Background: Restoration of the gingival margin of Class II cavities with composite resin continues to be problematic, especially where no enamel exists for bonding to the gingival margin. The aim of study is to evaluate the marginal leakage at enamel and cementum margin of class II MOD cavities using amalgam restoration and modern composite restorations Filtek™ P90, Filtek™ Z250 XT (Nano Hybrid Universal Restorative) and SDR bulk fill with different restoratives techniques. Materials and method: Eighty sound maxillary first premolar teeth were collected and divided into two main groups, enamel group and cementum group (40 teeth) for each group. The enamel group was prepared with standardized Class II MOD cavity with gingival margin (1 mm above C.E.J) on both box sides. While the cementum group with the gingival margin (1 mm below C.E.J) on both sides. The enamel and cementum groups were then subdivided into eight subgroups for each (five teeth) with 10 boxes for each group. Subgroups within the main group named according to materials and techniques that were used with it as following: Amalgam subgroup (Permite, SDI), SDR subgroup (DENTSPLY) with bulk technique, Filtek™ P90 subgroup (3M ESPE) with three incremental techniques (Oblique, Horizontal and Centripetal technique), and Filtek™ Z250XT subgroup (3M ESPE) with three incremental techniques (Oblique, Horizontal and Centripetal technique).After specimens were stored in distilled water at 37°C for 7 days. All specimens were subjected to thermocycling at (5° to 55 °C). Microleakage was evaluated by stereomicroscope (20 X). Data were analyzed statistically by Kruskal-Wallis test and Mann-Whitney U-test. Result: All experimental groups showed leakage at cementum more than enamel groups. SDR bulk fill subgroup showed the highest marginal leakage among all experimental groups followed by Filtek™ Z250 XT subgroup with horizontal technique at both enamel and cementum groups. Silorane and Filtek™ Z250 XT subgroups with oblique technique showed the least marginal leakage followed by centripetal technique at both enamel and cementum groups. Amalgam restoration subgroup shows lesser leakage than SDR bulk fills subgroup significantly at both enamel and cementum groups. While it show higher leakage than Silorane subgroup with oblique technique significantly at enamel margin only. Conclusion: The limiting factors for marginal leakage are technique and material dependent.
Atomic Force Microscope is an efficient tool to study the topography of precipitate. A study using Continuous Flow Injection via the use of Ayah 6SX1-T-2D Solar cell CFI Analyser . It was found that Cyproheptadine –HCl form precipitates of different quality using a precipitating agent's potassium hexacyanoferrate (III) and sodium nitroprusside. The formed precipitates are collected as they are formed in the usual sequence of forming the precipitate via the continuous flow .The precipitates are collected and dried under normal atmospheric pressure. The precipitates are subjected to atomic force microscope scanning to study the variation and differences of these precipitates relating them to the kind of response to both precipitates give
... Show MoreThe purpose of this paper is to gain a good understanding about wake region behind the car body due to the aerodynamic effect when the air flows over the road vehicle during its movement. The main goal of this study is to discuss the effect of the geometry on the wake region and the aerodynamic drag coefficient. Results will be achieved by using two different shapes, which are the fastback and the notchback. The study will be implemented by the Computational Fluid Dynamic (CFD) by using STAR-CCM+® software for the simulation. This study investigates the steady turbulent flow using k-epsilon turbulence model. The results obtained from the simulation show that the region of the air separation behind the vehicle
... Show MoreInternational trade in services is becoming increasingly important as it is an economic activity that deals with invisible trade, which has become increasingly important in the balance of international trade. The establishment of the WTO is a starting point in international trade relations. It is responsible for all aspects of international trade, , And in view of the continued increase in international trade in services, the need for more internationally recognized rules has become more urgent, especially as it has been increasingly proven that the traditional framework of public services is inadequate to operate some of the most dynamic and innovative sectors of the economy. (GATS) to be the regulatory framework for this sector
... Show MoreThe electric quadrupole moments for some scandium isotopes (41, 43, 44, 45, 46, 47Sc) have been calculated using the shell model in the proton-neutron formalism. Excitations out of major shell model space were taken into account through a microscopic theory which is called core polarization effectives. The set of effective charges adopted in the theoretical calculations emerging about the core polarization effect. NushellX@MSU code was used to calculate one body density matrix (OBDM). The simple harmonic oscillator potential has been used to generate the single particle matrix elements. Our theoretical calculations for the quadrupole moments used the two types of effective interactions to obtain the best interaction compared with the exp
... Show MoreHydrated lime has been recognized as an effective additive used to improve asphalt concrete properties in pavement applications. However, further work is still needed to quantify the effect of hydrated lime on asphaltic concrete performance under varied weather, temperature, and environmental conditions and in the application of different pavement courses. A research project was conducted using hydrated lime to modify the asphalt concretes used for the applications of wearing (surface), leveling (binder), and base courses. A previous publication reported the experimental study on the resistance to Marshall stability and the volumetric properties, the resilient modulus, and permanent deformation at three different weather temperatures. This
... Show MoreThe electronic properties (such as energy gap HOMO levels. LUMO levels, density of state and density of bonds in addition to spectroscopic properties like IR spectra, Raman spectra, force constant and reduced masses as a function of frequency) of coronene C24 and reduced graphene oxide C24OX , where x=1-5, were studied.. The methodology employed was Density Functional Theory (DFT) with Hybrid function B3LYP and 6-311G** basis sets. The energy gap was calculated for C24 to be 3.5 eV and for C24Ox was from 0.89 to 1.6862 eV for x=1-5 ,respectively. These energy gaps values are comparable to the measured gap of Graphene (1-2.2 eV). The spectroscopic properties were compared with experimental measurements, specificall
... Show MoreThis research is studying technique sculptures super - realism, search through, how the method of work, and the search for the materials used in their manufacture, and this is the first study in the field of art and the field of academic study in the country.Research consists of an introduction, And four sections, The introduction containing information on: research problem, Importance of research, Goals of the research, Limits of research, research approach, and research tools.The first section contains a technical study sculptures super -realism in contemporary sculpture, while the second section includes a search for alternative materials available in the local markets, for making sculptures super - realism, the third section dedicate
... Show MoreA new novel series of metalcomplexes are prepared from reactions between 2-benzoylthio- benzimidazole (L) with metal salts of Co (II) , Fe(III) and Rh (III) , while Pd(II) complex was obtained by mixing ligandsof 2-benzoylthiobenzimidazole (L) as primary ligand and bipyridine (L/)as secondary ligand as well as palladium chloride as metal salt in an ethanoic medium. The geometry of these compounds were identified using C.H.N.microanalysis, Ultraviolet–visible, Fourier transforms infrared, magnetic susceptibility, molar conductivity and flame atomic absorption (A.A). From the dataobtained by these spectral analyses, the molecular structures for Rh and Fe complexes were proposed to be octahedral geometry. A square planar const
... Show MoreIn this paper, silicon carbonitried thin films were prepared by the method of photolysis of the silane (SiH4) and ethylene (C2H4) gases, with and without ammonia gas (NH3), which is represented by the ratio between the (PNH3) and (PSiH4 + PC2H4 + PNH3), (which assign by the letter X), X has the values (0, 0.13, 0.33). This method carried out by using TEA-CO2 laser, on glass substrate at (375 oC), deposition rate (0.416-0.833) nm/pulse thin film thickness of (500-1000) nm. The optical properties of the films were studied by using Absorbance and Transmittance spectrums in wavelength range of (400-1100) nm, the results showed that the electronic transitions is indirect and the energy gap for the SiCN films increase with increasing of nitrog
... Show MoreRandom laser gain media is synthesized with different types of dye at the same concentration (1×10-3 M) as an active material and silicon dioxide NPs (silica SiO2) as scatter centers through the Sol-Gel technique. The prepared samples are tested with UV–Vis spectroscopy, Fluorescence Spectroscopy, Field Emission Scanning Electron Microscopy (FESEM), and Energy Dispersive X-ray Diffraction (EDX). The end result demonstrates that doped dyes with silica nanoparticles at a concentration of 0.0016 mol/ml have lower absorbance and higher fluorescence spectra than pure dyes. FESEM scans revealed that the morphology of nanocrystalline silica is clusters of nano-sized spherical particles in the range (25-67) nm. It is con
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