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.
اصبح لمجالس الادارة في الشركات دوراً حاسماً في تعزيز الحوكمة الفاعلة، كونها تتحمل المسؤولية النهائية عن نظم الرقابة الداخلية في شركاتها، ويلعب التدقيق الداخلي دوراً اساسياً في مساعدة تلك المجالس على القيام بمهمات الحوكمة. ولهذا يبذل مجمع المدققين الداخليين الامريكي جهداً كبيراً في توجيه اعضاءه ليكونوا متخصصين في اصول حوكمة الشركات وتحسين وتقوية اخلاقيات العمل وسلامة المنظمة.
لذا فإن ا
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يعد الزمان عنصراً جمالياً مساهماً له القدرة على خلق المعنى والدلالة ، ومشاركاً في الاستراتيجية الحكائية إذ ينتقل من مجرد عنصر حكائي إلى محرض للمتلقي فهو زمان الإنسان الداخلي .
Ibn Khaldun is one of the best Arab Muslims scientists who participated in establishing Arabic Muslims heritage in all different disciplines & directions specially in sociology, neurological & his political theories which showed the development of Arabic philosophy in all scientific disciplines specially his introduction
السياسة الداخلية لعراق ما بعد الانتخابات 2010 دراسة في الثوابت والمتغيرات
Action films employ many artistic and literary elements that contribute greatly to building the general meaning of the film and push the wheel of the film forward. The element of mystery and suspense is used as two basic elements in action films. The cinematic language in action films depends on global coding, which is not models as it might be. It is based on logic, rather as units that aspire to morphology and not their homogeneity as the physical sense, but as the logical harmony of interpretive authority and enlightenment and in action films as a field of communication and a field in its origin in which the signifier contrasts with the perceptions of the meaning and in it takes a certain number of units preventing each other and thro
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The historian, Professor Dr. Abdullah Al-Fayyad, left a huge legacy of knowledge product that scholars and stakeholders benefited from in the field of Islamic historical and modern studies,
There are many varied studies that dealt with the dramatic construction, especially books and studies that addressed drama in its construction and the method of writing it, that no textbook or a general cultural content is void of tackling the dramatic text in its construction and how the dramatic action develops in it. Therefore, a question occurs to the mind about the feasibility of dealing with the dramatic construction in this time, where many contemporary studies of dramatology and its relation and the contemporary critical directions are accumulating. This question many have two realistic aspects, yet the novelty and originality that this research shows lie in addressing a refined linguistic text in its style and connotations, such
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Recent advancement in production technologist of manufacturing processes have left an important effects upon cost structure. Moreover the problem for providing necessary and adequate information for managerial decision making.
Therefore the cost – volume – profit analysis under the new activity based costing has replace the old method for Analysing the relation between C.V.P with respect to profit planning and control.
In brief the C.V.P object is to discuss the effect of changes on profit resulting from changes in sales volume, cost of manufacturing and selling price.
This study consists of four chapters:
The first chapter dea
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Human Rights The word of graduation in the Arabic language to many meanings may be the most appropriate of what Al-Ragheb Al-Isfahani said in the right: is the coming of the thing from saying or doing at the time it must and in the form that must be, so the term human rights includes the following:First: A party has the right and another duty to.