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.
The origin of this technique lies in the analysis of François Kenai (1694-1774), the leader of the School of Naturalists, presented in Tableau Economique. This method was developed by Karl Marx in his analysis of the Departmental Relationships and the nature of these relations in the models of " "He said. The current picture of this type of economic analysis is credited to the Russian economist Vasily Leontif. This analytical model is commonly used in developing economic plans in developing countries (p. 1, p. 86). There are several types of input and output models, such as static model, mobile model, regional models, and so on. However, this research will be confined to the open-ended model, which found areas in practical application.
... Show Moreهذه الورقة البحثية تهدف الى مناقشة سبل تطوير التعليم العالي في العالم العربي والارتقاء به لخلق راسمال بشري وثقافي قادر على مواجهة تحديات العصر، فالتنمية الاقتصادية في العصر الحالي ما عادت تعتمد على المواد الاولية بل على القيمة الابداعية للانسان التي اصبحت اساسية في المنافسة الحالية بين الشعوب الانسانية و اصبح الفكر المبدع هو المنافس الحقيقي المهم حيث تصنع احدث الاجهزة الحديثة باحجام صغيرة ومواد اولية اقل
... Show MoreThe literary aspect of any text reveals when it used The inspiration language
which reveals the creative aspect of language for the creator (writer) he in turn
will seek for the best choice from these aspects then, he will distribute them due
to their intention, and according to the their context
Thus, propagandistic text contains many moral features which the language
accord to thus , we found that the morning (dua al asbah)is full of creative
literary manifestations through many abstentions which happened in different
structures that contain the text, especially in structure of metaphor, and contrast.
we found many outstanding gaps and abstentions in these are given life, matter
that gives the text the most l
Performance measurement is considered one of the most important issues in
Measuring performance effectiveness in the educational institutions by maintaining balance among quantity measurable factors. They can be financial or non‐financial factors. Consequently they reflect decisive factors in the success of educational institutions and determining suitable standards and dimensions for their activities and giving it proportional importance. Adopting the idea of Balanced Score Card as one of the modern administrative techniques and methods by educational institutions assists in the development of administrative work, adjusting the performance in addition to achieving comprehensive standard and development of educational universit
... Show More
The poetic necessity in evidence to explain Ibn Aqeel were not alike, came a statement from him as a necessity in some verses and the other came as abnormal, differentiating it from the language, but he never mentioned in some verses in which the need as a necessity,
This research aims to reveal the impact of applying a teaching course in
gaining and preserving information by female students comparing with the
traditional method, through testing the two following hypotheses:
1. There is no difference with statistical significance at the level of
significance (0.05) between the average grades achieved by the
experimental group of female students taught using a teaching course,
and the control group of female students taught using the traditional
method.
2. There is no difference with statistical significance at the level of
significance (0.05) between the average grades achieved by the
experimental group of female students taught using a teaching course,
and the contro
يرسم الشاعر صورة بالكلمات، ومتى ما تتابعت الصور صارت تمثل لوحة شعرية على قدر كبير من الفنية والابداع, وقد أكثر ديك الجن في شعره من هذه اللوحات ويلاحظ القارئ أن الرمز يعمل عملا مهما في تشكيل اللوحة، وظهرت أنواع متعددة من اللوحات منها اللوحة الرثائية, والغزلية, ومن الرموز التي وظفها ديك الجن رمز الظبي, رمز الديك, واستعمل رمز القبر وظهرت لوحات متنوعة في شعره، ومنها اللوحة الخمرية التي تجعل للخمرة احساسا ومشاعر وا
... Show Moreالانسحاب الاجتماعي بغض النظر عن العوامل المسببة له قابل للعلاج حيث وضحت البحوث العلمية إمكانية الحد منه باستخدام أساليب تعديل السلوك .
وهو نمط سلوكي شائع لدى معظم الفئات ان لم يكن كل فئات الاعاقة ،وينتج هذا النمط السلوكي الانسحاب الاجتماعي عن عوامل عدة فاذا الطفل يعاني من تلف في الجهاز العصبي المركزي فان هذا التلف قد يحول دون قيام الطفل بالنشاطات المطلوبة للعلاج. توضح البحوث العلمية ام
... Show Moreتعد الدولة الموحدية من اغلب دول العالم الاسلامي تميزا من حيث المذهب والايدلوجيا والنظام السياسي
It was the most important weapons that were used during the long cultural war standing against Islam, it is interesting colonists Muslim women special attention, and directed to lure women rebellion against religion, and go out on their own teachings in this religion,