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A Comparison of Vertical Marginal Fit of different Brands of Translucent Zirconia Crown Restorations

Background: As the development of zirconia crown using CAD/CAM technology, the usage of full zirconia crown is gradually increased. The aim of this in-vitro study was to evaluate and contrast the vertical marginal fit of single all-ceramic translucent zirconia crowns constructed from different brands translucent zirconia blanks. Materials and Methods: An acrylic resin model of a left maxillary premolar was prepared all around the tooth with (1 mm) depth and 3D scanning to get fifteen STL files, then distributed into three groups (Imes-icor, Whitepeaks and Dental direct), 3D scanning and milling machine by Imes-icor CAD/CAM devise. Marginal gaps along vertical planes were measured at four indentations at the (mid mesial, mid distal, mid buccal, mid palatal) using a light microscope at a magnification of x100. One-way ANOVA, LSD tests were performed to determine the mean and standard deviation of the three blanks groups. Results: Statistically high significant difference (p < 0.00) was found between the groups. The marginal gap value of the groups varied Whitepeaks crowns was (105.42 ± 7) μm, which was significantly higher than the two overall mean marginal gap measured for the Imes-icor crowns (59.3 ± 4) μm and Dental direct crowns (54.5 ± 4.9) μm, the Dental direct which was lowers overall mean vertical gap measurement. Conclusions: The marginal gap values of Dental direct crowns is considerably lower than that of Whitepeaks crown, The marginal gap values of all the groups made of monolithic high translucent Y-TZP demonstrated acceptable marginal gaps values.

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Publication Date
Sun Jun 30 2002
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
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Publication Date
Fri Apr 01 2022
Journal Name
Baghdad Science Journal
Fractographic Analysis of Tensile Failures of Zirconia Epoxy Nanocomposites

This work characterizes the fractographic features of the neat epoxy and ZrO2 epoxy nanocomposites. All samples were subjected to a tensile test to determine the tensile strength and tensile modulus. SEM images were used to study the morphology of the fractured surface. The fractographic of the fracture surfaces were studied by microstructure analysis program (j-images) to specify the effect of ZrO2 nanoparticles on tensile performance and failure mechanism for ZrO2 epoxy nanocomposites. The tensile test results show that the addition of ZrO2 nanoparticles (2, 4, 6, 8, and 10 vol.%) to the epoxy matrix leads to increase the tensile strength about 40% for optimal content of ZrO2 nanop

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Publication Date
Fri Jan 13 2023
Journal Name
Journal Of The Faculty Of Medicine Baghdad
A short-term comparison between the effect of two different concentrations of methotrexate on ovarian tissues and function of female albino rats: A short-term comparison between the effect of two different concentrations of methotrexate on ovarian tissues and function of female albino rats

Back ground: methotrexate is an antifolate that is widely used in cancers and inflammatory or auto- immune diseases, it is also known to be contraindicated in pregnancy, breast feeding and not recommended in patients planning to be parents since it has a harmful effect on fetus and gonads.

    Ovarian function can be evaluated by certain parameters like the levels of female hormones or anti- Mullerian hormone which is considered as a good indicator for this purpose or histopathological examination of ovarian follicles especially the primordial follicles.

  Objective: the aim of this study is to determine the effect of two different concentrations of me

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Publication Date
Wed Jul 01 2020
Journal Name
Iop Conference Series: Materials Science And Engineering
Experimental and Numerical Comparison of Prestressed Perforated Concrete Rafters of Different Configurations
Abstract<p>This paper demonstrates an experimental and numerical study aimed to compare the influence of openings of different configurations on the flexural behavior of prestressed concrete rafters. The experimental program consisted of testing six simply supported prestressed concrete rafters; 5 rafters are perforated, and the other one is solid as a reference. All rafters were tested under monotonic midpoint load. The variable which has been investigated in this work was the opening’s configuration (quadrilateral or circular) with the same upper and lower chords depths. The results indicate improvement in the beam flexural behavior using the circular openings compared to the quadrilateral o</p> ... Show More
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Publication Date
Sat Apr 30 2022
Journal Name
Iraqi Journal Of Science
Comparison Different Estimation Methods for the Parameters of Non-Linear Regression

   Nonlinear regression models are important tools for solving optimization problems. As traditional techniques would fail to reach satisfactory solutions for the parameter estimation problem.  Hence, in this paper, the BAT algorithm  to estimate the parameters of  Nonlinear Regression models is used . The simulation study is considered to investigate the performance of the proposed algorithm with the maximum likelihood (MLE) and Least square (LS) methods. The results show that the Bat algorithm provides accurate estimation and it is satisfactory for the parameter estimation of the nonlinear regression models than MLE and LS methods depend on Mean Square error.

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Publication Date
Wed Dec 25 2019
Journal Name
Journal Of Engineering
Comparison of Different DEM Generation Methods based on Open Source Datasets

Digital Elevation Model (DEM) is one of the developed techniques for relief representation.  The definition of a DEM construction is the modeling technique of earth surface from existing data. DEM plays a role as one of the fundamental information requirement that has been generally utilized in GIS data structures. The main aim of this research is to present a methodology for assessing DEMs generation methods. The DEMs data will be extracted from open source data e.g. Google Earth. The tested data will be compared with data produced from formal institutions such as General Directorate of Surveying. The study area has been chosen in south of Iraq (Al-Gharraf / Dhi Qar governorate. The methods of DEMs creation are kri

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Publication Date
Tue Apr 01 2008
Journal Name
Journal Of The Faculty Of Medicine Baghdad
Comparison Between The Efficacy of Different Medical Herbs on Cryptosporidium spp.

Objectives:
The study was planned to show the effect of different medicinal plants extracts on Cryptosporidium spp.
Materials and Methods:
The experimental study was performed in laboratory mice to show the efficacy of different medical plants extracts (Achillea fragrantissima, Artemisea herba-alba,
Cardaria draba, Mentha longifolia , Olea europea, Prosopis farcta, Punica granatum, Teucrium polium and Ziziphus spina-charisti on shedding of Cryptosporidium spp. oocysts.
Results:
In a study on the effect of medical plant extracts on the shedding of oocysts in mice, it was found that different medical plants extracts decrease the shedding of
Cryptosporidium oocysts in mice. Using 250 mg / kg B.W

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Publication Date
Wed Dec 25 2019
Journal Name
Journal Of Engineering
Comparison of Different DEM Generation Methods based on Open Source Datasets

Digital Elevation Model (DEM) is one of the developed techniques for relief representation.  The definition of a DEM construction is the modeling technique of earth surface from existing data. DEM plays a role as one of the fundamental information requirement that has been generally utilized in GIS data structures. The main aim of this research is to present a methodology for assessing DEMs generation methods. The DEMs data will be extracted from open source data e.g. Google Earth. The tested data will be compared with data produced from formal institutions such as General Directorate of Surveying. The study area has been chosen in south of Iraq (Al-Gharraf / Dhi Qar governorate. The methods of DEMs creation are kriging, IDW (inver

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Publication Date
Thu May 28 2020
Journal Name
Iraqi Journal Of Science
Comparison between Horizontal and Vertical OFETs by Using Poly (3-Hexylthiophene) (P3HT) as an Active Semiconductor Layer

In this paper, a comparison between horizontal and vertical OFET of Poly (3-Hexylthiophene) (P3HT) as an active semiconductor layer (p-type) was studied by using two different gate insulators (ZrO2 and PVA). The electrical performance output (Id-Vd) and transfer (Id-Vg) characteristics were investigated using the gradual-channel approximation model. The device shows a typical output curve of a field-effect transistor (FET). The analysis of electrical characterization was performed in order to investigate the source-drain voltage (Vd) dependent current and the effects of gate dielectric on the electrical performance of the OFET. This work also considered the effects of the

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Publication Date
Tue Nov 19 2024
Journal Name
Journal Of Baghdad College Of Dentistry
An evaluation of the influence of different finishing lines on the fracture strength of full contour zirconia CAD/CAM and heat press all-ceramic crowns

ABSTRACT Background: One of the major problems of all ceramic restorations is their probable fracture against the occlusal forces. The objective of this in vitro study was to evaluate the effect of two gingival finishing lines (90°shoulder and deep chamfer) on the fracture resistance of full contour CAD/CAM and heat press all-ceramic crowns. Materials and Methods: Thirty two maxillary first premolars were prepared to receive full contour CAD/CAM (zolid) and heat press (Cergo Kiss) ceramic crowns using a special paralleling device (Parallel-A-Prep). The teeth were divided into four groups according to the type of finishing line prepared. Each crown was cemented to its corresponding tooth using self-etch, self-adhesive dual cure resin ceme

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