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.
Discourse is a form of communication, and It carries with it an Intellectual framework, and It is a form of expression to communicate Ideas to people through an interactive process.The interest and analysis of discourse Is one of the most important fields of linguistic studies, and It has a basis In ancient studies, and It has become one of the most Important topics of the study, and (Sayyid al-Sadr) often uses guidance In his sermons.
By extrapolating and analyzing a set of examples received, from the perspective of the deliberative approach and the theory of speech acts, and the statement of the extent to whichh (Sayyid al-Sadr) relied on linguistic elements, and the use of the rank of the speaker In issuing directives, and the
... Show MoreThe construction sector consumes large amounts of energy during the lifetime of a building. This consumption starts with manufacturing and transferring building materials to the sites and demolishing this building after a long time of occupying it. The topic of energy conservation and finding the solution inside the building spaces become an important and urgent necessity. It is known that the roof is exposed to a high amount of thermal loads compared to other elements in a building envelope, so this needs some solutions and treatments to control the flow of the heat through them. These solutions and treatments may be achieved by using nanomaterials. Recently, nanomaterials have high properties, so that this made them go
... Show MoreThe transfer of training process occupies a great importance in achieving the ultimate goal of participating in the training programs , it is sure that this does not take place without the support of the working environment for trainees, and The research aims to personification role the work environment characteristics of supporting the transfer of training.
The research problem is the weakness transfer of training to the work en
... Show MoreThis research deals with the study of the relationship between the success factors as the independent variable and product strategies as the dependent variable , has reacted to these variables to form the frame , which is the research which centered research problem about the extent to which industrial companies the vision and knowledge of Muslim women survive and develop in the business market , which can be expressed about the extent of awareness of corporate success factors and the use of product strategies and what the relationship between the factors and strategies , while expressing the importance of research to make the focus on the product occupies a paramount importance in the industrial sector companies in relation to t
... Show MoreExposing the dorsal superficial skin of rats to partial-depth burn leads to bacterial and microbes Invasion. Topical treatment is required in most superficial burn cases Moist exposed burn ointment (MEBO) protects wounds from infection and enhances healing without any harmful effects of purified chemicals is caused. The topical using of HA gel in rat models with full and partial thickness surgical wounds shows enhancement in wound repair. In this study, we compared the healing efficacy of topical use of hyaluronic acid gel products with MEBO as standard management in rats that were exposed to a partial-thickness burn. The experiment included twenty-four (24) adult albino rats of male sex with weight (150-220 gm) of 3 months’ age divided i
... Show MoreThis study was conducted to determine the role of Phoenix dactylifera pollen grains suspension in improving reproductive efficiency of white male rats. In thisexperiment 40 adult male rats were divided randomly into five equal groups and by following oral administration:the first group was given Phoenix d. pollen grains suspension with concentration 18 mg/kg body weight daily, the second group was given 54 mg/kg, the third group was given 108 mg/kg and fourth group 216 mg/kg body weight, and the last group which represented a control group administrated distilled water only, the administration continued for 40 consecutive days. The effect of Phoenix d. pollen grains in reproductive efficiency was evaluated depending on some parameters such
... Show MoreThe present study was designed in the aquaculture and fish nutrition research aquarium in the College of Veterinary Medicine/Baghdad University from a period 1/3 to 1/6/2013 to investigate the toxicity of the herbicide glyphosate aqua on Barbus sharpeyi fish. Fish fingerlings were used with average weight between 10 – 15 gm to measure the (LC50), and 200 fingerlings were used to know the acute and chronic toxic effect for the herbicide. The fingerlings were randomly distributed as 10 fish for each aquarium. Fish were divided into four treatments and control group (without addition of herbicide). The first processing with a concentration of 0.415 mg/L for a duration of exposure 90 days, the second processing group with a concentration 0.
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The purpose of the present paper is to light on the relationship between jobs design, analysis and its reflections on reinforcing workers' vocational adjustment. The present paper aims to accomplish cognitive and applied goals, top of which, test of functional analysis ability to have effect upon workers' vocational adjustment via job design directly and indirectly owning to the virtual factor practiced by these practices on the sought organization. The problem of the present paper comes with many, the most important is the of how to bolster and back up worker's technical adjustment through good and accurate design for the job.
Based on this problem and goals as to expla
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