Background: The demand for better esthetic during orthodontic treatment has increased nowadays, so orthodontists starting using esthetic arch wires, brackets and ligatures.Tooth colored brackets were introduced in different types of materials. Sapphire ceramic brackets are one type of esthetic brackets and their color stability remains the main concern for the clinicians and patients at the same time. The present study design to evaluate the effect of three different staining materials (pepsi, black tea and cigarette smoke) on the stainability of sapphire ceramic brackets bonded with three types of light cure orthodontic adhesives which include: Resilience, Enlight and Transbond. Materials and Methods: The sample consisted of three hundred sixty sapphire brackets. The brackets were divided according to bonding materials into three groups each group consist of one hundred twenty brackets, then each subgroup farther subdivided into four groups according to the material they were immersed (distilled water, black tea, Pepsi and cigarette smoke) with thirty brackets each, then Each group with ten brackets farther subdivided according to time interval of immersion in each media into three groups one day, seven days and fourteen days at 37°C in the incubator.A UV-Visible spectrophotometer (Shimadzu, UV -1800) was used to perform a light absorption test. Results: ANOVA and LSD post Hoc tests were used to identify the significant effects of the staining materials at a significance level P ≤ 0.05.It was found that the immersion time gradually influenced the color stability of the adhesive materials with sapphire brackets with the highest activity observed at fourteen days interval. The brackets bonded with Resilience light cure adhesive are the most type affected by staining materials, then followed by the brackets bonded with Transbond and finally the brackets bonded with Enlight light cure adhesive. For the staining materials it was found that the cigarette smoke is the most powerful staining material, followed by tea and finally pepsi. Conclusions: From the above result we can conclude that the type of adhesive must take in consideration when the esthetic brackets have been used.
To investigate the research objectives, the researchers put the following hypothesis:
There was no statistically significant difference at the level of (0.05) between the average score of the students of the experimental group who studied the language of rhetoric according to model of learning method, and the average score of the students of the control group who studied the same article in the traditional way acquiring rhetorical concept. The researchers relied on the experimental design with the partial setting of the post-test, which depends on the experimental group that is taught using the model of the learning method, and the control group taught using the traditional method.
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This research shows the history of political conflicts in Zimbabwe, the
merits of the political struggle for power in this country since the British
colonial period, especially after the British administration announced that
Zimbabwe is a local colony of the British Crown in 1923, as the settlement
process against the wide white deprive local people to own and lease land
and low income, as well as the 1961 Constitution, which granted access to
the white powers in accordance with the authority of the top menu for the
existing lower allocated to blacks.
These events and factors led to a national rejection in Zimbabwe,
which crystallized in the form of parties and political organizations through the
In this paper will be applied to a probability model of inventories periods of multiple stores of raw materials used in the cement industry, cement factory in Samawah and basic materials are limestone, soil normal, iron soil, fuel oil and gypsum. It was built of this model after the test and determine the distribution of demand during the supply period (waiting period) for each subject and independently of the rest of the material as it is not affected by any of the materials above interrelated in the process of supply, this test has been using the Statistical Package of (SPSS) and then was determining the amount of request optimum seeking in each batch and each substance known volume of economic optimization of
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The Urban Residential has developed and changed in different periods of time with successive and gradual shifts, as it cast a shadow over the characterization of modern urbanism in Iraq. The semi-total absence of the governing legislation of urbanization as well as the weakness of the State's role of supervisory in addition to neglecting urban heritage contributed in offering a strange environment in relation to its traditional identity. That was increased by the pressure of the using urban environment as a result of the increasing of population as well as the growth of people’s needs. The research aims to provide an objective view for a mechanism of the application of urban legislation to monitor the implementation o
... Show MoreA new results for fusion reactivity and slowing-down energy distribution functions for controlled thermonuclear fusion reactions of the hydrogen isotopes are achieved to reach promising results in calculating the factors that covered the design and construction of a given fusion system or reactor. They are strongly depending upon their operating fuels, the reaction rate, which in turn, reflects the physical behavior of all other parameters characterization of the system design
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Metaphor has been occupied first place among eloquent methods to build metaphors;
poetry with the latter becomes senseless thing. Metaphor is necessary part of energy that
sustains the poetry. Sentence of metaphor regarded more eloquent than the reality since it
does not conduct directly to the meaning , but rather get to it indirectly. Metaphor is
considered one of the most tools for the poet since it is a means of expression about his
sensation and feelings . Andalus paid concerns over metaphors as that being incited by their
country beauty and nature. The poet might resort to contradiction as to picture contraries
within himself.
Through pictures of contradictions depicted by the poets , it has explained that t
The placenta is an organ between the mother and fetus necessary for fetal growth and development. Gestational diabetes mellitus (DM) is the most frequent metabolic condition detected during pregnancy. It is characterized as hyperglycemia of various severity with onset or first detection during pregnancy that does not clearly describe any form of preexisting diabetes. Urotensin II (UII), a pluripotent vasoactive peptide, is important in developing insulin resistance. This study aimed to determine the level of Urotensin II(UII) in placenta and in the serum of diabetic and nondiabetic women. Methods The blood and placenta tissue collected from 50 ladies had been enrolled in this research ( 25 females with uncomplicated), (25 women with gestati
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Ephedra alata. is a plant that widely available around the world and long used in folk medicine as a natural medication, was employed in the current work to prepare extracts rich in alkaloids and to test their cytotoxic potential. Alkaloids-rich and crude extracts of E.alata were compared to pure ephedrine medication for mitosis on Allium cepa. test system. Alkaloids and crude aqueous extracts of A. cepa root tips were examined for a total of five hours at five different concentrations compared to ephedrine standard. Mitotic index, phase index, and chromosomal aberration as part of the study. IC50 values of 35 mg/ml were found for each extract, indicating a sub-lethal influence on cell viability. (Toxic and sublethal effects are thought to
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