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 internet, unlike other traditional means of communication, has a flexibility to stimulate the user and allows him to develop it. Perhaps, the reason for the superiority of the internet over other traditional means of communication is the possibility of change and transmission from one stage to another in a short period. This means that the internet is able to move from the use to the development of the use and then the development of means and innovation as the innovation of the internet is a logical product of the interaction of the user with the network. The internet invests all the proposals and ideas and does not ignore any even if it is simple. This is represented in social networking sites which in fact reflects personal emotio
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Praise be to God, who is by His Power, righteous is done, and by His help to slaves who He likes, and God bless our Prophet Muhammad envoy mercy to the worlds, and upon his family and the good mates until Doomsday.After:
The fact that cursing is the far distance and expulsion from the mercy of God, curse has been proven by him - peace be upon him - for the many varieties in the Sunnah, with indication of a permit cursing the insurgents from the people of Qibla, either saying - peace be upon him -: (the believer never be as a curser ...), what is meant by those who do not deserve damnation of those not cursed God and His Messenger, and for this we must remove words cursing from the Dictionary of our words following the examp
... Show MoreWireless control networks (WCNs), based on distributed control systems of wireless sensor and actuator networks, integrate four technologies: control, computer network and wireless communications. Electrostatic precipitator (ESP) in cement plants reduces the emissions from rotary kiln by 99.8% approximately. It is an important thing to change the existing systems (wireline) to wireless because of dusty and hazardous environments. In this paper, we designed a wireless control system for ESP using Truetime 2 beta 6 simulator, depending on the mathematical model that have been built using identification toolbox of Matlab v7.1.1. We also study the effect ofusing wireless network on performance and stability of the closed l
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لا يستطيع كل كائن حي أو كيان اجتماعي أداء دوره الذي يفترض أن يقوم به ما لم يمتلك الوسائل الكافية والضرورية لأداء ذلك الدور قال سبحانه وتعالى ((قال ربنا الذي أعطى كل شيء خلقه ثم هدى – طه 50)).
والنشاط الاقتصادي كجزء من الكيان الكلي للمجتمع لا يختلف عن هذه القاعدة، إذ عندما يراد من النظام الاقتصادي أداء دور فاعل فلا غنى له عن الوسائل التي تمكنه من أداء دوره المنشود. للنظام الاقتصادي مجمو
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يستهدف البحث الحالي تعرف مستوى الذكاء الناجح لدى الطلبة في مدارس المتفوقين في المرحلة اإلعدادية، وكذلك تعرف مستوى الذكاء الناجح حسب متغير الجنس )ذكور، إناث(، فضالً عن تعرف لمتغير السيطرة الدماغية لدى الطلبة في مدارس المتفوقين، وتعرف السيطرة الدماغية وفقا الجنس )ذكور، ً إناث(، باإلضافة إلى تعرف العالقة بين متغير الذكاء الناجح والسيطرة الدماغية، وتم اختيار عينة عشوائية طبقية تكونت من )180( طالب وطالبة من مدارس
... Show MoreThe research topic (The dramatic structure transformations in the Iraqi Feature Film) studies the dramatic structure and its transformations in the Iraqi feature film. The research determined the research problem and the need for it in addition to the aims and the limits of the study as well as its importance. The theoretical framework consists of the following themes: the dramatic transformations mechanism and dramatic data in the Iraq film 1957-2003 then the dramatic values transformations and the performance contradictions in the Iraqi film.
The research, after concluding the theoretical framework, came up with a number of indicators of the theoretical framework that have been used as a tool to analyze the sample. The research proc
تتفق الدراسات الحديثة على ان النظام الديمقراطي في بلد ما لايمكن ان يقام الا في ظل جو تسوده الحرية السياسية والدينية، الا ان مصطلح الديمقراطية ومصطلح الحرية وضُعا في دائرة جدلية، لان مفهومهما بقي متعدداً ومختلفا فيه. يعد كارل بوبر من ابرز الفلاسفة في الفكر السياسي الغربي المعاصر المدافعين عن الديمقراطية بوصفها النقيض للديكتاتورية، إذ حدد وظيفتها بقدرتها على كبح جماح النخبة الحاكمة واخضاعها للقانون لمنع نزو
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