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 specialist researcher fined the relations between economic ideas with economic facts in his theory which called humanity building it is appeared clearly ( in Ibn Khalduons’ Muqaddimah) in a clothe of economic social phenomenon's as a systematical analysis in all fifty chapters of al Muqaddimah ,therefore this paper deal with Ibn Khalduon economic thoughts as important says which describe the society building in its economic subjective and examine the relationship between The dissert and the city within economic says which are cover the social analysis ,and determinate the analysis objects which clearly in this dualism model ,between the state and economic bas
... Show More
چكيده
نماد در لغت معنى كه (اشاره ،رمز) ودر معنى ديگر مجموعه اى از نشانها، حركتها، حرفها يا كلمه هاى از پيش تعيين شده براى برقرارى رابطه يا مبادلهء پيام است. نماد در قران نيز در سورهء ال عمران آمده است: (قَالَ رَبِّ اجْعَل لِّي آيَةً ۖ قَالَ آيَتُكَ أَلَّا تُكَلِّمَ النَّاسَ ثَلَاثَةَ أَيَّامٍ إِلَّا رَمْزًا ۗ وَاذْكُر رَّبَّكَ كَثِيرًا وَسَبِّح
... Show MoreThe Spanish King Alfonso X could deliver mane Andalusia culture to Europe, but it is the subject of our research, we decided to give a brief overview of his life.
This king March was politically different from the rest of the Spanish kings, which is opening up to the literature and Eastern thought, it is the.
Books of plans are a type of writing in Islamic history , its a type of work whose authors have strived to serve as a comprehensive historical encyclopedia, and they focused most of their attention on highlighting the various aspects of the history of Egypt. , Especially. urban side. And political, military, scientific, social , economic events.
they authors in this Type were not satisfied with that only, but they mentioned the stages of the development of architecture and what followed until their time
الديمقراطية في الفكر الاسلامي المعاصر وعلاقتها بنظرية الشورى
The essential objective of this study presents a analyzes of the combination of reality and fantasy in three dramas of Spanish author Alejandro Casona. "Trees die standing" (premiered in Buenos Aires in 1949), “Prohibited suicide in spring” (premiered in Mexico in 1937) and "The boat without fisherman" (premiered in Buenos Aires in 1945).
The first part is an introduction about the biography of Spanish author Alejandro Casona that will allow us to understand some peculiarities of his work in relation to the social historical context of his time.
In the second part of this study we have analyzed elements of reality and fantasy in the th
... Show MoreAL Sheikh Abdul Qadir Al Gilani is one of the famous Mysticists (sufi). He was known in his literary eloquent and rhetoric speeches. These speeches was cover both the poetry and prose. Also it was in the fields of preaching, soliloquy and maqamat.
دور وزارة الخارجية الامريكية في عملية صنع القرار
ليست الادارة المحلية أو نظام الحكم المحلي ابتكاراُ حديثاً للانسان، بل أنه لازم البشرية منذ أقدم العصور وحتى الآن، إذ الملاجظ أن القرى الصغيرة نشأت قبل أن تنشئ الدولة أو قيل أن يتبلور مفهوم الدولة في الوقت الحاضر وكانت القرى والمدن تجتمع بين حين وأخر- اجتماع أفرادها- لادارة شؤونهم وحل مشاكلهم، وكان هذا خير دليل لتطبيق مفهوم الديمقراطية المباشرة بين أفراد المجتمع الواحد، ولذلك فإن الحك
... Show More
مشكلة البحث:- تواجه المجتمعات العربية في المرحلة الراهنة ,تحديات كبيرة تستهدف الشاب العربي ،والتأثير عليه في الجوانب الاجتماعية والتربوية والثقافية والاقتصادية والأمنية والسياسية ولغض تسليط الأضواء على هذه الجوانب ولاسيما الجانب الاجتماعي،من هنا تبرز مشكلة البحث الحالي في التعرف على توقعات الشباب العربي لمشكلاتهم الاجتماعية في المرحلة الراهنة .
أهمية البحث:-
... Show More