Background: The demand for esthetic orthodontic appliances is increasing; so the esthetic orthodontic archwires were introduced. Among them, Teflon and Epoxy coated stainless steel archwires. The amount of force available from the archwire depends on the structural properties and susceptibility to corrosion. All metallic alloys are changed during immersion in artificial saliva, chlorhexidine mouthwash andtoothpaste, but their behaviors differ from one type to another. They corrode at different rates, which lead to decrease the amount of force applied to the teeth. This in vitro study was designed to evaluate the corrosion pits in stainless steel archwires coated with Teflon and with Epoxy in dry and after immersion in artificial saliva, chlorhexidine(0.2%( (Parodontax) and toothpaste media (Sensodyne) for (1, 7 and 28) days intervals. Moreover, this study is intended to compare the corrosion pits for each type of archwires at these different media among all intervals. Materials and Methods: In this study, two hundred forty pieces of orthodontic wires of Teflon (Hubit) coated Stainless steel (120 pieces) and epoxy (Orthotechnology) coated Stainless steel (120 pieces), rectangular in cross section, size (0.019 x 0.025) inch and 15mm in length divided into four groups according to immersion media: (dry environment group, artificial saliva group, chlorhexidine group and toothpaste group). The atomic force microscope was used to measure the corrosion pits for all samples at dry and wet conditions and after different immersion periods. Results: Statistical analysis showed that there was a highly significant increase in the corrosion pits of Teflon coated stainless steel archwires (P ≤ 0.05) in wet environment at 28 days immersion period.The highest corrosion pits were found in the toothpaste medium for the two archwire types at 28 days immersion period. Conclusion: We can conclude that Epoxy coatedstainless steel archwires are indicated to be used above Teflon coated stainless steel archwires in terms of corrosion resistance. IfTeflon coated stainless steel archwires should to be used, they should be change in shorter periods than Epoxy coated stainless steel archwires type Key words: Esthetic coated archwire, corrosion, Teflon, Epoxy, wet environment, AFM.
Oxidative stress is oxidative damage caused by free radicals and reactive oxygen species (ROS). These ROS can cause oxidative damage to cellular components, including membrane lipids, receptors, enzymes, proteins, and nucleic acids. It would eventually lead to cell apoptosis and the appearance of certain pathological conditions. This work investigates the antioxidant potentials of chamomile extract in vitro by evaluating the extract activity to scavenge 2,2-Diphenyl-1-picrylhydrazyl (DPPH), also in vivo by investigating its effects on oxidative stress-induced rats by assessing the total oxidant status (TOS) and total antioxidant capacity in the radiation exposed rats with and without the treatment with chamomile extract. The results
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The problem of the study is the main question (Can tourism planning address the phenomenon of unemployment in Iraq ?) , And the importance of the study in the fact that the tourism sector can become an effective development alternative in many countries, especially Iraq, as tourism contributes to diversify sources of income and stimulate other economic sectors , We know how important Iraq's qualifications are in the field of tourism and what it can generate on the public treasury, To confirm the current study on the need to pay attention to tourism planning for its role in providing employment opportunities that reduce the unemployment rate in the future.
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... Show MoreDensity data of alum chrom in water and in aqueous solution of poly (ethylene glycol) (1500) at different temperatures (288.15, 293.15, 298.15) k have been used to estimate the apparent molar volume (Vθ), limiting apparent molar volume (Vθ˚) experimental slope (Sv) and the second derivative of limiting partial molar volume [δ2 θ v° /δ T2] p .The viscosity data have been analyzed by means of Jones –Dole equation to obtain coefficient A, and Jones –Dole coefficient B, Free activation energy of activation per mole of solvent, Δμ10* solute, Δμ20* the activation enthalpy ΔH*,and entropy, ΔS*of activation of viscous flow. These results have been discussed in terms of solute –solvent interaction and making/breaking ability of so
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Woman is the first target of social advertising, because most of these advertisements are primarily belong to them. This paper which is entitled "Social Responsibility for the Employment of Woman in Sustainable Development Declarations, An Analytical Study of Road Advertising in Baghdad" focuses on the use of woman in advertising. This aspect shows that some people see that advertisement is a mirror to what’s found in society such as woman’s behaviors in her everyday life and so on, while other people see that as long as the public wants those advertisings, they are free to choose what they prefer. They think that the shameful advertisements are natural and unavoidable. These vie |
Thermal performance of closed wet cooling tower has been investigated experimentally and theoretically
in this work. The theoretical model based on heat and mass transfer equations and heat and mass transfer balance equations which are established for steady state case. A new small indirect cooling tower was used for conducting experiments. The cooling capacity of cooling tower is 1 kW for an inlet water temperature of 38oC, a water mass velocity 2.3 kg/m2.s and an air wet bulb temperature of 26oC. This study investigates the relationship between saturation efficiency, cooling capacity and coefficient of performance of closed wet cooling tower versus different operating parameters such wet-bulb temperature, variable air-spray water fl
ABSTRACT Background: Color changes that are detectable to human eye can affect the esthetic appearance of ceramic veneers. The purpose of this study was to evaluate and compare the effect of artificial accelerated aging on the color of ceramic veneers cemented with different resin cements. Materials and Methods: Sixty discs were prepared with 0.5 mm thickness, 30 discs made from IPS e.max press (Ivoclar Vivadent) and 30 discs were made from VITA Enamic (VITA Zahnfabrik). The discs were cemented with three resin cements: Variolink Veneer MV 0 shade (Ivoclar Vivadent), Rely X veneer Translucent shade (3M ESPE) and NX3 Nexus Clear shade (Kerr Corporation) with 0.1 mm thickness. The spectrophotometer Easyshade Advance was used to measure the co
... Show MoreRailway right-of-ways, traditionally reserved for transportation, present significant potential for development as environmental and recreational spaces, particularly in urban areas. In the Municipality of Dora, the active railway line is crucial to the region's transportation network, yet the adjacent lands remain underutilized and could be transformed into spaces that benefit the community. The key challenge lies in balancing the operational integrity of the railway with the local community’s aspirations for green and recreational developments. This study aims to assess the preferences of local residents and key decision-makers regarding the potential development of the railway right-of-way in Dora. The goal is to propose sustainable so
... Show MoreThe research dealt with the study of choice between a range of different words between the repetitive texts in the verses of the Koran and explain the reason behind this choice, and how the context has the greatest impact in this choice, and that each word in the Koran was placed in the most appropriate place, which can not be replaced by equivalent words, whatever The degree of similarity between them in the indication of the other because it remains at the end that each of those vocabulary synonyms are indicative, the first of them especially that makes the possibility of replacing them with the equivalent vocabulary impossible, and the second general significance and this connotation makes them share with their peers In one aspect of
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