Aim: To evaluate the effect of two bonding systems and two curing systems on sealing ability of class V composite restorative materials. Materials and methods: This study was performed in vitro on 40 caries free upper first premolar teeth. The Standardized class V cavity preparation on buccal and lin- gual surfaces of each tooth was done. Then the teeth were randomly divided into two major groups each of twenty. 40 cavities were performed on these teeth and the first group7th generation bonding agent (i Bond) were applied according to the manufacturer instructions and single increment of univer- sal composite (XRV Herculite) from kerr were applied and twenty of the cavities were cured with con- ventional light cure device (astralis-5) and the other twenty cavities were cured with a LED. While the second group 5th generation (Excite bonding agent) applied according to the manufacturer instructions. And filled with universal composite (tetric).Twenty of the cavities light cured with conventional light cure device and the other twenty cavities cured with LED light cured device. Then the teeth were stored in normal physiological saline in an incubator at (37Co) half of each sub group (10 cavities) were stored for one day and the second half stored for one week. Then the teeth were thermo cycled for (200) cycles, after thermo cycling all teeth were immersed in a freshly prepared solution of 2% methylene blue for (24) hours at (37Co). Results: The results showed that there was no statistically significant difference between samples cured using conventional light curing system and those cured using LED light curing system. The type of bonding system and composite material used in this study had no sig- nificant effect on reducing microleakage. Samples aged for seven days produced significantly higher levels of microleakage than that for one day. Conclusions: All samples in this study showed microlea- kage with different levels. Microleakage increases as the age increases. Neither the types of light curing system nor the types of bonding were able to reduce microleakage.
Glass Ionomer Cement (GIC) is one of the important dental temporary filing materials. The aim of this study is to evaluate the effect of adding 3, 5 and 7 wt. % of TiO2 microparticles to conventional GIC powder (Riva Self Cure) on mechanical properties and its effect on absorption and solubility processes. TiO2 particles additives improved compressive strength and biaxial flexural strength, where the compressive strength increased with increasing in the added ratio, while the highest value of the biaxial flexural strength was at 3 wt.%. The addition of TiO2 particles improved the surface Vickers microhardness values, with highest value at 5 wt. %. On other hand TiO2 addition im
... Show MoreBackground: Hypothyroidism is the most abundant thyroid disorder worldwide. For decades, levothyroxine was the main effective pharmacological treatment for hypothyroidism. A variety of factors can influence levothyroxine dose, such as genetic variations. Studying the impact of genetic polymorphisms on the administration of medications was risen remarkably. Different genetic variations were investigated that might affect levothyroxine dose requirements, especially the deiodinase enzymes. Deiodinase type 2 genetic polymorphisms’ impact on levothyroxine dose was studied in different populations. Objective: To examine the association of the two single nucleotide polymorphism (SNP)s of deiodinase type 2 (rs225013 and rs225014) and le
... Show MoreThis study offers the elastic response of the variable thickness functionally graded (FG) by single walled carbon nanotubes reinforced composite (CNTRC) moderately thick cylindrical panels under rotating and transverse mechanical loadings. It’s considered that, three kinds of distributions of carbon nanotubes which are uniaxial aligned in the longitudinal direction and two functionally graded in the transverse direction of the cylindrical panels. Depending on first order shear deformation theory (FSDT), the governing equations can be derived. The partial differential equations are solved by utilizing the technique of finite element method (FEM) with a program has been built by using FORTRAN 95. The results are calculat
... Show MoreThe objective of this work was to determine and compare the physiological changes in some: blood components (packed cell volume and hemoglobin) and plasma biochemical parameters (glucose, total protein, albumin, cholesterol and triglycerides) under 3 day of different types of stress: water deprivation, starvation, overcrowding and handling stress. Twenty five male Wister rats weighted 100-120 gm, were divided randomly into five groups: control, water deprivation, starvation, overcrowding and handling stress. On the third day of stress the animals anesthetized for blood collection; the results of blood component revealed a significant increase in PCV and a significant decrease in Hb of water deprivation group and starva
... Show MoreThe corrosion inhibition of low carbon steel in1N HCl solution in the presence of peach juice at temperature (30,40,50,and 60)°C at concentration ( 5, 10, 20, 30, 40and 50 cm3/L)were studied using weight loss and polarization techniques. Results show that the inhibition efficiency was increased with the increase of inhibitor concentration and increased with the increase of temperature up to 50ºC ,above 50ºC (i.e. at 60 ºC) the values of efficiency decreases. Activation parameters of the corrosion process such as activation energies, Ea, activation enthalpies, ΔH, and activation entropies, ΔS, were calculated. The adsorption of inhibitor follows Langmuir isotherm. Maximum inhibition efficiency obtained was a bout 91% at 50ºC in the
... Show MoreThe aqueous extract of banana fruits peal was tested for its effect on mitosis . The root tips of Allium cepa were used as plant test system and the bone marrow cells of the albino mice Mus musculus were used as mammalians test system in vivo .Root tips of Allium cepa were treated for four hours with five concentrations of the extract (5 , 10 , 20 , 40 ,60 mg / ml.).The Metaphase was arrested in all the treatments , the highest percentage ( 100 % ) was recorded in the first concentration , the last concentration caused stickiness and clumping of the chromosomes. The treatments did not cause significant difference in the mitotic index. The peals extract (5 mg /ml) was compared with the extracts of fruits bulb, leaves and roots of
... Show MoreBackground: Hypothyroidism is the most abundant thyroid disorder worldwide. For decades, levothyroxine was the main effective pharmacological treatment for hypothyroidism. A variety of factors can influence levothyroxine dose, such as genetic variations. Studying the impact of genetic polymorphisms on the administration of medications was risen remarkably. Different genetic variations were investigated that might affect levothyroxine dose requirements, especially the deiodinase enzymes. Deiodinase type 2 genetic polymorphisms’ impact on levothyroxine dose was studied in different populations.
Objective: To examine the association of the two single nucleotide polymorphism (SNP)s of deiodinase t
... Show MoreAim: To evaluation the effect of Lactobacillus acidophilus on Enterohemorrhagic Escherichia coli (EHEC) serotype O157:H7 with detection of some virulence factors. Methods: Two hundred and fifty specimens (stool) from children under five years for both sexes were collected from some hospitals. All isolates were diagnosed according to morphological characteristics, biochemical tests. Monoplex pattern of PCR was used also for detection different genes in (7) Escherichia coli )O157:H7 (isolates; include 16SrRNA, eae, lifA, Stx1,Stx2 that encoded for ribosomal RNA, intimin, lymphocyte inhibitory factor, shiga toxins. Three types of probiotics strains were obtained, Lactobacillus fermentum, Lactobacillus plantarum and Lactobacillus acidophilus (A
... Show MoreIn this work, the effect of anodizing duration on the morphology and photoelectrochemical properties of TiO2 nanotubes arrays (NTAs) has been investigated The samples were characterized by X-ray diffraction (XRD) and energy dispersive X-ray (EDX) to characterize their crystalline structure and compositional. Surface morphological and their dimensional variation was examined by field emission scanning electron microscopy (FESEM). The anodizing duration played a significant role in the formation of TiO2 nanotubes arrays. Moreover, the photoelectrochemical properties (PEC) were studied through photocurrent measurements. Optimum anodizing duration of 60 min at 40 V exhibited maximum photocurrent of 0.03 mA cm-2 under illumination of hal
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