Objective: Evaluate the effects of different storage periods on flexural strength (FS) and degree of conversion (DC) of Bis-Acryl composite and Urethane dimethacrylate provisional restorative materials. Material and Methods: A total of 60 specimens were prepared from four temporary crown materials commercially available and assigned to four tested groups (n = 15 for each group): Prevision Temp, B&E CROWN, Primma Art, and Charm Temp groups. The specimens were stored in artificial saliva, and the FS was tested after 24 h, 7 d, and 14 d. A standard three-point bending test was conducted using a universal testing machine. Additionally, the DC was determined using a Fourier transform infrared spectroscopy (FTIR) device. The data were analyzed statistically using two- way ANOVA, Tukey`s HSD post-hoc test, and the Bonferroni test, all at a 5% significance level. For each group, a paired samples test was applied to compare the DC of the immediate and 24 h samples. Results: The highest FS value was found for the Prevision Temp material, while the Charm Temp material showed the lowest FS, with no statistically significant difference between the mean values of the groups at 24 h; while there were significant differences at 7d and 14 d of storage. However, within each group, the aging had no significant impact on the FS, except for an increase in the FS of the B&E CROWN group after 14 d. Prevision Temp also had the highest mean DC value. At each time interval, significant differences were recorded. Moreover, within each group of material, aging significantly increased the DC, except for the Primma Art. Conclusion: Bis-acryl composite resin materials exhibited higher flexural strength compared to traditional methyl methacrylate resin during the 14 d investigation period. Aging in artificial saliva did not significantly affect the mechanical performance of the tested materials. Materials with higher DC values showed greater flexural strength; where the Prevision Temp showed higher FS and DC values than the other tested materials.
Background: The miswak is a teeth cleaning twig made from a twig of the Salvadora persica tree (known as arak in Arabic).A traditional alternative to the modern toothbrush, it has a long, well-documented history and is reputed for its medicinal benefits. It also features prominently in Islamic hygienical jurisprudence. Materials and methods: Twenty maxillary first premolars were treated with the selected solutions which included siwak water extract (5%, 10%) and sodium fluoride 0.05% for 2minutes once daily for 20 days interval, deionized water was used as control negative. Then the concentration of the dissolved calcium ion in the etching solution of 2N HCL was measured. Results: The least amount of the dissolved calcium ion was registere
... Show MoreBackground: The marginal fit is the most characteristic that closely related to the longevity or success of a restoration, which is absolutely affected by the fabrication technique. The objective of present in vitro study was to evaluate the effect of four different CAD/CAM systems on the marginal fit of lithiµm disilicate all ceramic crowns. Materials and Methods: Adentoform tooth of a right mandibular first molar was prepared to receive all ceramic crown restoration with deep chamfer finishing line (1mm) and axial reduction convergence angle of 6 degree, dentoform model duplicated to have Nickel-Chromiµm master die. Thirty two stone dies produce from master die and distributed randomly in to four groups (8 dies for each group) accor
... Show MoreAnchusa strigosa - prickly alkanet from Boraginaceae grows in roadsides, and fields of a broad range of habitats from mediterranean woodlands, to steppe vegetation, to true desert. It is commonly known as" him him" or "lisan al thawr". Anchusa can withstand hard weather conditions and hence is widely cultivated. The color of its flowers can range from pure white to deep cobalt blue. Various parts of A. strigosa are used in traditional medicine for treating several diseases or symptoms, such as abdominal pain, bronchitis, cough, and diarrhea. The goal of this study was to examine the cytotoxic effect of the crude extract of A. strigosa roots and leaves and their fractions against various tumor cell lines: adenoc
... Show MoreSynthesis of PEG 200-Di- Acetate ant Its Influence on the Viscosity of PEG 4000 in Different Organic Solvents
Anodic electrodeposition was used to synthesize a composite electrode of nanostructured manganese dioxide/carbon fiber (CF) galvanostatically. Different characterization results of the nanostructured MnO2 were obtained by varying the H2SO4 concentration and the current density. Field emission scanning electron microscopy, X‐ray diffraction, and atomic force microscopy were utilized to characterize the prepared composite electrodes. The best conditions were: 0.3 mA cm−2 current density and 0.64 M H2SO4 concentration. The electrosorption performance of the MnO
Insurance Companies perform a prominent role in providing services and bolstering national economy, and they contribute in achieving the aims of the economic development plans in addition to many other social and economic benefits. So it is necessary to evaluate the activity of these companies continuously to define performance level and its nature. Financial analysis is one of the important instruments that helps in analyzing and explanation of data in such a way that enable administration to define performance level and diagnosing strength and weakness points. This study tackles the state of affairs of the Iraqi Insurance Company which is considered as one of the active national institutions, due to its distinguished role in collecting
... Show MoreThe measurement of minority carrier lifetime (MCLT) ofp-n Si fabricated with aid of laser doping technique was reported. The measurement is achieved by using open circuit voltage decay (OCVD) technique. The experiment data confirms that the value of MCLT and proftle of Voc decay were very sensitive to the doping laser energy.
Abstract his study involved evaluation of side effects of two weight reduction pills that had been widely distributed in the last period. Two weight reduction compounds are studied, Reductil (containing chemical substances) and Chinese’s weight reduction herbs (containing natural substances). Two doses for each compound are used in this research; 5mg/ml and 0.5mg/ml for Reductil, while 30mg/ml and 10mg/ml for Chinese weight reduction herbs. To evaluate the toxic effects of these compounds, the following parameters were determined which include mitotic index (cytogenetic analysis), serum FSH and LH hormones level (follicles stimulation hormone/FSH and lutenising hormone/LH) and histological examination of female mice ovaries. Control group
... Show MoreA new tool geometry was used to achieve friction stir spot welding (FSSW) in which the shoulder was designed separately from the rotating pin, and in order to examine weldment strength through the modified tool, a lap joints of AA2024 aluminum alloy plate 1 mm thick were welded successfully by using 6 mm pin diameter and varying process parameters (rotational speeds, tool nose geometry, and depth of tool penetration in the lower welded plate). Experimental tests indicate that the maximum average tensile shear load was 3100 N at the best selected condition. Microstructure examination and micro hardness test along the spot zones were investigated as well as measuring pin penetration load. Visual inspection of the welded spot surface shows a g
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