objective: To evaluate the influence of monolithic zirconia brand, thickness, and substrate color on color matching accuracy when optically coupled to abutment substrates. Methods: A total of 180 samples of two brands of monolithic zirconia [Prettau Anterior (PA), Ceramill Zolid FX Multicolor (CZ)] were prepared in three different thicknesses (0.8 mm, 1.5 mm, and 2 mm) with a standardized 10 mm diameter. Color properties of the samples were assessed using spectrophotometry at baseline and after coupling to three substrate types: standard dentin, discolored dentin, and titanium. Color differences (ΔE) were calculated and statistically analyzed by 3-way ANOVA and pairwise comparison ( α=0.05). Results: The brand and material thickness, at baseline and after coupling to different substrate colors, had significant effect on color variations (P < 0.001). CZ consistently exhibited higher color differences than PA across all conditions. Thinner specimens (0.8 mm) demonstrated greater sensitivity to substrate color, and increasing the thickness to 1.5 mm resulted in a reduction in color differences, particularly for CZ formulations. Thinner zirconia restorations (0.8 mm) require careful material selection and substrate matching to mitigate perceptible color shifts. Conclusion: The accuracy of color matching of monolithic zirconia restorations is significantly influenced by material composition, thickness, and underlying substrate color. CZ demonstrated greater substrate transparency effects compared to PA, emphasizing the critical role of material selection in clinical outcomes. Clinical significance: Clinicians should carefully consider the potential change of the color properties of monolithic zirconia restorations, especially in thin sections and with dark tooth substrate, when color masking is needed.
Several types of laser are used in experimental works in order to study the effects of laser on blood vessel. They differ from each other by a lot of properties mainly in wavelength, energy of the laser and pulse duration. In this study argon laser (488 nm- 514 nm) and continuous Nd: YAG laSer (1064 nm), have been applied to 50 samples of sheep blgod tesselS. Histologically, tha results of the study were different According to the txpe of L`sar used; apgon larer had distrabtave effects on $he blood vessal while continuous Nd: YAG laser Appeaped to be the safesd one on the blmod vessel architecture. This study concluded that argoj laser has da-aging ef&ect on
... Show MoreBasil (Ocimum basilicum L.), a leafy plant used for fresh food, medicinal purposes, and aromatic purposes (including the extraction of volatile essential oil and active compounds), was the subject of a worker experiment at the College of Education for Pure Sciences Ibn Al-Haitham / University of Baghdad during the 2023 growing season. The experiment aimed to determine the effects of spraying the basil plant’s vegetative system with aqueous extracts of watercress and parsley on the plant’s growth characteristics and the production of active compounds. The experiment included two factors, the first factor, the aqueous extract of the watercress plant in three concentrations (0, 5, 10
A polycrystalline PbxS1-x alloys with various Pb content ( 0.54 and 0.55) has been prepared successfully. The structure and composition of alloys are determined by X-ray diffraction (XRD), atomic absorption spectroscopy (AAS) and X-ray fluorescence (XRF) respectively. The X-ray diffraction results shows that the structure is polycrystalline with cubic structure, and there are strong peaks at the direction (200) and (111), the grain size varies between 20 and 82 nm. From AAS and XRF result, the concentrations of Pb content for these alloys were determined. The results show high accuracy and very close to the theoretical values. A photoconductive detector as a bulk has been fabricated by taking pieces of prepared alloys and polished chemic
... Show MoreIraqi EFL college instructors, who supervise the teaching practice of EFL student teachers, commonly experience the inefficient teaching performance of prospective teachers. This inefficiency is usually due to their inability to make connections between the practical experience and the theoretical knowledge of TEFL. One of the reasons behind this inability may be the employment of traditional ways of training and instructing student teachers. Moreover, it is usually noticed that many Iraqi EFL student teachers have a negative attitude toward the teaching profession. They explicitly state that they would join the teaching force only if they fail to work in any other field.
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The study aimed to identify the expansion in granting credit to Iraqi banking institutions and its impact on the financial position of Iraqi banks in terms of revenues, profits, expenses and property rights in banks, as the expansion in granting bank credit will correspond to an increase or decrease in some items of the balance sheet and the financial position of banks, so the problem of the current study It will be determined through whether the expansion of granting bank credit will affect the financial position of Iraqi banks or not by studying the selected research community of the 10 Iraqi banks listed in the Iraq Stock Exchange, The research sample included the u
... Show MoreThis work presents a five-period chaotic system called the Duffing system, in which the effect of changing the initial conditions and system parameters d, g and w, on the behavior of the chaotic system, is studied. This work provides a complete analysis of system properties such as time series, attractors, and Fast Fourier Transformation Spectrum (FFT). The system shows periodic behavior when the initial conditions xi and yi equal 0.8 and 0, respectively, then the system becomes quasi-chaotic when the initial conditions xi and yi equal 0 and 0, and when the system parameters d, g and w equal 0.02, 8 and 0.09. Finally, the system exhibits hyperchaotic behavior at the first two conditions, 0 and 0, and the bandwidth of the chaotic
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