Background: Crown preparation of vital teeth involve the removal of a sound tooth structure, and when enamel removed this lead to exposed dentin with an increase in the number of open dentinal tubules also the diameter of dentinal tubules will increase, furthermore lead to increase movement of fluids inside the tubules all that causes post preparation sensitivity. The aim of this study is to evaluate the effect of desensitizing by Er:Cr:YSGG laser on shear bond strength of prepared tooth and resin cement. Materials and methods: Thirty sound maxillary premolars, grouped into three groups(n=10). Group A is the control group, group B irradiated by Er:Cr:YSGG laser with (0.25 W, 20 Hz, 10%water and air), group C irradiated by Er:Cr:YSGG laser with (0.5 W, 20 Hz, 10% water and air). Results: SEM examination showed complete occlusion of opened dentinal tubules after laser irradiation of both groups that irradiated with laser. Statistical analysis showed significant increase in surface roughness in group B and C. SBS was significantly increase in group B with no significant increase in group C. Conclusion: Er:Cr:YSGG laser can occlude open dentinal tubules without and adverse effect on the retention of the restoration, on the contrary it increase bonding strength. And this increasing was significant in group B with (0.25W, 20 Hz, 10 % water and air). suggestion: so the parameters used in group B (0.25 W, 20Hz, 10 % water and air) is recommended for desensitizing prepared tooth and induce enhancement to the bonding strength of resin to tooth surface.
يتناول هذا البحث اساسيات التعامل بين الرسول الأعظم r وبين المخالفين له في المعتقد، وضرورة التسامح الديني الذي أقره الاسلام وطبقه الرسول الكريم r في حياته، وعلمه لأصحابه الكرام t، وأصناف الناس الذين تعايش معهم الرسول r مدة سيرته العطرة، لاسيما الكفار وأهل الكتاب والمنافقين، مستندا إلى كتب التفسير والحديث النبوي الشريف، وقد جعل الباحث لكل منهم مبحثا مستقلا ، ثم انتهى إلى الخاتمة وأهم التوصيات .
امن الخليج العربي بين الاحتكار الامريكي و رغبة المشاركة الاوربية
The research problem is to determine the nature of the historical relationship between the profession of social work and volunteer work. Consequently, the research aims to investigate the nature of this relationship from a socio-historical perspective. Three axes have been used to analyze this relationship: the role of voluntary work in the development of the social work as a profession, the efforts made by social work to reach professionism and to distinguish it from voluntary work, and the relationship between social work and voluntary work. The research is qualitative analytical research and adopts the Mixed Methods Research (MMR). It identifies some literature for the analysis and implementation of a scoping process. It represents a
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The issue of communication and communication is receiving increasing attention in both contemporary studies and educational literature, and these studies emphasize the importance of studying communication within the classroom, which inevitably applies to the importance of relationships and tensions in the field of teaching art in particular because it is an emotional field that provides an opportunity for communication competencies and skills to be prominent and take Its wide scope, both among the students themselves and between teachers and students. The means of communication are the vessel in which the cultural relations and the commonalities between people revolve. The process of building relationships between students depends in man
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The Islamic civilizational project has become anurgent necessity when Muslims and Arabs faced in recent years, with serious of challenges and the dangers that surrounded them; Globalization is one of these challenges.
Holly Quran and prophetic sunna is the two main sources for this religion and the formers derived the rules from them directly . the jurisprudent was a scientist in commentary of holly Quran , narrators of prophetic Tradition, jurisprudence and linguistics in the same time. The sciences of commentary , jurisprudence , Tradition and linguistics were integral system without any distinguishing until these sciences started to distinguish in their limits and ranges.
This paper examines the gaps in Lebanese building law as well as the exploitation of contractors, stakeholders, and residents in order to make illegal profits at the expense of The Shape of urban agglomerations and their expansion in cities and rural areas, which is contrary to the principles of sustainable land development. It also emphasizes the amplification of the factors of vertical and horizontal building investments in the implementation of buildings contrary to the license, as well as the burden that this places on the city's resulting infrastructure and ability to absorb the activities and needs of its residents. The study then presents recommendations in the process of transformation in the technique of planning and application
... Show MoreTheater is a renewed art until this moment, and it does not stray from its components from life and its spaces in general, but rather is derived from them according to characteristics and directions intended to differ based on finding other, more effective solutions, Therefore, the research entitled (Extractive treatments of the space between tradition and contrast in contemporary theater) consists of four chapters. The first chapter came under the title (the methodological framework). Where he dealt with the research problem and then the importance of the research and the goal of the research as well as the objective, temporal and spatial limits of the research, In addition to defining the terminology and then finding the procedural ter
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