Background: Thermocycling simulates the temperature dynamics in the oral environment. This in vitro study done to measure and compare the effect of thermocycling on the shear bond strength of stainless steel and sapphire brackets bonded to human enamel teeth using light cured orthodontic adhesive and debonded at various time, and to measure adhesive remnant index after debonding. Materials and Methods: one-hundred-twenty extracted upper first premolars for orthodontic reason were used in this study; depending on weather thermocycled or not, the sample was divided into two main groups, then within each group 30 teeth were used for stainless-steel brackets (Bionic®) and for sapphire brackets (Pure®). Both groups were subdivided into three groups (n = 10) according to the debond times: I: debond after 24 hour, II: debond after 7 days and III: debond after 30 days. Within 24 hr, half of the sample was thermocycled manually for 500 complete cycles between 5/55°C and the remaining sample was stored in distilled water at room temperature and water was changed daily until debond time for each group was performed. The adhesive remnant index was tested under 20X magnification lens using stereomicroscope. Results and Conclusions: Both bracket types demonstrated high shear bond strength values before thermocycling (P?0.05), whereas after 500 thermocycles, there were significant changes in shear bond strength resulted in marked reduction in the stainless steel brackets than in the sapphire brackets (P?0.05). Shear bond strength values increased with time for both stainless steel and sapphire brackets with and without thermocycling (P?0.05). The tendency of bond failure was increased at the bracket/adhesive interface rather than enamel/bracket interface in the stainless steel brackets whereas at the enamel/bracket interface rather than bracket/adhesive interface in the sapphire brackets.
With the twenty - First century, It becomes clear to us that for 110 years the Japanese - Chinese relations have been witnessing big radical events and developments. ( we take the year of 1949 as the starting date for this relations). In order to prove hypothesis the study divided in to four chapters. - The first chapter deals with explaining the factors of the subject of the Japanese - Chinese relations which described as Indirect threat and aggressive relations from Japan to China after the Second World War by Japanese entering in the American world strategy, in order to destroy the communist china's system which decleard in 1949, because the united states understood that the new system in Beijing could threat American's Interest
... Show MorePraise be to God, Lord of the worlds, and prayers and peace be upon our master Muhammad and upon his family and companions.
And after:
Muslim scholars have fought in the extent of regard to these interests, each according to his opinion and according to his evaluation, and his consideration of this interest, but it remains important that the legislation in them needs more precaution and caution against the predominance of passions, because the passions often decorate spoilers so they see an interest, so practical application must To realize the spirit of Islamic Sharia in its entirety of its rulings, and the preponderance between the interests and evils that prevail in our societies, which c
... Show MoreJudaism followed the approach of monotheism after God Almighty sent Moses (peace be upon him) to convey to them the messages of their Lord, so that they might be on a right guidance and path, but the people did not follow that path.” Love of matter and faith in what is witnessed, so they portrayed the Lord in several images in line with what their souls drew upon them.
The achievement of world peace is a humanitarian demand that humanity has sought since its existence. Despite the international and regional efforts to achieve this demand, it is still reaching its desired ambitions if conflicts, contradictions, and internal and external wars continue to justify us clearly in terms of ethnic, religious and sectarian conflict. The revolution of informatics and the impact of globalization opened a new era of communication and openness and the negative and positive impact of others, which re-published and distributed values, ideas and new cultures Some of them carries extremist ideas urging violence and destruction and other abolition, it became necessary to follow policies and reward The culture of peace,
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Experimental work from Magnetic Abrasive Finishing (MAF) tests was carried out design parameters (amplitude, and number of cycle which are formed the shape of electromagnetic pole), and technological parameters (current, cutting speed, working gap, and finishing time) all have an influence on the mechanical properties of the surface layer in MAF process. This research has made to study the effect of design and technological parameters on the surface roughness (Ra), micro hardness (Hv) and material removal (MR) in working zone. A set of experimental tests has been planned using response surface methodology according to Taguchi matrix (36) with three levels and six factors
... Show MoreThe necessity of addressing global economic prosperity has garnered significant attention from recent studies and policymakers. This article analyses the effects of the digital economy, business synergies, and trade policies on the economic prosperity of China and India. The study examines the impact of political support on the digital economy, business synergies, trade policies, and global economic prosperity in China and India. The study collects data from prominent economists in India and China using questionnaires. The article utilised the SPSS-AMOS software to analyse the relationship between variables. The results showed that the digital economy, business synergies, and trade policies are positively linked to global economic prosperit
... Show MoreThis study aims to identify the teaching problems that teachers of students with intellectual disabilities face, in addition to exploring the solutions suggested by them in order to overcome such problems or challenges. The researchers used a qualitative approach in order to understand the teachers' perceptions about these problems in a more in-depth way. The interview tools (in-depth and semi-structured interviews) were used to collect data from (3) female teachers from special education programs in the Asir region. The results revealed a number of themes including problems related to students, teachers and the teaching methods they use, curricula, school environment, and school administration. Moreover, the results indicated that famil
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The prevention of bankruptcy not only prolongs the economic life of the company and increases its financial performance, but also helps to improve the general economic well-being of the country. Therefore, forecasting the financial shortfall can affect various factors and affect different aspects of the company, including dividends. In this regard, this study examines the prediction of the financial deficit of companies that use the logistic regression method and its impact on the earnings per share of companies listed on the Iraqi Stock Exchange. The time period of the research is from 2015 to 2020, where 33 companies that were accepted in the Iraqi Stock Exchange were selected as a sample, and the res
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