Background: The marginal fit is the most characteristic that closely related to the longevity or success of a restoration, which is absolutely affected by the fabrication technique. The objective of present in vitro study was to evaluate the effect of four different CAD/CAM systems on the marginal fit of lithiµm disilicate all ceramic crowns. Materials and Methods: Adentoform tooth of a right mandibular first molar was prepared to receive all ceramic crown restoration with deep chamfer finishing line (1mm) and axial reduction convergence angle of 6 degree, dentoform model duplicated to have Nickel-Chromiµm master die. Thirty two stone dies produce from master die and distributed randomly in to four groups (8 dies for each group) according to the type of CAD/CAM system that used: Group A: fabricated with CERAMILL motion2 (Amann Girrbach); Group B:fabricated with CEREC in lab MCXL (Sirona);Group C: fabricated with CORiTEC 250i (imes-icore); Group D: fabricated with ZIRKONZAHN M5 (Zirkonzahn). Marginal discrepancy was measured at four points at each tooth surface. Sixteen points per tooth were measured using digital stereomicroscope at (140X) magnification. Results: ANOVA and LSD post Hoc tests were used to identify and localize the source of difference among the groups. It was found that there is a highly significant difference in the marginal gap mean values between group C and group D, and highly significant differences between group A and group D. Conclusions: From the above result we can conclude that better marginal fit values were may be exhibited by CORiTEC 250i CAD/CAM system.
Background: Dental caries is one of the most significant problems in world health care. Restoring carious primary teeth is one of the major treatment goals for Children, and the light activated resin restoration materials like composite, resin-modified glass ionomer and polyacid-modified which was introduced in dentistry in 1970, widely used in clinical dentistry but its application increased dramatically in recent years because of its biocompatibility, color matching, good adhesive properties of its resemblance in physical and mechanical aspects to tooth. The aim of this study: To evaluate the microleakage of Polyacid-Modified Composite resin Compared to Flowable Hybrid Composite and Resin-Modified Glass ionomer cement. Materials and me
... Show MoreLaser skin wound soldering offers many distinct advantages over conventional closure and laser welding techniques. Objective : to compare the histological effects of human skin wound soldering using 50 % human albumin solder and compound charcoal photosensitiser with 980 nm diode laser acting in various modes of action and parameters. Study Design/Materials and Methods: In this in vitro experimental study , Multiple 3-4 cm long full thickness incisions in a specimen of human skin were soldered using a 4 mm spot diameter beam of 980 nm diode laser(at different laser parameters and modes of action) with 50 % human albumin solder mixed with the compound charcoal at 5 % W/V concentration .After obtaining a successful wound soldering , the wo
... Show MoreThe Study addressed the effectiveness of dialogic communication in online public relations with an audience of higher education institutions in the United Arab Emirates. The study aimed to know about the interest extent of higher education institutions through their websites with the elements of dialogic communication in online public relations to communicate with their audience. The researcher used survey methodology and content Analysis tool as an essential tool for collecting information. Some of the important results of the study are: The websites of higher education institutions in terms of indicators of ease of use; the main links on the websites are clearly available on the opening page, there is a map on the websites, reduce depe
... Show Moreإحدى أهم الطرق لتقصي توزيع المجرات عبر الزمن الكوني هي دالة اللمعان LF بدلالة كتلة القرص الباريوني ψS(Mb)، القدر . لقد درسنا تقديرًا لكثافة كتلة الباريون في عينة من المجرات الحلزونية القضيبية وغير القضيبية من الادبيات السابقة، والتي تتضمن فعليًا، لكل صنف من الاجرام السماوية ذات المحتوى الباريون المرئي، جزءًا لا يتجزأ من ناتج دالة الضيائية (LF) ونسبة الكتلة إلى الضوء. استخدمت تقنية الانحدار المتعدد لحزمة الب
... Show MoreIn recent years, the world witnessed a rapid growth in attacks on the internet which resulted in deficiencies in networks performances. The growth was in both quantity and versatility of the attacks. To cope with this, new detection techniques are required especially the ones that use Artificial Intelligence techniques such as machine learning based intrusion detection and prevention systems. Many machine learning models are used to deal with intrusion detection and each has its own pros and cons and this is where this paper falls in, performance analysis of different Machine Learning Models for Intrusion Detection Systems based on supervised machine learning algorithms. Using Python Scikit-Learn library KNN, Support Ve
... Show MoreThis study is concerned with the comparison of the results of some tests of passing and dribbling of the basketball of tow different years between teams of chosen young players in Baghdad. Calculative methods were used namely (Arithmetic mean, Value digression and T.test for incompatible specimens). After careful calculative treatments, it has been that there were abstract or no abstract differences in the find results of chestpass, highdribble and cross-over dribble. The clubs were: (Al-Khark, Air defence, Police and Al-Adamiyah) each one separate from the other for the year (2000-2001). After all that many findings were reached such as the lack of objective valuation (periodical tests) between one sport season and the other. In the light
... Show MoreSome research reports that cognitive grammar (CG) theory has good contributions to teaching English as a foreign language. In this research, the researchers seek to apply this theory and its principles when teaching the simple present tense to Iraqi students who face difficulties in differentiating between the multiple usages of this tense. To achieve this objective, the researchers have conducted an experimental study on a group of 60 Iraqi students in the University of Baghdad, College of Education for Women. Langacker’s (2003) theory has been adopted in the analysis of the cognitive relations to understand the common and different connections of these usages of the simple present. The study has concluded that the cognitive grammar t
... Show MoreIn regression testing, Test case prioritization (TCP) is a technique to arrange all the available test cases. TCP techniques can improve fault detection performance which is measured by the average percentage of fault detection (APFD). History-based TCP is one of the TCP techniques that consider the history of past data to prioritize test cases. The issue of equal priority allocation to test cases is a common problem for most TCP techniques. However, this problem has not been explored in history-based TCP techniques. To solve this problem in regression testing, most of the researchers resort to random sorting of test cases. This study aims to investigate equal priority in history-based TCP techniques. The first objective is to implement
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