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.
Sea level rise (SLR) due to climate change is affecting the coastline, causing shoreline changes, the degradation of mangrove forests, and the destruction of coastal resources. This is the cause of a huge amount of mangrove degradation in many parts of the Ganges–Brahmaputra–Meghna delta. A total of 90% of people have been forced to migrate from the island due to extreme weather conditions. In this study, remote sensing (RS) and geographic information system (GIS) techniques were used for LULC change and shoreline shift analyses of Ghoramara Island. LULC classification was carried out using thirty years of Landsat datasets with intervals of ten years (1990 and 2000) and intervals of five years (2005, 2010, 2015, and 2020). The classific
... Show MoreHere, a high sensitive method for biomarker identification according to nanostructure, using enzyme-linked immunosorbent assays (ELISAs), called Nano-ELISA, was presented. Different shapes of gold nanostructures (star and sphere; GNSs and GNPs) with a particle size of 40 nm for sphere particles were altered with a monoclonal antibody (Ab) as a detector Ab. To amplify the optical signal, gold nanostructures were employed as carriers of the signaling specific antibody against insulin growth factor binding protein- 3 (IGFBP-3). The substrate was catalytically oxidized by the Horseradish Peroxidase (HRP) conjugated gold nanostructure, and HRP also enhanced the optical signals, reflecting the amount of the targeting IGFBP-3. In comparison to t
... Show MoreIn this work, the rate of charge transfer (CT) reaction at the N3-ZnS interface was calculated using a quantitative computational model to evaluate the efficiency of N3-ZnS heterojunction dye-sensitized solar cell devices using different types of solvents. This work discussed the influence of the effective driving energy force on the charge transport rate and performance of N3-ZnS devices with various solvents based on a donor-acceptor model. A solar cell model was used to study the optical efficiency when changing some of its parameters, such as the type of material and the thickness of the film, as they are important factors influencing the quality of the solar cell. It was found that the transition energy varies with different so
... Show MoreChristianity rejected abortion, since its inception, it took a luck against abortion, although there is no mention of it in the Bible, as there is no explicit text for abortion in the Old or New Testament and that the early Christians considered abortion a sin in all stages, and beliefs included abortion as an act of murder. What is forbidden in the Ten Commandments is “Thou shalt not kill”, and it is understood that killing here is either plundering one’s personal life (suicide) or stealing another person’s life (killing), or stealing the life of a person who has not yet been born (aborting fetuses). Based on the above, it was necessary for individuals to search for (Abortion in the Christian Religion / Descriptive Study) The resea
... Show MoreOut of the search for the truth, the reader of the Holy Qur’an should know the fate of the sorcerers whom Pharaoh threatened when they announced it as pure monotheism in front of seeing the stick as it turned into a clear serpent, when they said: We believe in the Lord of the worlds, the Lord of Moses and Aaron, and the clear promise came to cut and crucify the trunks of palm trees, and they said what they said if Being supplicants to God (May God cause us to die as Muslims), did Pharaoh actually carry out what he promised them?? So we studied that subject from this angle. Because what looms on the horizon of the Holy Qur’an is that there is no one who seeks refuge with God Almighty in times of adversity except that God Almighty has
... Show MoreKing Ghazi (1933-1939) was of the Arabic characters that characterized national and
patriotic spirit and that faced the British policy in all its aspects.
King Ghazi distinguished as of Arab nationalist tendencies and called for the
liberalization of Arab lands which were under the rule of the Ottoman Empire. He called for
reunification under the one Arab country, Hence came the King invitations to liberate Kuwait
from the British protectorate and consolidated with Iraq.
King Ghazi established a private radio station in the royal palace (AL zzaahoor) palace
and provided special programs to return of Kuwait to Iraq, this radio station was The
prominent role in the revitalization of the Kuwaiti National Movement, an
The international financial accounting and reporting standards IFRS/IAS represent the set of rules and foundations that the economic entity must follow in the measurement, presentation, and disclosure of the elements of the financial statements, the implementation of adopting the international financial reporting standards contributes to improving the qualitative characteristics of accounting information, so the current research aims to explain the role of adopting the International Accounting Standard (IAS) in improving the qualitative characteristics as well as analyzing the impact of the adoption of IAS.1 in improving the qualitative characteristics of accounting information within the financi
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The increase in military spending has become a feature of the times for many countries, including China. They have sought to increase their defence spending, not with the aim of domination and possession, but rather to protect their economic interests and to secure their foreign trade. The research aims to identify the impact of military spending by studying the nature of defence spending and its role in providing security. And stability and facilitating foreign investment in it, as well as storming the military industry, securing some humanitarian supplies, and participating in a variety of public works that can be used in the civil and military fields, and the aim of the research is to id
... Show MoreDuring the study the current selection seven stations in the Zab River bottom and the Tigris River took samples a month to study the signs of bacterial contamination study coliform and colon fecal Almsobhaat and Almsobhaat Bazah and the total number of bacteria and bacterial gangrene gas causing Knkeran as well as a study to isolate and diagnose some races and types of bacterial pathogens in water or intensityusing the traditional system and the system of intestinal bacteria
The research aims to shed light on the financing structure, which is one of the important pillars of financial management in the commercial banking sector, which enhances its financial position through financing its various investments, which is one of the pillars of the successful economy of the commercial banking sector. in which country. The contents of the research variables, which were represented by the independent variable, financing structure, the dependent variable, and investment decisions in commercial banks, which the researcher tried to address, as the research began with a basic variable that depends on diagnosing the impact of the financin
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