Objective: This study evaluated the effect of immediate dentin sealing on the marginal adaptation of lithium disilicate overlays with three different types of resin-luting agents: preheated composite, dual-cure adhesive resin, and flowable composite. Materials and Methods: Forty-eight maxillary first premolars of similar size were prepared with a butt joint preparation design. The teeth were separated into two primary groups, each with twenty-four teeth: Group DDS: Delay dentin sealing (non-IDS) teeth were not treated. Group IDS: dentin sealing was applied immediately after teeth preparation. Each group was subsequently separated into three separate subgroups. Subgroups (DDS+Phc, IDS+Phc): cemented with preheated composite (Enamel plus HRi, Micerium, Italy), Subgroups (DDS+Dcrs, IDS+Dcrs): cemented with dual-cured resin cement (RelyX Ultimate, 3M ESPE, Germany) and Subgroups (DDS+Fc, IDS+Fc): Cemented with flowable composite (Filtek supreme flowable, 3M ESPE, USA). Using a digital microscope with a magnification of 230x, the marginal gap was measured before and after cementation at four different locations from each surface of the tooth, and the mean of measurements was calculated and analyzed statistically using the independent t-test, one-way ANOVA test, Bonferroni correction at a significance level of 0.05. Results: The samples that were immediately sealed with dentin bonding agent showed lower marginal gaps than delayed dentin sealing, both pre-and post-cementation for all subgroups, with a statistically significant difference (p < 0.01). The marginal gap was significantly lower in the IDS+Fc (48.888 ± 5.5 micro m) followed by the IDS+Dcrs group (53.612 ±5.8 micro m) and IDS+Phc (79.19 9±6.9 micro m) respectively, while the largest marginal gaps were observed in the DDS+Phc group (86.505 ± 5.4 micro m). Conclusion: Generally, the teeth with IDS showed better marginal adaptation than teeth without IDS. The marginal gap was smaller with flowable composite and dual-cure resin cement than with preheated composite.
The demand for expatriate labor to Iraq increased after 2003 as a result of the openness that Iraq experienced, but this expatriate labor, which was requested at an increasing rate, has had economic, social, and political effects on the Iraqi economy in general, and the Iraqi labor market in particular. This is due to the high rates of unemployment, as most of these expatriate workers cause competition to local labor, and thus cause repercussions on the Iraqi economy as a whole, except for those expatriate workers coming with companies working in the oil sector. Iraq's GDP
Zinc oxide (ZnO) nanostructures were synthesized through the hydrothermal method at various conditions growth times (6,7 and 8 hrs.) and a growth temperature (70, 90, and 100 ºC). The prepared ZnO nanostructure samples were described using scanning electron microscopy (SEM) and X-ray diffractometer to distinguish their surface morphologies and crystal structures. The ZnO samples were confirmed to have the same crystal type, with different densities and dimensions (diameter and length). The obtained ZnO nanostructures were used to manufacture gas sensors for NO2 gas detection. Sensing characteristics for the fabricated sensor to NO2 gas were examined at different operating temperatures (180, 200, 220, and 240) ºC with a low gas concentrati
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An experimental and numerical study was carried out to investigate the heat transfer by natural convection in a three dimensional annulus enclosure filled with porous media (silica sand) between two inclined concentric cylinders with (and without) annular fins attached to the inner cylinder under steady state condition. The experiments were carried out for a range of modified Rayleigh number (0.2 ≤Ra*≤ 11) and extended to Ra*=500 for numerical study and for annulus inclination angle of (δ = 0˚, 30˚, 60˚ and 90˚). The numerical study was to give the governing equation under assumptions that used Darcy law and Boussinesq’s approximation and then it was solved numerically using finite difference approximation. It was found that t
... Show MoreTh paper scientifically deals with the Syrian crisis events erupted in 2011 using the historical descriptive and analytical approaches. The importance of the paper comes from the serious crisis that occurred in a region rich of historical crises, and natural resources attracting the attention of the major countries. The paper aims to show the Syrian crisis, its importance to Russia, the United States, and the regional countries, its impact on Russia economically and politically after the intervention, and Russia’s achievements on a global level holding the influential power on international decisions and other global events. The new Russian strategy has proven its worth in preserving its strategic interests as it could help the Syrian
... Show MoreIn this paper, we employ the maximum likelihood estimator in addition to the shrinkage estimation procedure to estimate the system reliability (
The impact of decorating Fe, Ru, Rh, and Ir metals upon the sensing capability of a gallium nitride nanotube (GaNNT) in detecting chlorine trifluoride (CT) was scrutinized using the density functionals B3LYP and B97D. The interaction of the pristine GaNNT with CT was a physical adsorption with the sensing response (SR) of approximately 6.9. After decorating the above-mentioned metals on the GaNNT, adsorption energy of CT changed from −5.8 to −18.6, −18.9, −19.4, and −20.1 kcal/mol by decorating the Fe, Ru, Rh, and Ir metals into the GaNNT surface, respectively. Also, the corresponding SR dramatically increased to 39.6, 52.3, 63.8, and 106.6. This shows that the sensitivity of the metal-decorated GaNNT (metal@GaNNT) increased by in
... Show MoreThe research aims to a statement of specificity of the Controller of (academic achievement, specialty, job title, length of service, Gender) and its impact on performance, Through a proposed appraisal form includes three main axes and each axis including several specialized elements in the supervisory work in form (check list). as is the importance of research to enable officials of oversight bodies financial identify and diagnose performance Controller through what has this observer of the process of scientific properties when performing supervisory work. Be summarized problem of the research that the lack of regulatory institution with the Controller interesting in terms of the necessary characteristics and requirements and inv
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