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.
رمت الدراسة التعرف بمستويات التفكير الهندسي لدى طلبة قسم الرياضيات في كلية التربية / ابن الهيثم - جامعة بغداد، ولتحقيق هدف الدراسة تم اعتماد مقياس الحربي(2003) المعد على البيئة السعودية ويتكون من (25) فقرة موزعه على خمسة مستويات وهي (المستوى البصري ، التحليلي ، شبه الاستدلالي، الاستدلالي، المجرد وبلغت عينة الدراسة (206) طلاب من طلبة قسم الرياضيات في كلية التربية- ابن الهيثم بجامعة بغداد تم اختيارهم بالطريقة ال
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Insurance companies play a dual and vital role in the economy in which they operate in two directions. The first is to protect investments from the various risks that threaten them by paying compensation in the event of one of these risks, which prevents companies from leaving the economic cycle and achieving social benefit because of continuity of the company means continuity The payment of taxes to the state and the payment of salaries and wages to employees and employees, in addition to the economic ties in front and background, which integrate the company with other companies (that stop the company can lead to the cessation of other companies), the second trend is that the trap The insurance company obtains the amounts of insurance p
... Show Moreالمقدمة
تمثل الأسعار تعبيرا" نقدياً لقيمة السلع والخدمات المقدمة للزبون، وتعد عملية التسعير من العمليات المهمة وذات الأثر البالغ على نجاح واستمرار منظمات الأعمال، نظراً لما لها من تأثير على المقدرة الربحية وإعادة توزيع الدخل القومي المخصص للاستهلاك، إذ أنه بتحديد الأسعار يستطيع الفرد أن يوزع دخله بين ما يعده ضرورياً من السلع وما يعد كمالياً.
وعموماً فإن لعملية التسعير م
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That God Almighty coast with good things to eat and permitted smug, which did not like Muharram, and the Almighty said: Eat well and do good.
The Prophet peace be upon him if making him some of his friends food and preen it on as it was their situation at the time and then called him an answer to that, and most people prefer to eat and drink on the other other sanctuary Kalmbus and the audio and others
اقيمت الكنائس على جانبي مدينة بغداد الغربي(الكرخ) والشرقي(الرصافة)، أما الأديرة فقد انشئت في موضع مدينة بغداد قبل بنائها وبعد البناء حافظ البعض منها على مكانته وانشئ البعض الآخر، في جانبيها الغربي(الكرخ) والشرقي(الرصافة)، وهو ما سنركز عليه في بحثنا عن كنائس وأديرة بغداد لمختلف الطوائف المسيحية فيها، فضلاً عن تسليط الضوء على دورها الإجتماعي والإقتصادي والثقافي، وإن كان محدوداً جداً وقاصراً على الأديرة أكثر
... Show MoreThis research aims to investigate the impact of a training program for teachers of chemistry according to the strategies for both sides of the brain together in academic achievement for their students, the sample consisted of a 12 teachers of both genders who are teaching chemistry for the students of the fifth scientific secondary schools of the General Directorate for the Education in Garmiyan/Sulaymaniyah governorate, Iraqi Kurdistan region, where five teachers of them randomly selected to involve the training program, and seven teachers did not participate in the proposed training program, where a sample of students was selected for each group of teachers about 147 male and female students for teachers of the experiment
... Show MoreMagical realism potential bulwark plastic art and literature، and won great fame and Research cash innumerable، and like other currents of literary found his outlet in the art of cinema، quoted cinema of literature magical realism and influenced his concepts، and Arab cinema، it was necessary to have a vulnerability to stream، either Tools employing magical realism، unintentionally since the early beginnings dating back to the time of World Wars I and II، or in deliberate more mature in the twenty-first century، due to the emergence of film-makers more aware and culture، and more friction global currents.
But this raises a number of problems that need to be addressed from the maker of
The current study aims at investigating the effect of cooperative learning (Jigsaw) on motivation of female students. Department of kindergarten to learn Human biology. This is of be dove through verification of the hypothesis that there is no significant difference at the 0.05 level between the motivation of experiment of group subjects who study according to (Jigsaw) cooperative learning and that of the control group subjects who study traditionally.
The study is limited to female students al the first year-Department of kindergarten college of Education for women university of Baghdad during the academic year 2007-2008.
An experiment of design of partial control and post-test for two groups is used. The experiment groups consist
God 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