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 research aims at defining the level of the school environment and the social adjustment of the sample due to the sex and the relation among them. The two researchers have stated the school environment scale counting on the theoretical background and previous studies. As for the social adjustment scale, the researchers have used the scale of (Al-Kindy, 2001) and the school environment scale is implicated on (112) students. The schools and the students were elected in a random way. Whereas the social adjustment scale is implicated on (30) teachers in order to know their ratio of the student's adjustment. The results have appeared the satisfaction of the students on the private school environment within their school aspects (the directo
... Show MoreThe expansion of the social media environment has created its own linguistic realities which involve more colloquial communication and practical employment of language. This research focuses on nominalizations in detail, which are originally formed words that have been changed for a noun role. These nominalizations are examined within the context of Facebook posts. The research aims to discover the various nominalizations used and how often they appear in a large sample of data from Public Facebook Posts Corpora. Computational linguistics opened new fields of study and enabled researchers to study large amounts of data easily, making it easier to identify patterns. Two computational methods of identifying nominalization in a large dataset w
... Show More
(126)
(117)
Forward-swept wings were researched and introduced to improve maneuverability, control, and fuel efficiency while reducing drag and they are often used alongside canards, to further enhance their characteristics. In this research, the effects of canard dihedral angles on the wing loading of a forward-swept wing in transonic flow conditions were studied, as the wing loading provides a measure of wing’s efficiency (lift/drag). A generic aircraft model from literatures was selected, simulated, and compared to, using CFD software ANSYS/Fluent where the flow equations were solved to calculate the aerodynamic characteristics. The research was carried at two different Mach numbers, 0.6 and 0.9, for five different canard dihedral angles which tra
... Show More
(1)
(1)
يرمي هذا البحث الى تعرف اثر استراتيجية تعليم الاقران في تصحيح الفهم الخاطئ للمفاهيم الجغرافية لدى طالبات الصف الاول متوسط
التنمية المستدامة حق لكل البشرية وأنها مفهوم ٌ مركب من عنصرين هما التنمية واالستدامة مهمين متالصقين أي ال يوجد تنمية دون استدامة وال العكس يصح، وأنها تمتلك العديد دراسات سياسية وإستراتيجية من األهداف ويبرز هدف الـ)القضاء على الفقر، والقضاء على الجوع( ومن أهم أهدافها، هذه الظاهرة بارزة في المجتمع العراقي بسبب الحروب واالزمات المتكررة فيه وحاالت الحصار االقتصادي، وكذلك بسبب عدم توزيع موارده بشكل عادل من قبل
... Show Morethe history of Damascus by Ibn ' asaakir d. 571 a.h. 1272 m from local histories books concerned with male citizen narrators, to distinguish between rate and Rob them, this book is more a history of Islamic heritage books on Islamic City, and if we know that Ibn ' asaakir translated it for personal