Background: evaluate the effects of three different intracoronal bleaching agents on the shear bond strengths (SBS) and failure site of stainless steel and monocrystalline (sapphire) orthodontic brackets bonded to endodontically treated teeth using light cured orthodontic adhesive in vitro. Materials and methods: Eighty extracted sound human upper first premolars were selected, endondontically treated and randomly divided equally (according to the type of the brackets used) into two main groups (n = 40 per group). Each main group were subdivided (according to the bleaching agent used) into four subgroups 10 teeth each; as following : control (un bleached) group, hydrogen peroxide group (Hp) 35%, carbamide peroxide group (CP) 37% group and sodium perborate (SP) group . The bleaching process was applied three times (4 days intervals) sequentially and the bleached teeth were stored in artificial saliva four weeks before bonding. Orthodontic brackets were bonded with a light cure composite resin and cured with LED light. After passing 24 hours of bonding procedure, the brackets were debonded by a Tinius-Olsen universal testing machine, to measure the shear bond strength. After debonding, each bracket base and the corresponding tooth surface were examined using a stereomicroscope and their Adhesive Remnant Index (ARI) was recorded. Results: The ANOVA test showed that the SBS of stainless brackets was significantly reduced by intracorornal bleaching agents. Furthermore, LSD showed no significant difference in SBS between the three types of bleaching agents used in stainless steel group. Whilst for sapphire group, the results The ANOVA test showed no significant difference in SBS between the bleached groups and the control group. Chi-square comparison no significant difference in failure site between bleached and control groups in both brackets types used. Conclusion: The effect of intracoronal bleaching on SBS was reduced SBS of stainless steel and not for sapphire. However, the intracoronal bleaching had no effect on the failure site of orthodontic brackets used.
This study is an attempt to investigate the semantic and syntactic features of English and Arabic verbs of eating. After surveying the literature on the meaning of verbs in both languages, three chapters address the major issues in this subject. The problem to be investigated in this study can be summarized in the following points: 1. The overlapping of semantic and syntactic features within the category of verbs of eating in English and Arabic. 2. Which semantic classification is more accurate and through which method? 3. Which classification, the semantic or the syntactic, is more important? This study hypothesized the following: 1. The semantic features are more influential in analyzing the category of verbs of eating than the syntactic
... Show MoreThe activity of Adhatoda vasica crude plants extracts against B.thuringiensis bacteria was determined by MIC test and sensitivity test which showed no response of this type of bacteria against extracts .The interference between the effect of hot and cold aqueous extracts and Bacillus thuringiensis bacteria for controlling the population of fig moth when males and females released before treatment under control condithion was gave a highly percentage of larval mortality which reached to 100% in (B.t. + hot aqueous extract ) and 97.3% in (B.t + coldaqueous extract ) after two weeks of treatment when concentration of 50% of aqueous extracts and 5×10?1of Bacillus thuringiensis bacteria but when the insect (males & females) released after
... Show MoreIn the name of of Allah the Merciful
Introduction:
Praise be to Allah, Lord of the Worlds, and prayers and peace be upon our master Muhammad and his family and companions.
After
I have looked at a part of the jurisprudence of Hajj jurisprudence, which is needed now, especially after it facilitated travel to perform Hajj and Umrah, so the need was an advocate and a list for writing in it, which is beneficial to Hajj, Umrah and the guide.
And this important part is the things that contravene the woman's man in the Hajj and after the search and tracking found that there are ten things that get the violati
... Show MoreThe problem of this research is:
What are the sustainable development goals that received the priority in the press addressing of the newspapers under study?
What are the journalistic arts adopted by these newspapers in addressing the sustainable development goals?
What are the journalistic sources that Arab newspapers depended on when addressing the sustainable development goals?
What are the geographic range the Arab newspapers adopted in addressing the sustainable development goals? The research is categorized into descriptive research, adopting the survey method, and using the content analysis method.
The sample of research was determined by the preparation of the Arabic newspapers (Al-
... Show MoreThe anatomical study of the epidermis leaflet for seven species and variety wild belonging to the genus Medicago L. species are: M. constricta Dur., M. coronata L., M. intertexta L., M. intertexta.var. ciliaris L., M. laciniata L., M. lupulina L., M. minima L. and M. sativa L. were studied, The search included epidermis characters and stomatal complexes addition to venation system in leaflets. It is revealed through the study, epidermis leaflet type Amphistomatic (the stomata spread on the upper and lower surface) as well as the presence of three types of stomatal complexes namely: Anisocytic (the guard cells surrounded by three unequal cell size), Anomocytic (not differential from subsidiary cells in epidermis) and Anomotetracytic (four ce
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The leases, are regarded as one of the most controversial accounting issues in recent years, since they represents one of the important sources of funding, which may be exploited by the tenant as off- Balance sheet Financing , which negatively affects the quality of financial reporting. The Financial Accounting Standards Board (FASB) and the International Accounting Standards Board (IASB) have "significant" interest in accounting for leases . FASB issued Statement of Financial Accounting Standards 13 on lease contracts in 1976 and IASB issued IAS 17 in 1980, which was amended in 1997 and IFRS 16, issued in January 2016, which will be effective on January 1, 2019 , to solve
... Show MoreIn fish, a complex set of mechanisms deal with environmental stresses including hypoxia. In order to probe the hypothesis that hypoxia-induced stress could be manifested in varieties of pathways, a model species, mirror carp (Cyprinus carpio), were chronically exposed to hypoxic condition (dissolved oxygen level: 1.80±0.6mg/l) for 21 days and subsequently allowed to recover under normoxic condition (dissolved oxygen level: 8.2±0.5mg/l) for 7 days. At the end of these exposure periods, an integrated approach was applied to evaluate several endpoints at different levels of biological organisation. These included determination of (i) oxidative damage to DNA in erythrocytes (using modified comet assay), (ii) lipid peroxidation in liver sample
... Show MoreDr. Qahtan Al-Madfa’i’s architecture has been characterized by a particular characteristic that may be unique and extreme at the same time, that is the use of the distinctive three-dimensional structural coverings and the exploitation of structural construction to give an extra aesthetic touch to the composition of the building, to achieve the application of his universal ideas, which he strongly believed and defended.
In the period of the marked urban decline that the country undergoes now, which urges us toward making a comparison between the beginning of the modern Iraqi architecture and its ascending path up to its peak and the periods of its decline until it reached a very
... Show MoreThis research was designed to investigate the factors affecting the frequency of use of ride-hailing in a fast-growing metropolitan region in Southeast Asia, Kuala Lumpur. An intercept survey was used to conduct this study in three potential locations that were acknowledged by one of the most famous ride-hailing companies in Kuala Lumpur. This study used non-parametric and machine learning techniques to analyze the data, including the Pearson chi-square test and Bayesian Network. From 38 statements (input variables), the Pearson chi-square test identified 14 variables as the most important. These variables were used as predictors in developing a BN model that predicts the probability of weekly usage frequency of ride-hai
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