ABSTRACT Background: Color changes that are detectable to human eye can affect the esthetic appearance of ceramic veneers. The purpose of this study was to evaluate and compare the effect of artificial accelerated aging on the color of ceramic veneers cemented with different resin cements. Materials and Methods: Sixty discs were prepared with 0.5 mm thickness, 30 discs made from IPS e.max press (Ivoclar Vivadent) and 30 discs were made from VITA Enamic (VITA Zahnfabrik). The discs were cemented with three resin cements: Variolink Veneer MV 0 shade (Ivoclar Vivadent), Rely X veneer Translucent shade (3M ESPE) and NX3 Nexus Clear shade (Kerr Corporation) with 0.1 mm thickness. The spectrophotometer Easyshade Advance was used to measure the color parameters (Lightness, axis a* of chroma and axis b*of chroma) immediately after cementation, after 150 and 300 hours of aging. The specimens were subjected to artificial accelerated aging in Accelerated Weathering Tester. Color change greater than 3.3 was considered unacceptable. One-way ANOVA, paired t-tests and Bonferroni adjusted t-test were used for statistical analysis (p <0.05). Results: Artificial aging caused high significant color change in both ceramic types, but there were non-significant difference in color change among the three resin cements used. The color change was between1.997-14.8 after 150 hours and it was between 2.179-15.68 after 300 hours. The color change of e.max discs after aging were within acceptable limit<3.3 whereas Vita Enamic specimens had shown unacceptable color change >3.3 after aging. Conclusions: The majority of color change after aging related to veneering materials while resin cement have only slight effect on color change after aging. IPS e.max had shown an acceptable color change after aging, so it is suitable for fabrication of restorations in esthetic zone while Vita Enamic should not be used in esthetic zone since it has poor color stability according to the results of this study.
Background: This study is to evaluate the necessity of prescribing prophylactic antibiotics for nasal packing in spontaneous epistaxis. There are few published papers of infective complications in such patients.
Methods: This prospective study analysed 149 consecutive patients admitted to AL-Kindy teaching hospital with spontaneous, epistaxis, who underwent nasal packing over 2 years period . in the first year, 78 patients received prophylactic antibiotics , In the second year 71 patients were not given prophylatic antibiotics. Exclusion criteria included antibiotics prescribed for unrelated pathology and post-operative epistaxis. Signs and symptoms of acute otitis m
... Show MoreThe impact of Jurisprudence Rules in Addressing Contemporary security Challenges
Islamic jurisprudence is related to various fields of knowledge, as it is a science of great value, great in impact, and among the most prominent features of jurisprudence comes the jurisprudence rules. It regulates the principles of the doctrine for the jurist. Therefore, the main this research focuses on (the impact of jurisprudence rules in addressing contemporary security challenges). It is the relationship between jurisprudence rules and achieving security. Its fruit would be a statement of the distinguished impact of jurisprudence rules on the stability of the country, and its leading role in maintaining, strengthening, and pre
... Show MoreThe cities are not yet a temporal status in the process of the human and civilization development. The cities consider as a life pattern, this mean that people cannot live without cities, which surround us. Several phenomena like globalization, revolution of information, technical development, increased of consumption, do not confirmed without the living in cities. The urbanization – in its simple meaning – means transferring from rural community to city community. In other word, it means that socioeconomic changes happened subject to the patterns and conditions of the urban life. Each government depend a certain policy, this policy contains set of plans and programs, that targeting to affect the population factors and the st
... Show MoreAlkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms . They are a large family of compounds synthesized by plants in addition to the bacteria, fungi, and animals, they often have pharmacological effects. The aim of this study is to isolate and identified alkaloids in a newly studied, wild Iraqi plant named
... Show MoreBecause of the fierce competition between service organizations on the one hand and the increasing demands of customers on the other. Therefore, these organizations sought to distinguish their service by taking care of all aspects. One of these important aspects is the service encounter environment and its reflection on customer emotions, so we choose the current research to clarify the importance and impact on customer satisfaction, the problem of research is how the interest of Iraqi restaurants in the service encounter environment and how to care about its elements and whether this interest is sufficient to reflect the satisfaction of the customer. the goal of the current research was to clarify how much the application of the
... Show MoreDestiny functional theory (DFT) calculations are undertaken in order to scrutinize the electrochemical and calcium (Ca) storage characteristics of a graphyne-like aluminum nitride monolayer (G-AlNyen) as an electrode material for Ca-ion batteries (CIBs). The results show that the change in internal energy as well as the cell voltage values for the CIB with the G-AlNyen anode are comparable to others with two-dimensional 2D nano-materials. It is shown that Ca is adsorbed primarily onto the center of a hexagonal and triangular ring of G-AlNyen with absorption energies of −2.06 and −0.42 eV. After increasing the concentration of Ca atoms on G-AlNyen, the adsorption energy as well as the cell voltage decreases. Lower values of 0.15–0.32 e
... Show MoreThis research examines the impact of construction technology systems in contemporary architectural production through the study of the evolution in it systems, construction materials and methods of construction in addition to the digital revolution which provided possibilities of structural and architectural design in creating a distinct architectural product, as considered construction systems technology is the source of creativity in the architectural product, the research is assumed that the construction systems technology have achieved a structural innovation in production through the materials and methods of construction and digital design.
For Long time technology was connected to the
Over the last two decades, several sustainability assessment methods have developed as key accelerators for the development and improvement of sustainable industrial buildings. Some of these systems, like as LEED or BREEAM, are considered international, whereas others, such as Pearl Rating Systems (PRS), are local. Although they all share similar goals, they can lead to the construction of green buildings or the improvement of the efficiency of existing conventional buildings. Each technique has its structure, certification process, and weighting norms. The inequalities have prompted various questions about whether global assessment systems appropriately consider the country’s national settings. This study aims to compare the Pear
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