Laser etching may be an alternative to acid etching of enamel and dentin. Several characteristics of irradiated dental hard tissues have been considered advantageous, microscopically rough surfaces without demineralization, open dentinal tubules without smear layer production and dentin surface sterilization. The aim of this study is to determine and compare histology the microleakage in class V cavity restored with a light cured composite after conditioning the samples(tooth surface) with 1-acid etching, 2-Q-switched Nd:YAG Laser etching and finally 3- acid and laser etching. Materials and methods: Twenty four non carious human extracted teeth were used in this study. The samples were equally grouped into four groups of six teeth each. A class V cavity was prepared. In group I, tooth surface was etched with a 37% phosphoric acid gel. In group II, the tooth surface was conditioned using a pulsed Nd:YAG Laser alone with a wavelength of 532 nm. The parameters were of pulse energy 60 mJ, pulse repetition rate 6Hz and energy density was 0.48 J/cm2. In group III, the tooth surface was treated with Nd: YAG Laser and then was etched with phosphoric acid. In group IV, the surface was treated with 37% phosphoric acid then irradiated with Nd: YAG Laser; with the same parameters and concentration mentioned in group I and II. The samples immersed in 1% basic fuschin dye to mimic the normal stains in oral cavity and the sections were examined by a stereomicroscope and the readings were scored. Results: The results showed that group IV, in which the surface was treated with 37% phosphoric acid and then irradiated with Nd: YAG Laser) recorded the least microleakage of the four groups, where group III, in which the tooth surface was treated with Nd: YAG Laser and then was etched with phosphoric acid)recorded reasonable results better than group I (group I tooth surface was etched with a 37% phosphoric acid gel) or group II , in which the tooth surface was conditioned using a pulsed Nd:YAG Laser alone) Conclusion: The use of Q-switched Nd:YAG laser in etching the tooth surface was so effective that it can be used in treating or conditioning the tooth surface to enhance bonding and the best parameters among the tested samples were pulse energy of 60mJ, pulse repetition rate of 6Hz and energy density 0.48 J/cm2.
תקציר
הילדות נחשבה השלב חשוב בתולדות האדם, וגם המשפיע ביותר בהיווצרות של אישיותו, משום שבו תתהווה את הליבה של ציוני דרך אישיותו של האדם, ויתגבש בו את ציוני דרכו ותכונותו שלו, וגם תשרטט את הבסיס העיקרי של מה יהיה האדם בעתיד. היות והילדות נשארה היא והשלכותיה בקרבו של האדם, עם זכרונותיה היפות והעצובים כאחד, במחקר זה עסקנו בילדותו של הסופר עמוס עוז כסיסמה לפענוח לדמותו, ולספרותו, כמו כן לכאבים שהעברו
... Show MoreThe Negro minority in the United States is associated with social injustice,
political deprivation, and economic oppresion. Its members felt that they are
second-class citizens, and that the acceptance of such status will lead to the
continual oppresion of the Whites upon them. As a result, the educated community
adopted a process to put a framework to their opposition to the former's injustice.
This organised framework is exemplified in the "Niagara Movement," which is
regarded as the first national organisation for Negros. The topic of this study is
chosen due to its historical and political significance.
The study consists of an introduction and five sections. The first section
addresses the preliminaries an
تزايد اهتمام الحكومات باختلاف أنظمة الحكم فيها والأفكار السياسية التي تؤمن بها، بالضرائب كأحد أدوات السياسة المالية، تسعى إلى أن تحقق من خلالها أهداف اقتصادية واجتماعية وسياسية فضلا" عن الأهداف المالية، إذ إن السياسة الضريبية تصاغ أهدافها باتساق وانسجام مع أهداف السياسة الاقتصادية بشكل عام، و إنما كانت الضريبة عام، ولما كانت الضريبة على هذا القدر من الأهمية فانه لم يكن مستبعدا" أن تحظى بعناية مشرعي ا
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Barium–doped TiO2 / n-Si photodetector was fabricated by spray pyrolysis exhibited visible enhancement responsivity profile with peak response at 600 nm flat response between 650 and 900 nm. The quantum efficiency was 30% and specific detectivity was 5x1012 W-1Hz1/2cm at peak response. The GaAlAs laser diode was used to estimate the rise time of the detector.
Quality function deployment tool is trying to improve health services through this study that will be applied in health sector environment , and be based on applying quality function deployment tool (QFD) TO preferable evaluation of main patients requirements in order to determine the technical requirements that need most attention across improving and developing health services .
Main requirements are determined to patients lying in the hospital (under research) which is (educational Baghdad \ medicine city office) in Baghdad, and other technical requirements through pers
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The problem of the present study lies in the challenges that college education especially that concerns the quality of college teachers performance and developing the level of educational process quality.
This study aimed at constructing a vision the researchers have constructed depending on the standards of performance quality represented by Deming's quality course. The researchers presented a number of skills that should be existed in the performance of college teacher through using the analytic and constructing approach in imagining this drawing to develop performance.
The study results represented by a number of efficiencies that college teachers shoul
... Show MoreDespite the global economic downturn, online e-commerce, especially the sale of counterfeit goods, continues to witness a rise in sales, and one of the important players in e-commerce is the owners of e-commerce auction sites. Although they do not have a direct role in trademark infringement, they still consider them indirectly responsible (secondary liability) for infringing on their trademarks. Thus, many cases have been filed by the owners of the original trademarks (which have been infringed by persons who have sold some of the goods and products that are imitating their marks through some electronic auctions) against the owners of those auctions. In view of the international character of the Internet, in different countries, and despit
... Show Moreشكلت السيطرة العثمانية على العراق حقبة تاريخية مهمة ، حيث وضعت فيها ركائز عدد كبير من الأنظمة الأدارية فغدت الأساس للتنظيمات فيما بعد ومنها الإجراءات الإدارية والقانونية وسبل معالجتها لآزمة الأراضي في بغداد1938-1932.