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.
يهدف هذا البحث الموسوم بـ (المنهج النقدي في كتاب الرجال للنجاشي(ت 450هـ )إلى تسليط الضوء على حياة النجاشي ومكانته العلمية والكشف عن منهجه النقدي في كتابه المذكور.
The current research aims to provide a conceptual and applied frame on the subject of multi- level analysis in the research of business administration. The research tries to address some of the problems that befall the preparation of research and studies at the Arab level and local level, where the unity of theory and measurement and analysis, as well as clarify the various types of conceptual constructs and give researchers the ability to distinguish different models related to the level of analysis. On the other hand, this research provides an example of
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Books of plans are a type of writing in Islamic history , its a type of work whose authors have strived to serve as a comprehensive historical encyclopedia, and they focused most of their attention on highlighting the various aspects of the history of Egypt. , Especially. urban side. And political, military, scientific, social , economic events.
they authors in this Type were not satisfied with that only, but they mentioned the stages of the development of architecture and what followed until their time
الديمقراطية في الفكر الاسلامي المعاصر وعلاقتها بنظرية الشورى
The essential objective of this study presents a analyzes of the combination of reality and fantasy in three dramas of Spanish author Alejandro Casona. "Trees die standing" (premiered in Buenos Aires in 1949), “Prohibited suicide in spring” (premiered in Mexico in 1937) and "The boat without fisherman" (premiered in Buenos Aires in 1945).
The first part is an introduction about the biography of Spanish author Alejandro Casona that will allow us to understand some peculiarities of his work in relation to the social historical context of his time.
In the second part of this study we have analyzed elements of reality and fantasy in the th
... Show MoreThe intellectual and revolutionary movements that have emerged since the beginning of the second half of the first century of the Islamic era did not appear suddenly, but must have preceded by a social consciousness, multi-forms, in the forefront of class awareness and religious awareness, and awareness was more painful, Of the society of the Arabian Peninsula - before Islam - feel it and suffer from it, a sense of injustice and tyranny, oppression and humiliation, and the destruction of dignity as well as poverty and hunger, and the injustice of tribal laws, and tyranny of each other and the tyranny of their heads on the tribes members and families belonging to this tribe or hill
الامن الجماعي في اسيا .. بقلم : لونيك فرو وار
The followers of philosophical lesson in Iraq discover steps and important stages through which the country had passed in , since the control of this thought in Arab Islamic civilization until recent time as well as touch the important changes that had happened on it
Islam has paid great deal of attention to land issue where has been
considered most resources for providing Muslims with water and food and
building on that we notice that the Islamic government worked hardly to give
attention ton the land especially newly included under control of Muslims
especially that they had got with out fighting or bloodshed but had been
included via reconciliation with the landlords so the Muslims had share in that
would be taken either in cash or in materials in a value would be differentiated
following several issues like type of harvest and method of watering the land
and religion of the landlords.
So Muslims had listed laws and rules that enable them typical investment
for that l
Much has been written about Baghdad in the history books and documents ,about the Origin of its call , Reality ,history ,peoples ,Rulers and all that have passed since the beginning of creation and so far...