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 objective of the research is to find the best method to estimate rice crop through out evaluating the applied methods of stratified random sampling .By using different sorts of sampling estimators, a comparison was held among the variances of the mean for simple random sampling, stratified random sampling(var()) and separate regression estimator. The results indicate that the separate regression estimator give best estimations. The approximate cum.f4/5 method was used to determine the optimum stratum boundaries, new strata was put and then var () was calculated .In comparison with strata used nowadays in central statistical organization, the new strata led to obvious decrease in the variance. The stratified mean wa
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Some great families in England had competed for the sake of getting authority and power in England.
This competition turned to be a bloody civil war which extended till 1455 and ended with the victory of Henry Tudor whose judgment in England started from 28th of August 1458, consequently a new dynast which is known as (the Tudor)has established
أن هذه الدراسة هي دراسة نظرية اهتمت بتقديم مدخل معاصر لمنظمات الأعمال، يمكن أن يعتمد علية من أجل تحقيق الريادة و البقاء. وذلك من خلال اعتماد مدخل الهدم الخلاق و تقديم أنموذج قادر على التفاعل مع البيئة بكل ما تقدمه من فرص وتحديات.
وتم تقسيم هذه الدراسة إلى ثلاثة مباحث،تناول المبحث الأول منهجية الدراسة. وبينما تناول المبحث الثاني توضيح مفهوم الهدم الخلاق والعناصر المكونة لهذا المدخل وأخيراً
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Ibn Khaldun is one of the best Arab Muslims scientists who participated in establishing Arabic Muslims heritage in all different disciplines & directions specially in sociology, neurological & his political theories which showed the development of Arabic philosophy in all scientific disciplines specially his introduction
Abook of alzmkchri (AL-Mefsal) considers one of the most book familiarities among grammarians whom begin to explain it importance kitab AL-Takhmair for Khwarizmi separated opinions in grammatical schools that dealt with.
Arabic humanity heritage had considered as a treasure of artistic, literary aspects, which is full of energies to embody investment by suitable historical ideology.
Theatre, art can be used, corresponded to make special essay reflecting a desire to establish cultural notification.
السياسة الداخلية لعراق ما بعد الانتخابات 2010 دراسة في الثوابت والمتغيرات
Action films employ many artistic and literary elements that contribute greatly to building the general meaning of the film and push the wheel of the film forward. The element of mystery and suspense is used as two basic elements in action films. The cinematic language in action films depends on global coding, which is not models as it might be. It is based on logic, rather as units that aspire to morphology and not their homogeneity as the physical sense, but as the logical harmony of interpretive authority and enlightenment and in action films as a field of communication and a field in its origin in which the signifier contrasts with the perceptions of the meaning and in it takes a certain number of units preventing each other and thro
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The historian, Professor Dr. Abdullah Al-Fayyad, left a huge legacy of knowledge product that scholars and stakeholders benefited from in the field of Islamic historical and modern studies,
Arabic humanity heritage had considered as a treasure of artistic, literary aspects, which is full of energies to embody investment by suitable historical ideology.
Theatre, art can be used, corresponded to make special essay reflecting a desire to establish cultural notification.