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.
ان الاستثمار في راس المال البشري االمتمثل بالقوى العاملة مرتبط بالتنمية المستدامة وان الانسان هو الثروة الحقيقية للأمم. والانفاق على التعليم تكون له انعكاسات ايجابية على الواقع الاقتصادي ووالاجتماعي والسياسي. ومن اجل تحديد العوامل المؤثرة على القوى العاملة تم تحليل العلاقة السببية (كرانجر) بين القوى العاملة و عدد الخريجين والسكان وعدد الجامعات والناتج المحلي الاجمالي والانفاق على االتعليم العالي ، بوجو
... Show MoreGod Almighty singled out Arab nation to carry divine messages، and make them the land of Iraq to store the soil prophets and apostles and grandchildren of Al al-Bayt، peace be upon them as they were and are still a beacon for people، Shrines and monuments and flags، frequented by science students from various walks of life، were are shrines representing the name of Iraq by the private and the nation of Islam in general، sung by the preacher and artist and writer
ملخص الدراسة
سعت الدراسة تعرف اثراستعمال الأنموذج المعملي في تصحيح المفاهيم الرياضية شائعة الخطأ لدى طلاب الصف الأول المتوسط بالإجابة عن السؤال "ما اثر استعمال الأنموذج المعملي في تصحيح المفاهيم الرياضية شائعة الخطأ لدى طلاب الصف الأول المتوسط" ولتحقيق هدف الدراسة وضعت الفرضية الصفرية "لايوجد فرق ذو دلالة إحصائية عند مستوى الدلالة (0.05) بين متوسطي درجات طلاب المجموعة التجريبية الذين يدرسون المادة المقرر
تعيش قارة آسيا حالة فريدة تكاد تقترب من حالة أوروبا قبل الحرب العالمية الثانية، فالقارة حاليا تحتوي على العديد من القوى الإقليمية الفاعلة أبرزها الصين وروسيا والهند واليابان، أما القوى الإقليمية الفاعلة في نطاق نظمها الإقليمية الفرعية نجد من أهمها الكوريتين (الشمالية والجنوبية)، وباكستان، وإيران وغيرها، ووجه الاختلاف عن أوروبا هو أن آسيا منطقة شاسعة جغرافياً، وكل نظام إقليمي فرعي فيها هو نظام قاري بحد ذات
... Show MoreThe importance of the topic lies in explaining the extent of Sheikh Abdul Qadir Al-Kilani’s interest in social and scientific life in Baghdad
ان الحرب الاوكرانية والتصعيد الروسي ضد اوكرانيا يرتبط بصراع جيوسياسي واسع على مناطق القوة والنفوذ والمجالات الحيوية، وتنافس تجاري دولي محتدم على النفط والغاز ومسارات خطوط التجارة الدولية بين اقطاب استراتيجية دولية تتجاوز اوكرانيا، إذ يأتي الصراع ضمن اطار التحولات الدولية الراهنة والصراعات على مناطق القوة والنفوذ الجيوستراتيجي والمكانة الدولية بين القوى الدولية المؤثرة في القضايا والشؤون الدولية، ويبق
... Show MoreCloud Computing is a mass platform to serve high volume data from multi-devices and numerous technologies. Cloud tenants have a high demand to access their data faster without any disruptions. Therefore, cloud providers are struggling to ensure every individual data is secured and always accessible. Hence, an appropriate replication strategy capable of selecting essential data is required in cloud replication environments as the solution. This paper proposed a Crucial File Selection Strategy (CFSS) to address poor response time in a cloud replication environment. A cloud simulator called CloudSim is used to conduct the necessary experiments, and results are presented to evidence the enhancement on replication performance. The obtained an
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This study discussed modern variable in the organizational thought that is the high performance organizations in the two of Iraqi public organizations. The aim of study determines to know the level of the performance in this organizations (high or not). The data was Collected by questionnaire which contain (8) characteristics, the organizational design, strategy, process, technology, leadership, the roles, culture, and external environment). The sample contain from (76) employees;
Results points that the two organizations didn’t reach to the high level of performance, and there are significance's difference among them.