Zirconia ceramic restoration (ZCR) has a higher fracture incidence rate than metal ceramic restoration. Different surface treatments were used to improve fracture performance of ZCR such as grit blasting (GB) by aluminium oxide powder. This type of surface treatment generate residual stresses on veneering ceramic causing crack initiation and ending with a fracture. In order to overcome the stress generated by GB, zirconia surface coating is used as a surface treatment to improve fracture resistance and to accommodate stresses along the ZCR layers. Fifty zirconia ceramic crowns were fabricated and divided according to the type of surface treatment into three groups; the first group is (ZG), involving 20 cores were coated with a mixture of partially-sintered zirconia powder (PZP) and glaze ceramic powder; the second group is (ZL), including of 20 cores were coated with PZP and liner ceramic paste. The third group is grit blasting (GB), preparing of 10 fully sintered cores at 1350 °C which then abraded by 50 µm aluminium oxide powder. The groups ZG and ZL were further subdivided into ZG26, ZG47, ZL26 and ZL47 based on two PZP sizes (47 and 26 µm). Each treated core was veneered with the veneering ceramic layer. Fracture resistance (FR) was measured by the universal testing machine. Finite element analysis (FEA) was used to simulate the stress distributions on the coated and non-coated zirconia crown models. The ZG47 group had higher FR (647.92 ± 97.33 N) and a significant difference (P < 0.00) compared to GB and other coated groups. The FEA exhibited lower and evenly distributed stresses of the zirconia glaze model than the zirconia liner and the non-coated models. The ZG47 coating considered as an alternative method to GB treatment which increases the FR which significantly improved the clinical performance of the ZCR.
Abstract:
The research aims to identify how to audit potential liabilities and contingent liabilities in light of the pandemic and its reflection on the auditor's report. The research problem is represented by the complexity of the process of checking potential liabilities and contingent liabilities in insurance companies, which was negatively reflected in the auditor's neutral technical opinion. The researchers hypothesize that auditing potential liabilities and contingent liabilities in light of the Corona pandemic is positively reflected in the auditor's report. The research concludes that the process of checking potential liabilities and contingent liabilities is
... Show MoreThe importance of the research comes from dealing with the problem of lack of traffic awareness, which causes accidents and the occurrence of human and material losses, and the research aims to study the role of satellite channels in forming traffic awareness among the public, and a sample was chosen from Baghdad consisting of (280) individuals, male and female, and used the questionnaire tool. To obtain the data, which included several questions, the results were analyzed statistically and several results were reached, the most important of which is that there is an interest among the public in following traffic programs at a rate of one to two hours to receive information through traffic programs and to identify and apply gener
... Show MoreEquilrium, kinetic and mechanistic studies for thcoordination of
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some amino acids "'AA'1
glycine, alanine, .a:ncl histidine, to Cr (Ill)
center of trans .[Cr(ox}2(B.2 0hr {TJ'} cornplein monderarely acidic
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c.onsta:nts at 25°C .were found logKequ.=4.95J ,5.206and5.128for glycine, alap.ine, md
... Show MoreA New Mannich base [N-(4-morpholinomethyl)-1,8-naphthalimide] (L), was synthesized and characterized by C.H.N analysis, FTIR, UV-Vis and 1HNMR spectral analysis. Metal ion complexes of (L) with Pt(IV), Rh(III), Ru(III) and Pd(II) ions were prepared and characterized by FT-IR, and UV-Vis spectroscopy, elemental analysis (C.H.N), flame atomic absorption techniques as well as magnetic susceptibility and conductivity measurements. The results showed that metal ion complexes for all complexes were found in [1:2] [M:L] ratio except for Pd(II) complex which was found in [1:1] [M:L] ratio. Hyperchem-8 program has been used to predict structural geometries of the (L) and it's complexes in gas phase. The electrostatic potential (EP) of the (L) was
... Show MoreThis study deals with a prominent critical term - poetics - in critical studies as an area related to uncovering the laws of creative and aesthetic discourses (Preaching)، and the various functions that accompany it in literary texts. So، the study employs the pioneers' works of this theory specially the eastern theorists in making a parallel comparing study of the text book of " the Magic and Poetry” by Al-Lisan Al-Din bin Al-Khatib (776 AH). It displays the utility of the concept of poetics in the referred book pointing to the illumination of various functions that، in turn، reflected the
Laportea aestuans L. (Chew), Commelina virginica (L.) and Sida rhombifolia (L.) are common wild plants used in treating several ailments including diarrhea, dysentery, hernia, oedema, ulcers and many more in traditional African medicine especially, Nigeria. The potentials of Random Amplified polymorphic DNA (RAPD) primers in delimiting intra-specific variation in L. aestuans, C. virginica and S. rhombifolia was assessed using three RAPD primers. Plant and soil samples were collected from 19 local government areas in Lagos State and assessed for genetic and biochemical relationships. A total of 56 bands were produced of which 44 were polymorphic. Maximum number of bands (21) was produced by OPY
... Show MoreNew derivatives of thiosemicarbazide were synthesized by reaction of different aromatic aldehydes and ketones with thiosemicarbazide to give schiff-bases 1(a-d) . schiff-bases have been used for synthesized the thioimidazolidine 2(a-d) by reaction of schiff-bases with ethyl chloroacetatein in presence of anhydrous sodium acetate that transformed part of it in to Beta-lactam 3(a-b) compounds with phenyl acetic acid and thionyl chloride , The compounds 4(a-b) came from the reactor of 4-bromobenzaldehyde with compounds 2(a-b) , as well as reaction of compounds 2(b-d) with methyl iodide and anhydrous potassium carbonate to give 5 (b-d) , then added hydrazine hydrate formed 6(b-d) , then
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