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.
على وفق ستراتيجية توظيف الامكانيات الاسلوبية والفنية والجمالية للحوار بنوعيه( الحوار الداخلي ) و( الحوار الخارجي ) استطاعت الكاتبة ان تمنح روايتها ( ذاكرة الجسد ) خصوصيتها الادبية .فعلى مستوى الوظيفة البنائية اسهم الحوار في التشكيل الزمني لبناء الرواية ،وتقديم الشخصية ،وبناء الحدث وتطويره .وعلى المستوى الاسلوبي نجد أن الحوار تجاوز وظيفته الاخبارية الى وظيفة التأثير في المتلقي من خلال الافادة من معطيات المسر
... Show Moreيعد تعزيز التجارة الدولية في مقدمة اهتمامات اي دولة ، فكل دولة تسعى الى تقديم خدمة مشروعات لتنمية الخدمات والبنى التحتية بوسائل عدة ، ومن اهمها قيامها بتمويل تجارتها الداخلية والخارجية مما يؤدي الى ازدهار وتحقيق التنمية والنمو المستدامين في تلك الدولة . ولكي تؤدي التجارة الدولية دوراً بارزاً في تحقيق النمو والتنمية المستدامين، لابد من توافر بيئة تجارية دولية مناسبة و نظام تجاري دولي مساند لعملية التنمية فا
... Show Moreتعدُّ القارة الإفريقية ذات موقع جيوسياسي إذ إنه يربط دول العالم بعضها ببعض، وأنّها تحتوي على ثلث الاحتياط النفطي المؤكد العالمي واليوريانيوم والمعادن الأخرى مما جعلها ذات أهمية للدول العظمى، وأنّها غير مستقرة سياسياً إذ تكثر بها النزعات والهجمات الإرهابية مما جعل الدول العظمى تتسابق لوقف المشاكل، ومن أهم هذه الدول العظمى هي فرنسا التي تحتفظ بنفوذها السبق أي الاستعماري في القارة وأنّها لا تتنازل عنه لأي دو
... Show Moreيعد الذكاء الاصطناعي من العلوم الحديثة التي ارتبطت بالإنسان منذ العقود الخمسة الماضية، ولتصبح السياسة الرقمية الاقتصادية جزءاً لا يتجزأ من المجتمع، لكونها خرقت أغلب مجالات حياة الانسان. وهذا ما شجع صانعوا السياسات التكنولوجية الجديدة في التفكير بكيفية توظيفه لخدمة مصالحهم الاقتصادية العُليا، بغض النظر عن بذل الجهود للتفكير في مصالح الانسان الاقتصادية وتنظيمهم ومراقبة الذكاء الاصطناعي التوليدي. لقد أيقن
... Show MoreThis Kind of study has a special importance. Great numbers of Arab Muslims share a lot of their work, their Trans lations & new additions to scientific heritage. They facilitate the indirect way for Europeans to got Greek scientific knowledge. Ibn Sina classified & collected in his book (Law) Galen`s medical publications & he clarified, arranged & make them easy to understand.
Targeted research to study variations formalism in the paintings of the scratch -linear , and through surveys carried out by the researcher , found and to his knowledge that the study did not address the researchers before, this researcher found rationale in the study of plates scratch and identify variations of design in it. , Which included the first chapter of the research problem in question the following: What morphological variations in the paintings of the scratch -linear ?In order to reach solutions to this problem and to achieve results so research aims to identify the characteristics of the scratch for paintings , and design fundamentals and relationships , which are identified by the researcher Balentajat completed in all of I
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Through the history of art movements, abstraction has been rotating between appearance and disappearance, mounting and stillness while its performances differed between reduction and simplification on the one hand and between the use of chromatographic and linear abstraction on the other. As a result, to what is mentioned, abstraction has appeared in many different artistic forms underlying the systematicity of the plastic art history.However, according to a contemporary point of view that comes up with the scientific revolution, the art of optical deceiving (illusion) appeared to find a hybrid art form that locates between the geometricity of abstraction and the scientific, visual and psychological foundations that are linked with the i
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The organization and development of the irrigation system and agrarian reform in Iraq had an impact on the diversity of its methods and uses.
The shortcomings of the Muslim regime were however, became more obvious in later periods. Under the first Abbasids, the Muslims bourgeoisies were still a new class, rising in the social hierarchy of the caliph empire. It became even powerful class and a factor to reckon with