The zirconia ceramic restoration (ZCR) is used as substitutes for the metal-ceramic restoration. Clinical studies demonstrating of ZCRs showed a high fracture incidence of veneering layer than metal-ceramic restorations. This attributed to the low bond strength of zirconia to veneering ceramic as a result of lacking of glass content in its matrix. Surface treatment was proposed to improve the bonding strength between zirconia and veneering ceramic. Several studies revealed that some treatment such as airborne particle abrasion (APA) is responsible for generating chipping of veneering ceramic. The study aimed to develop a new zirconia coatings to increase bonding strength between zirconia substrate and veneering porcelain. Three groups of 150 zirconia specimens (discs, rods and crowns) were divided according to the type of surface treatments; Group M1 designated unsintered zirconia specimens coated with a mixture of glaze porcelain powder and partially-sintered zirconia powder prepared at 1100 °C with two particle sizes; A (26 ± 0.3 μm) and size B (47 ± 0.5 μm), group M2 was coated with mixture of ceramic liner paste and same selected particle sizes of partially-sintered zirconia powders. The coated groups (M1 and M2) subdivided according to powder sizes into M1A, M1B, M2A and M2B. APA group (as control) of sintered zirconia specimens abraded with 50 μm aluminium oxide powder. Surface area roughness (Sa) was measured by surface texture analyser. Surface morphology and elemental composition were analysed by scanning electron microscope (SEM). Crystallographic phases were identified by X-ray diffraction (XRD). The coefficient of thermal expansion (CTE) was assessed by a thermomechanical analyser. For shear bond strength (SBS) test was evaluated by a universal testing machine (UTM). The fracture strength (FS) test prepared and measured by Cercon CAD/CAM system and UTM. Fractographic analysis for SBS and FS were examined by a stereomicroscope and SEM. For each test and measurement, 10 specimens were used per group. Finite element analysis (FEA) was used to simulate and predict the iv stress distributions of the static oblique load in coated and non-coated zirconia crown models. The collected data were analysed by one-way ANOVA and Tukey HSD test at (P<0.05). Surface roughness results showed significant differences among all groups (P<0.000). The M1B group exhibited a higher Sa value (10.33 ± 0.59 μm) among the tested groups. XRD analysis showed tetragonal and monoclinic phases in the control group while only tetragonal was detected in the coated groups. The SBS values for coated groups were higher than the control group. The M1B group showed higher and significant differences in SBS value (37.54 ± 4.38 MPa) among other tested groups (P<0.05). The FS test indicated that coated M1B group (647.92 ± 97.33 N) higher than the other groups (P<0.00). FEA showed the coated crown models have lower stress level than the non-coated model. The new coating (M1B) by airbrush spray technique considered as an alternative way to APA treatment to improve the bond strength of zirconia substrate to veneering ceramic and indicating as an applicable surface treatment for improving the clinical performance of the coated ZCR.
This study is descriptive and theory of Dawn syndrome as the problem of research lies in the need to identify the identification of the causes of Dawn syndrome and its symptoms and methods of dealing with it, which has become a problem that needs treatment, especially after the numbers have become high in Iraq, which has not yet taken the necessary importance for treatment and care.
The objectives of the research were summarized in the identification of the most important causes of Dawn syndrome and its symptoms and diagnosis and ways or methods of dealing with people with Dawn syndrome in order to develop therapeutic plans for him.
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The danger of the attacks of 9/11 in America, mainly on the WorldTrade Center at Ground Zero, had brought America into a position thatnever seen before. People who lived there faced a historical calamity marked a turning point in history and a beginning of a new era. Thepaper examines the behavior of traumatized individuals in relation tosociety that trauma involves both. The socio cultural approach willachieve the goal. It studied the responses of the individuals to the event and the motives behind these reactions. Don DeLillo, a member of apost 9/11 group of writers, an American novelist of Italian origin, through his portrayal of the characters, tries to present a vivid image t
... Show MoreIn this work we experimentally investigated SWCNTs and MWCNTs to increase their thermal conductivity and electrically functionalization process using different reagents ((nitric acid, HNO3 followed by acid treatment with H2SO4), then washed with deionized water (DW) and then treated with H2O2 via ultrasonic technique. Then repeated the steps with MWCNTs and compare their results in an effort to improve experimental conditions that efficiently differentiate the surface of the single walled carbon nanotubes (SWCNTs) and multi walled carbon nanotubesi(MWCNTs) that less nanotubes destroy and to enhance the properties of them and also to reduce aggregation in liquid. the results were prove by XRD, and infrared spectroscopy (FTIR). The FTIR sp
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KE Sharquie, AA Noaimi, EA Al-Janabi…, Journal of Cosmetics, Dermatological Sciences and Applications, 2013 - Cited by 13
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The phenomenon of child labor, any activity performed by a child and represents a contribution to the production, this phenomenon had been rife in Iraqi society, after that the proportion of child labor for the age group (6-14 years) amounting to 3% in 2006, became for the same age group of 8% in 2008*.
It is recognized that each phenomenon reasons, the phenomenon which our atten
... Show MoreThis study aims to evaluate the performance of the sewage treatment plant in Al- Diwaniya, one of cities in the southern part in Iraq. This evaluation could be used to facilitate effluent quality assessment or optimal process control of the plant. The influent reaching the plant is considered a medium to strong in strength with BOD5/COD ratio in the range 0.23 and 0.69 which can be considered an easily degradable sewage by the biological processes performed by the activated sludge unit. The quality of the effluent was found to be higher than the Iraqi standards for disposal to water bodies. The BOD5/COD ratios of the treated sewage varied over a wide range as low of 0.13 to 1.48 indicating operational problems in the plant. Regressio
... Show MoreEnamel White Spot Lesions (EWSLs) are a common dental condition characterized by being opaque or chalky white in appearance. In this review, an overview of the etiology, prevention, and treatment techniques for EWSLs is presented. Enamel demineralization caused by bacteria in dental plaque which releases acids upon the consumption of fermentable carbohydrates causing mineral loss is thought to be the main cause of those lesions, which could be predisposed through orthodontic treatment, poor diet, inadequate oral hygiene and certain medical conditions. So, sustaining an adequate carbohydrate consumption, proper fluoride exposure and good oral hygiene are some of the practices which aid in these lesions’ prevention. Although the suc
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This paper was aimed to study the efficiency of forward osmosis (FO) process as a new application for the treatment of wastewater from textile effluent and the factors affecting the performance of forward osmosis process.
The draw solutions used were magnesium chloride (MgCl2), and aluminum sulphate (Al2 ( SO4)3 .18 H2O), and the feed solutions used were reactive red, and disperse blue dyes.
Experimental work were includes operating the forward osmosis process using thin film composite (TFC) membrane as flat sheet for different draw solutions and feed solutions. The operating parameters studied were : draw solutions concentration (10 – 90 g/l), feed solutions concentration (5 – 30 mg/l), draw solutions flow rate (10 – 50 l/hr
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