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.
The energy expectation values for Li and Li-like ions ( , and ) have been calculated and examined within the ground state and the excited state in position space. The partitioning technique of Hartree-Fock (H-F) has been used for existing wave functions.
This review is concluded of 8-Hydroxyquinline (8HQ) compound and derivatives which has a very significant interests with a strong fluorescence , furthermore the relationship between divalent metal ions and characteristic of chelating . In the same way coordinated features have increase of its organic action and inorganic behavior by giving many samples of compounds which are a good chelating agents ligands with more capable of forming very stable complexes.Therefore, the role of (8HQ) is not limited on complexes only but its applications in different fields so this review will focus on demonstration preparation methods and properties of (8HQ) derivatives with their complexes and applications, hopefully that we will cover a part of scientifi
... Show Moreيشكل السياق جانبا مهماً في فهم الخطاب والمقصود هنا العرض المسرحي، من خلال ما يمده السياق للمتلقي من مؤشرات، يتم الاعتماد عليها في استكمال المعنى الظاهر بالمعنى المستتر، فالسياق يعتمد في الاصل على المحيط المادي الاجتماعي الذي يتم فيه التواصل وفيه يتعرف المرسل والمتلقي أحدهما على الآخر وتتبلور الصورة التي يحملها الطرفان أحدهما عن الآخر، الى جانب كونه يمثل الاحداث التي سبق لهما أن عاشاها والتبادل القولي
... Show MoreEmploying the social personalities (celebrities) in all fields (artistic, sports, media, etc.) is an important media and visual communication means of identification for the companies and institutions in order to convey the advertising idea in accordance with the creative, aesthetic and functional principles aimed at promoting products and gaining the symbolic value for the company. This study investigates the employment of social personalities in the commercial advertising design in order to pinpoint the importance of employing celebrities and their representation in the advertisement to convey the meaning that signifies the advertisement goal. Thus the question of the study is: "What are the mechanisms of employing celebrities in the d
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Phonological metathesis can be defined as an alternation in the normal sequence of two sounds under certain conditions. The present paper is intended to give a detailed synchronic description of phonological metathesis in Iraqi Arabic dialect. For data collection, the researchers have adopted two naturalistic techniques, viz., observation and notes taking. A synchronic analysis is carried out to provide some evidence that describe the sequential change of phonological metathesis in the dialect under investigation. Such sequential changes of metathesized sounds are presented and tabulated. The study concludes with the following finding that this process is not limited to cases where two consonant sounds are transposed, but three consonant
... Show MoreThe oil sector in Iraq suffered from several difficulties led to the decline and reduction of oil production and the deterioration of refineries and transport pipeline status in addition to the weakness of the technology side and the prevalence of financial and administrative corruption besides the high costs of rehabilitation of the oil sector and also administrative and institutional problems still ongoing.
In spite of Iraq's possession of vast oil wealth allows him to play an important role in the international energy market، he is still under the level. The production of oil doesn'<
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Abstract The relative pronoun in Hebrew language is an important pronoun use anciently and recently, it developed and it's usage and meanings differed so, it was not confined to the particle "אֲשֶׁר" as a relative pronoun, but beside it appeared other pronouns giving the relative meaning. Hence, the topic of this research was on this basis through studying the relative pronouns in old and modern Hebrew, the way of using them and their connection with preposition particles, as well as studying the relative clause.
