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.
دف البحث إلى قياس الشخصية الاستغلالية لدى طلبة الجامعة على وفق متغيرات: الجنس والتخصص والمرحلة الدراسية ، تكونت عينة البحث من (200) طالباً وطالبة من طلبة جامعة بغداد، قامت الباحثة ببناء مقياس الشخصية الاستغلالية وبعد تطبيقه على العينة وتحليل البيانات بالوسائل الاحصائية المناسبة ، اظهرت نتائج البحث عن شيوع الشخصية الاستغلالية لدى الطلبة ، وان الذكور لديهم شخصية استغلالية اكثر موازنة بالاناث كما اظهرت نتائج ا
... Show Moreالامم المتحدة وقضايا التنمية في العالم الثالث
The wisdom of the Creator ensures the call of every prophet with a miracle that would be something beyond what is familiar from the customs.the prophet Mohammad (pbuh)whose miracle was the Qur’an in a clear Arabic tongue
Sufi architecture (gorges, bands, and zawiyas) played an important
role in the development of Islamic civilization, especially since these
buildings are used as centers of religious education and Sufism, where
people are taught the basic principles of Islam, the biography of the
Prophet, and Sufism.
The main target of this paper is to determine the optimum time for preventive maintenance on machines. Tow methods has been implemented estimating the optimum time duration for preventive maintenance . the first techniques use scheduling depending on data concerning the machine maintenance cost and halted cost from the production reach to the optimum time for maintenance which reflect the minimum cost. Where as the second techniques depends on reability function to estimate the optimum duration time which reflect the minimum cost. The tow techniques above by which we count on in fixing the preventive maintenance both give same result . we also prove that the scheduling method best than the reability function .
يهدف هذا البحث إلي معرفة معنى اللغة وتجلياتها في نتاجات الاديب الإسرائيلي الأكثر جدلا في القرن العشرين، إلا وهو الاديب "موشيه سيملانسكي". فقد طغت صورة العربي في الكثير من أعماله الأدبية وتبوات مكانا واضحا، وكانت النظرة تجاهه، نظرة واضحة أيضا، فصورته لم تتغير بتغير الظروف والاتفاقيات، بشكل يتناسب وهذه الظروف، وإنما بقيت تراوح مكانها، ولم تتبدل بنظرة احترام على الأقل، بل على العكس من ذلك، فهناك بعض المطالبات
... Show MoreThis research aims to shed light on some phonetic linguistic terms used in the Arabic phonetic lesson for the purpose of monitoring, analyzing and tracking its developments. Such a step helps to standardize and weigh between them. The study follows a descriptive-analytical approach; it surveys the problem of the phonetic linguistic term, and its linguistic exactness. Then, it examines some phonetic terms in the Arabic phonetic lesson, such as phonology and phonology; intensity, looseness and mediation; the production, articulatory, transition, position, and the two vocal chords. One of the most prominent conclusions of the study is that the phonetic linguistic terminology enjoyed a tangible development since its infancy, given that phone
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هدف البحث الحالي الى التعرف على اثر استراتيجية الياءات الخمس في التميه مهارة الاشغال المعدنية ، وتبلورت مشكلة البحث عن السؤال الاتي هل يوجد دور لاستراتيجية الياءات الخمس في تنمية مهارة الاشغال المعدنية لدى طلبة كلية التربية الاساسية ، عينة البحث شملت 60 طالب، اما الاستنتاجات التي توصل اليها البحث - تسهم استراتيجية في زيادة الدافعية نحو التعلم , لما توفره فيه من الجو التفاعلي الذي كسر الجمود مما انعكس ايجابياً
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