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.
الغلط في القانون الانجليزي على انواع ثلاثة (غلط مشترك Common mistake ) يقع فيه الطرفان مع علم كل منهما بنية الآخر ويقبلها دون ان يشوب الاتفاق نقص او يعتريه تحفظ ، و(غلط من الجانبين Mutual mistake) يكون كل متعاقد واقعا في غلط فيما يتعلق بما قصده الآخر، فيقدم كل منهما عرضاً مخالفاً للآخر و(غلط من جانب واحدUnliteral mistake ) يقع فيه احد المتعاقدين فقط ويكون المتعاقد الآخر اما عالماً بالغلط او يفترض انه عالم به . فإذا دفع احد المتعاقدين
... Show MoreThe calamities, calamities, problems and constant dilemmas that society is experiencing have made it the responsibility of professors and researchers to find appropriate and effective solutions to these issues, and among those calamities that our societies faced was the problem of the epidemic represented by (Corona-Covid-19)
The message of the Kurdish tag tagged with(Mada alfay fi taqrir lays kamithlih shay) one of his most prominent scientific messages in the door of faith, especially in the matter of the unification of the divine self and its distancing from all analogies and representations and the importance of this message historically, due to its documentation of a stage in the development of Islamic speech thought, where the logical method was taken over the minds of the intellectuals of Islam, including the kurani, whether it is in understanding the quranic and modern meaning or as a way of convincing me towards the opponent.
The Kurd was able to use logical concepts to marginalize the difference between grammarians and interprete
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The main problem of this research titled (the prevailing scientific values in children's programs provided by the channel (mbc3) is the disclosure of the scientific values that are included in the children's program in the mbc3 channel) which are directed to an important group of society, which is the category of children who spend long hours in front of TV screens to watch these programs, and therefore they acquire many values that can replace fixed values, such as social, moral, religious, etc., and the content analysis method has been used to analyze children's programs presented by mbc3 channel), and the research has reached a number of The results can be summarized b To come: |
The research dealt with the study of the element of time in the cinematic language and the role it plays in creating the aesthetic meanings in the documentary film by means of the various structural constructions with which time is constructed. The research included the introduction and the problem of research, which was represented by the following question: (Did the documentary film adopt the values of time formats in the fiction film or it created for itself special linguistic formulations and models which achieve the aesthetic concept?). It also included the importance of research, the need for it and its goal in addition to clarifying the limits of research.The theoretical framework included three sections the first of which is the
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مشكلة البحث
لقد تفاقمت مشكلة تلوث البيئة في السنوات الأخيرة من العقد الأخير والعقد الأول من القرنين العشرين والحادي والعشرين على التوالي بشكل يلفت النظر. إذ انتشر الاستعمال غير العقلاني للموارد الطبيعية من مياه ملوثة وسكن غير صحي وغير ملائم وسؤ التغذية وظروف الصحة العامة الرديئة وانتشار العوادم التي تحدثها المركبات والمولدات التي انتشرت في أحياء المدن العراقية لتزوي
... Show Moreهدف البحث التعرف على الملل الأكاديمي لدى طلبة المرحلة المتوسطة، فضلا عن التعرف على الفروق في الملل الاكاديمي على وفق متغير الجنس ومتغير الصف الدراسي، استخدمت الباحثة المنهج الوصفي، تكونت عينة البحث من ( 200) طالباً وطالبة تم اختيارهم بطريقة عشوائية وبعد تطبيق مقياس الملل الاكاديمي (من اعداد الباحثة) على عينة البحث وباستخدام الوسائل الإحصائية المناسبة توصلت نتائج البحث الى ان: طلبة المرحلة المتوسطة تعاني من ال
... Show Moreالنحت العربي في جنوب شبه الجزيرة العربية (اليمن) قبل الاسلام
أن للتطرف العنيف أسباب متنوعة تقف وراء ظهوره وتمدده في دول العالم المختلفة على نطاق واسع، إذ إن لكل بيئة ظروفها وخصوصياتها الكلية والفرعية التي تسهم في تعزيز القدرة التأثيرية للسلوكيات العنفية في إطار مجتمع ما، لاسيما إذا علمنا إن التطرف العنيف المؤدي الى الإرهاب كسلوكيات عنفية متطرفة مدمرة للبناء المجتمعي ما كان ليستمر لولا وجود بيئة حاضنة وظروف تساعد في انتشاره واستمرارية قدراته التأثيرية في البناء السي
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