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.
اهتمت المجتمعات العالمية في الآونة الأخير بفئة الأطفال ، ورعاية الطفولة وذلك لما لها من أهمية كبيرة في مستقبل المجتمع ، وتنميتة وتقدمه . لأنها يعتمد عليها في تقدم وتطور المجتمع فـي جميع المجالات الاقتصادية والاجتماعية والثقافية . ومن هنا ارتبطت الطفولة بالحياة برباط عضوي فالأطفال براعم الحياة ومع هذه البراعم تستمر الحياة لذلك اهتمت دول العالم بوضع البرامج وعقد المؤتمرات من اجل النهوض
... Show Moreولد ابو بكر محمد بن زكريا الرازي في الري سنة 250هـ (864م) وتعمق في الطب والكيمياء والفلك والأدب والفلسفة وهو أحد مشاهير الاطباء في زمانه وهذا هو السبب الذي دعاه لأن يتنقل من بلاط الى اَخر , ولم ينعم بالأستقرار في حياته بالنظر الى تقلب الأهواء والاُمراء وأضطراب الأحوال السياسية . قام برحلات كثيرة , وعهدت اليه ادارة بيمارستان ( مصح ومشفى ) الري ثم قام بهذه المهمة نفسها في بغداد.
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... Show MoreThe fact of having Journalism being open to people from different orientations professions, working as journalists requiring protection just to spread corruption, is one of the biggest threats faced by journalism.
Journalists noticed the spread of unprincipled journalists with no journalistic ethics amongst them, they tried to protect their profession from these corrupt outsiders who might annihilate the mighty of journalism. The principles of the journalism profession known as journalistic ethics, are one the most important formulations of the law concluded by the journalists and those concerned by the the profession, they were then published in public in order to prove their professionalism, especially for those who don’t und
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عملية صناعة واتخاذ القرار في السياسة الخارجية للرئيس جورج والكر بوش
وقائع واوراق ندوة (السياسة الخارجية الامريكية في عهد اوباما) التي عقدها فرع الدراسات الدولية في 25 تشرين الثاني 2009
يتناول البحث جزئية من جزئيات موضوع الفسخ المبتسر للعقد
ان مرتكزات السياسة الخارجية العراقية لمرحلة ما بعد العام 2003 قد عكست توجهات ايجابية قادت الى صياغة مجموعة من الرؤى والتصورات الاستراتيجية الجديدة التي افضت الى اعتماد وتوظيف الوسائل والقنوات الدبلوماسية بوصفها وسائل فعالة وبطريقة متكاملة ومتوازنة من اجل تعزيز مستويات الاداء الفعلي وتحقيق جميع الاهداف المستقبلية للسياسة الخارجية العراقية في ضوء صياغة معادلة مفادها: تدعيم وترصين اداء مؤسسات صنع السياسة ال
... Show MoreThis research discussed and analyzed the formulation of a strategy to manage tax compliance risks, as an applied research in the General commission for Taxes. The questionnaire was used as a research tool to identify the factors that stimulate or retard the research sample from being compliant. The K-means clustering method was also used to enable the classification of the research sample's views into four behaviors, some of these views pose tax-compliance risks. The research concluded that risk management is a continuous process and that all departments of the General commission for Taxes are responsible for its implementation to enable them to deal with the behavior of the taxpayer towards tax compliance. And it recommended
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