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.
The aim of this study was to measure the effectiveness of a proposed program to develop the creative abilities of the students of Tabuk University and its impact on the creative output of the NEOM project. The sample of the study consisted of (50) university students divided into two groups: an experimental group of 25 students who receive the proposed training program, and control group of (25) students.
To achieve these objectives, the researcher designed and developed tools to collect the required data, which were verified their validity and reliability.
The descriptive statistics of mean, standard deviations, correlation coefficient, T test for the associated sample were used in the analysis of the results of th
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Conflict resolution and conflict resolution
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The search for the return of economic and cultural activity and the emigration of some others
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We took the problem that we are experiencing
Menia, the holy city of Karbala in the market organization, has suffered from fierce attacks
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As well as tourism and tourism, as it depends on the abundance of visitors, tourists and residents in terms of needs and motivation
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The present paper applies Fanon Psychological reading of the problem of the Black introduced in his book Black Skin White Mask to Crooks, The black Character in John Steinbeck’s Of Mice and Men. The analysis of this character infers three essential points regarding the artistic achievement of the author. First, he uses a fictional character that offers a psychological interpretation of the black problem of alienation and loneliness in a way that does not disgrace the black. Second, he applies Fanon’s way of showing the various attitudes that the black adopts in contact with the white society. Third, he affirms that the black inferiority complex comes as a result of double proc
... Show MoreWhat is meant by objectives: the purpose, secrets, judgment, and interests that the legislator set for each of its rulings is a doctrine and a law.
Faith is belief with certainty in God Almighty, and what is required of him in his divinity, lordship, names and attributes, belief in his angels, books, messengers, the Last Day and destiny, both good and bad.
And the purposes of faith are the wisdom and secrets contained in the Islamic faith and which achieve human well-being and happiness in the immediate and the future. And that the purposes of belief and faith are the essence of religion, rather it constitutes a basic pillar on which the basis of the intentional consideration as a whole, because the structure of worship i
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The multiple linear regression model of the important regression models used in the analysis for different fields of science Such as business, economics, medicine and social sciences high in data has undesirable effects on analysis results . The multicollinearity is a major problem in multiple linear regression. In its simplest state, it leads to the departure of the model parameter that is capable of its scientific properties, Also there is an important problem in regression analysis is the presence of high leverage points in the data have undesirable effects on the results of the analysis , In this research , we present some of
... Show MoreThis study presents determination of the paleostress magnitudes and orientation of Bekhme Structure in Shaqlawa area northeastern Iraq. Paleostress Analysis of slip-fault measurements is performed using Right dihedral, Lisle diagram and Mohr Circles methods. Depending on Mohr Circles, Bott law and vertical thickness, the magnitudes of the paleostress at the time of the tectonic activity were determined. Firstly, Georient Software was used to estimate the orientation of the paleostresses (σ1, σ2 and σ3). Secondly, using the rupture –friction law, taking into account depth of the overburden and the vertical stress (σv) was calculated to determine the magnitude of the paleostresses (σ1=4500 bars, σ2=1
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the reality of small and medium enterprises analysis reflects weaknesses plaguing these enterprises and strengths that are characterized by, and thus the formulation of appropriate solutions to the obstacles faced by these enterprises to enhance its contribution to the achievement of economic and social development. Iraqi small and medium enterprises suffer from several obstacles stand in front of development and support their competitiveness, the finance one of the main obstacles which impede growth and development of these enterprises, noting the banking system in Iraq reluctance to lend to small and medium-sized enterprises, as a result of the high cost of lending these enterprises compared to large projects, as well as
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