Background: Ceramic veneers represent the treatment of choice in minimally invasive esthetic dentistry; one of the critical factors in their long term success is marginal adaptation. The aim of the present study is to evaluate the marginal gap of ceramic veneers by using two different fabrication techniques and two different designs of preparation. Material and methods: A typodont maxillary central incisor used in the preparation from which metal dies were fabricated, which were in turn used to make forty stone dies. The dies divided into four experimental groups, each group had ten samples: A1: prepared with butt-joint incisal reduction and restored with IPS e.max CAD, A2: prepared with overlapped incisal reduction and restored with IPS e.max CAD. B1: prepared with butt-joint incisal reduction restored with IPS e.max press. B2: prepared with overlapped incisal reduction and restored with IPS e.max press. The marginal gap was measured with direct view technique using digital microscope at a magnification of 230x. Measurements were recorded for four surfaces for each sample and the maximum value was taken to represent that sample. Results: The data were analyzed with two-way ANOVA and independent samples t-tests. These tests revealed highly significant effects of both the preparation design and the technique of fabrication on the marginal gap (p=0.00), with CAD/CAM veneers, group A1 recorded the least marginal gap and pressing group, B2 showed the highest gap values. There was no significant effect of the interaction between the two parameters on the marginal gap. Conclusion: the CAD/CAM veneers with butt joint incisal reduction produced the most accurate margins while the least favorable combination was the pressable ceramic veneers with overlapped incisal reduction.
Abstract
In this paper presents two dimensional turbulent flow of different nanofluids and ribs configuration in a circular tube have been numerically investigation using FLUENT 6.3.26. Two samples of CuO and, ZnO nanoparticles with 2% v/v concentration and 40 nm as nanoparticle diameter combined with trapezoidalribs with aspect ratio of p/d=5.72 in a constant tube surface heat flux were conducted for simulation. The results showed that heat flow as Nusselt number for all cases raises with Reynolds number and volume fraction of nanofluid, likewise the results also reveal that ZnO with volume fractions of 2% in trapezoidal ribs offered highest Nusselt number at Reynolds number of Re= 30000.
Key
... Show MoreBoth methotrexate and vitamin D3 are used in combination for the treatment of various diseases. The aim of this study is to highlight the effect of vitamin D3 on methotrexate-induced jejunum damage using biochemical and histopathological studies. Seven groups of both sexes of rats were selected and treated as follows: (Group I and Group II) : control 1,control 2 (I.P normal saline) daily for 14 and 21 days respectively ; (Group III and Group IV) :vitamin D3 groups (500 IU/rat/day) orally for 14 and 21 days, respectively;(Group V): once daily dose of methotrexate 20mg/kg, I.P injected for 4 days;(Group VI):vitamin D3 (500 IU/rat/day) once daily for 14 days and methotrexate (20 mg/kg I.P) injected only at day 10;.(Group
... Show MoreExperiments were conducted to study axial liquid dispersion coefficient in slurry bubble column of 0.15 m inside diameter and 1.6 m height using perforated plate gas distributor of 54 holes of a size equal to 1 mm diameter and with a 0.24 free area of holes to the cross sectional area of the column. The three phase system consists of air, water and PVC used as the solid phase. The effect of solid loading (0, 30 and 60 kg/m3) and solid diameter (0.7, 1.5 and 3 mm) on the axial liquid dispersion coefficient at different axial location (25, 50 and 75 cm) and superficial gas velocity covered homogeneous-heterogeneous flow regime (1-10 cm/s) were studied in the present work. The results show that the axial liquid dispersion coeffic
... Show MoreMycotoxins are secondary by-products of mold metabolism and are accountable for human and animal mycotoxicosis. The most serious trichothecenic mycotoxin is the fungal T-2 mycotoxin. T-2 mycotoxin impaired nutrient absorption, metabolism, and then, eliciting severe oxidoreductive stress. Diet plays a key role beyond the supply of nutrients in order to promote animal and human health. Organic acids have been commonly used to exert antioxidative stress capacity in the liver and gut ecosystem. This study is planned to explore, the competence of using (X-MoldCid®) during chronic T-2 mycotoxicosis course in rat. Rats were allocated into 4 main groups, (CN-Gr), negative control and was allowed for the free access to the normal rats chow and the
... Show MoreTenofovir disoproxil fumarate, a nucleotide reverse transcriptase inhibitor utilized for the treatment of hepatitis B virus and human immunodeficiency virus infections; and is now one of the most widely used antiretroviral drug. However, tenofovir disoproxil fumarate can induce nephrotoxicity, which may be attributed to the interaction between such drug and the organic anion transporters (hOAT1, and OAT3) with consequent changes in levels of some parameters that may have a role in nephrotoxicity. Thiazide diuretics have high to intermediate potency of inhibition of OAT1s and OAT3; thus, it may possess nephroprotective effects. This study was designed to investigate whether hydrochlorthiazide has nephroprotective effects on tenofovir diso
... Show MoreIn the present work experiments were conducted to study the effect of solid loading (1,5 and 9 vol.%) on the enhancement of carbon dioxide absorption in bubble column at various volumetric gas flow rate (0.75, 1 and 1.5 m3/h) and absorbent concentration (caustic soda)( 0.1,0.5 and 1 M ). Activated carbon and alumina oxide (Al2O3) are used as solid particles. The Danckwerts method was used to calculate interfacial area and individual mass transfer coefficients during absorption of carbon dioxide in a bubble column. The results show that the absorption rate was increased with increasing volumetric gas flow rate, caustic soda concentration and solid loading. Mass transfer coefficient and interfac
... Show MoreThis study aimed to investigate the impact of implementing Glycetin by injection on the productive features of local Iraqi chickens. 100 female hens and 20 roosters from a local Iraqi chicken population, at age 26 weeks. The sample was divided into three groups, in addition to a control group. Each experimental group had 25 female hens, with the same procedure being performed for each individual hen, and 20 roosters, which were reared separately for the purpose of artificial insemination. The avian specimens were housed in separate enclosures, and the experimental conditions were allocated as follows: the initial condition (Control Group) did not receive any injections, whereas condit
In this paper We introduce some new types of almost bi-periodic points in topological bitransfprmation groups and thier effects on some types of minimaliy in topological dynamics
Reflective cracking is one of the primary forms of deterioration in pavements. It is widespread when Asphalt concrete (AC) overlays are built over a rigid pavement with discontinuities on its surface. Thus, this research work aims to reduce reflection cracks in asphalt concrete overlay on the rigid pavement. Asphalt Concrete (AC) slab specimens were prepared in three thicknesses (4, 5, and 6 cm). All these specimens were by testing machine designed and manufactured at the Engineering Consulting Office of the University of Baghdad to examine for the number of cycles and loads needed to propagate the reflection cracking in the asphalt concert mixture at three temperatures (20, 30, and 30°C). It was noticed that the higher thickness A
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