenic to humans). The primary target organ for both mycotoxins is liver. Sterigmatocystin shows mutagenic, toxic and teratogenic effects in animals. Up to date national and international data on sterigmatocystin occurrence in different products is summarized, analytical methods of the determination are reviewed, hygienic assessment of the STC as a priority pollutant is given in the present paper. Also information on STC exposure assessment with regard to different kinds of foodstuff in different countries is being reported, available data on maximum levels of STC in food and feed is discussed. However, data on toxin’s occurrence in food is insufficient for elaboration of hygienic regulations on allowable mycotoxin’s concentration in priority products. Databases Web of Science, PubMed, E-library, CyberLeninka were used when searching the literature.

Synthesis of Catechin-Gelatin Nanofiber by Electrospinning

2017 ◽  
Vol 887 ◽  
pp. 96-99 ◽  
Author(s):  
Muhamad Nasir ◽  
Dita Apriani
Keyword(s):  
Polyethylene Oxide ◽  
Chemical Structure ◽  
Sem Analysis ◽  
Electrospinning Process ◽  
Vibration Band ◽  
Ftir Analysis ◽  
Tuna Fish ◽  
Bioactive Component ◽  
Cosmetic Industry ◽  
Nanofiber Diameter

Catechin and gelatin are important natural products for food, medical, pharmaceutical and cosmetic industry. We have successfully synthesized catechin-gelatin nanofiber by electrospinning process. Catechin-gelatin nanofiber was synthesized by using gelatin from yellow fin skin tuna fish as biopolymer, polyethylene oxide (PEO) as spinnability improver polymer, acetic acid as solvent and catechin as bioactive component, respectively. Morphology and structure of bioactive catechin-gelatin nanofiber were characterized by scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FTIR), respectively. SEM analysis showed that morphology of nanofiber was very smooth without bead on nanofiber string. The average of catechin-gelatin nanofiber diameter was 389 nm. FTIR analysis results were used to confirm structure of catechin-gelatin nanofiber. Catechin-gelatin nanofiber has vibration band peak of amide A (N-H) at 3289,043 cm-1 and amide B (N-H) 3062,310 cm-1, amide I (C=O) at 1643,812 cm-1, amide II (N-H and CN) at 1538,949 cm-1, amide III (C-N) at 1237,11 cm-1 from gelatin, C-O-C from PEO at 1143,583 cm-1, and vibration band peak OH at 3200-3600 cm-1, and at C-O ether around 1300-1100 from catechin, respectively. FTIR spectra showed us that there is no change in chemical structure of gelatin and catechin in nanofiber which was produced by electrospinning process. Catechin-gelatin nanofiber can inhibit S. Aureus bacteria around 43.38%

scholarly journals Experimental study of the influence of crack width due to corrosion behaviour using different measurement methods and different exposures

2019 ◽  
Vol 289 ◽  
pp. 08005
Author(s):  
Martin Schneider ◽  
Georg Gardener
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Corrosion Behaviour ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Chloride Ions ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Surface Corrosion ◽  
Potential Mapping

Corrosion of reinforcing steel has a great influence in reducing the lifetime of concrete structures; Carbonation of the concrete pore solution causes surface corrosion on the steel and diffusion of chloride ions through the capillary system of the concrete cover causes pitting corrosion on the steel surface. Corrosion of metals is highly dependent on the environmental conditions. Exposure to chloride ions can be critical to the service life of reinforced concrete structures. The durability of reinforced concrete structures exposed to deicing salt or marine environments can be affected by impact of chloride ions. Detection methods for the rate of corrosion of non-destructive and destructive procedures were analysed. The potential mapping applied on the concrete surface was discussed as a standard method for corrosion detection and will be explained in detail including the application boundaries of the method. It is assumed that the corrosion behaviour of reinforcing steel depends on crack widths. To analyse that, 8 coated and 8 uncoated test samples with different concrete strength classes were used. The concrete objects were exposed to a 3% sodium chloride solution. The corrosion behaviour of reinforcing steel is analysed by using potential mapping with different reference electrodes (Ag/AgCl and Cu/CuSO4). The results show a significant correlation between crack size and protection system on the surface. The maximum crack width with a low indication of corrosion was found to be 0.1 mm.

The chloride corrosion behaviour of four orthodontic wires

1983 ◽  
Vol 10 (2) ◽  
pp. 121-128 ◽  
Author(s):  
N. K. SARKAR ◽  
W. REDMOND ◽  
B. SCHWANINGER ◽  
A. J. GOLDBERG
Keyword(s):  
Corrosion Behaviour ◽  
Orthodontic Wires ◽  
Chloride Corrosion

scholarly journals Structure, Composition, and Mechanical Properties of Australian Orthodontic Wires

2009 ◽  
Vol 79 (1) ◽  
pp. 97-101 ◽  
Author(s):  
Brian M. Pelsue ◽  
Spiros Zinelis ◽  
T. Gerard Bradley ◽  
David W. Berzins ◽  
Theodore Eliades ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Vickers Hardness ◽  
Modulus Of Elasticity ◽  
Sem Analysis ◽  
Orthodontic Wires ◽  
Vickers Hardness Number ◽  
X Ray ◽  
Level Of Significance ◽  
Lower Tensile Strength

Abstract Objective: To investigate the surface morphology, structure, elemental composition, and key mechanical properties of various sizes and tempers of Australian wires. Materials and Methods: Three types of Australian wire were used: 0.016″ regular, 0.018″ regular+, and 0.018″ special+ (A.J. Wilcock, Whittlesea, Victoria, Australia). Each type of wire was subjected to scanning electron microscopy (SEM) analysis, x-ray energy dispersive spectroscopy (EDS) investigation, Vickers hardness testing, and tensile testing. The modulus of elasticity and ultimate tensile strength were determined. Hardness, modulus, and strength data were analyzed with one-way analysis of variance (ANOVA) and Tukey testing at the .05 level of significance. Results: All three types of Australian wire were found to possess considerably rough surfaces with striations, irregularities, and excessive porosity. All three wire types had high levels of carbon and a similar hardness, which ranged within 600 VHN (Vickers hardness number), and a similar modulus of elasticity (173 to 177 GPa). The 0.018″ special+ had a significantly lower tensile strength (1632 MPa) than the 0.016″ regular and the 0.018″ regular+ wire (2100 MPa). Conclusions: Australian wires did not show variation implied by the size or temper of the wires.

An introduction of chemical structure coding in the X-ray Powder Diffraction File

2000 ◽  
Vol 15 (1) ◽  
pp. 38-41
Author(s):  
Wei Lianhu ◽  
Xiao Yunde ◽  
Zhang Jinbei ◽  
Lin ShaoFan
Keyword(s):  
Powder Diffraction ◽  
Chemical Structure ◽  
Computer Application ◽  
Improved Method ◽  
Powder Diffraction File ◽  
X Ray ◽  
Chemical Structures ◽  
And Topology ◽  
Connection Table ◽  
Almost All

A special computer storage method for chemical structures is illustrated in this article. With an improved method of two-dimensional connection table and topology, we can fit almost all chemical structures and display them very conveniently. We have used this method in the PDF (X-Ray Powder Diffraction File) database, which contains many special structures.Key words: database, computer application, chemical structure

Effect of Silver Content on Microstructure and Corrosion Behavior of Material Prepared from Silver Coated Iron Powder

2014 ◽  
Vol 782 ◽  
pp. 499-502
Author(s):  
Monika Hrubovčáková ◽  
Miriam Kupková ◽  
Andrea Fedorková ◽  
Renáta Oriňáková ◽  
Adam Zeleňák
Keyword(s):  
Corrosion Behavior ◽  
Electroless Deposition ◽  
Silver Content ◽  
Corrosion Behaviour ◽  
Sem Analysis ◽  
Iron Matrix ◽  
Iron Powders ◽  
Good Material ◽  
Polarization Technique ◽  
Hank’S Solution

Iron was considered a good material candidate for temporary implants in cardiovascular and orthopedic surgery. Mechanical properties of iron are attractive, however, a higher degradation rate is required. The contribution deals with the effect of silver content on microstructure and corrosion behavior of materials prepared from Ag coated iron powders. Using electroless deposition, Fe-powders with 0.29 and 2.1 wt.% of silver were prepared. Cylindrical specimens compacted at a pressure of 200 MPa were isothermally sintered at 1120°C for 60 min. The microstructure of the sintered specimens consisted of iron matrix with Ag-precipitates. The corrosion behaviour of sintered compacts was studied using the potentiodynamic polarization technique in Hank’s solution and complemented with SEM analysis. It was found out that corrosion resistance of material decreased with an increase in silver content.

scholarly journals Effect of Eugenol on Streptococcus mutans Adhesion on NiTi Orthodontic Wires: In Vitro and In Vivo Conditions

2021 ◽  
Author(s):  
Nassiba Fatene ◽  
Khadija Mounaji ◽  
Abdelaziz Soukri
Keyword(s):  
Streptococcus Mutans ◽  
Sem Analysis ◽  
Syzygium Aromaticum ◽  
White Spot Lesions ◽  
Orthodontic Wires ◽  
Niti Wires ◽  
Post Hoc ◽  
Bacterial Effect

Abstract Objective The purpose of this study was to compare the antibacterial effect of two types of Eugenol against Streptococcus mutans and then assess the effect of different concentrations of two types of Eugenol on S. mutans adhesion on Nickel-Titanium (NiTi) orthodontic wires in comparison to in vivo wires with fluoride-based hygiene regimen. Material and methods Culture of Streptococcus mutans with NiTi orthodontic wires was done. Different media were prepared by adding 100%, 50%, 25%, and 12.5% of two origins of Eugenol (one biological obtained by hydrodistillation of Syzygium aromaticum and one chemical already prepared available in drugstores for dental use (Idental, MOROCCO, lot number: UAN/17–211/1). Three sizes of NiTi wires (0.016 inch, 0.016 × 0.022 inch, 0.017 × 0.025 inch) were retrieved from adult patients undergoing orthodontic treatment after 1 month of setting them up in the mouth. After incubation, colony forming unites were calculated and a SEM analysis was done to the surface of each wire. ANOVA test was done between all groups to find statistical differences and post-hoc t-test with Bonferroni analysis was performed to elucidate differences between all groups with α = 0.05. Results Eugenol has an anti-bacterial effect against S. mutans. The biological Eugenol has greater effect than the chemical one. The same observations were done for anti-adherent effect, the biological Eugenol demonstrated the highest anti-adherent effect at all concentrations while the effect of the chemical Eugenol was the lowest. Conclusions The origin and the extraction mode of Eugenol have a crucial role in its antimicrobial and anti-adherent effect. Eugenol might constitute an alternative to Fluoride because it has an anti-adherent effect, limiting the incidence of white spot lesions.

scholarly journals Mechanical properties of orthodontic wires covered with a polyether ether ketone tube

2018 ◽  
Vol 88 (4) ◽  
pp. 442-449 ◽  
Author(s):  
Nobukazu Shirakawa ◽  
Toshio Iwata ◽  
Shinjiro Miyake ◽  
Takero Otuka ◽  
So Koizumi ◽  
...  
Keyword(s):  
Frictional Force ◽  
Color Difference ◽  
Orthodontic Appliances ◽  
Orthodontic Wires ◽  
Polyether Ether Ketone ◽  
Orthodontic Wire ◽  
Before And After ◽  
Ether Ketone ◽  
Coated Wires ◽  
Almost All

ABSTRACT Objectives: To evaluate the esthetics and frictional force of an orthodontic wire passed through a newly designed tube made of a polyether ether ketone (PEEK) resin. Materials and Methods: Two types of standard PEEK tubes were prepared at 0.5 × 0.6ф and 0.8 × 0.9ф, and different archwires were passed through the tubes. Color values were determined according to brightness and hues. Friction was assessed with different bracket-wire combinations, and surface roughness was determined by stereomicroscopy before and after the application of friction. Results: The PEEK tube showed a color difference that was almost identical to that of coated wires conventionally used in clinical practice, indicating a sufficient esthetic property. The result of the friction test showed that the frictional force was greatly reduced by passing the archwire through the PEEK tube in almost all of the archwires tested. Conclusions: Use of the new PEEK tube demonstrated a good combination of esthetic and functional properties for use in orthodontic appliances.

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