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.
The increase in the Iraqi population put pressure on urban cities as there were no new cities built since the 1980s due to the wars and the economic blockade imposed in 1991 and the deteriorating security situation after 2003, where the population in 2018 reached about forty million people. Iraq also suffered during the past decades from problems and challenges in many respects that affected the local environment, and the constructed buildings had a role in increasing these impacts, so the Ministry of Housing worked to issue the Iraqi Green Architecture Code in 2019 to reduce damage to the environment and use resources more efficiently. And because the constructed buildings were not constructed according to green standards, including Bas
... Show MoreInsurance companies seeking to develop programs to promote and market their services and to increase its customer through the use of modern technical marketing and reduce its dependence on agents and take advantage of work of the banks by alliances with them and including reinforcing get the parties to competitive advantages in the financial market , the insurance services intangible service stops marketed over the insurance awareness and requires exceptional promotional efforts. &nbs
... Show MoreDuring of Experimental result of this work , we found that the change of electrical conductivity proprieties of tin dioxide with the change of gas concentration at temperatures 260oC and 360oC after treatment by photons rays have similar character after treatment isothermally. We found that intensive short duration impulse annealing during the fractions of a second leads to crystallization of the films and to the high values of its gas sensitivity.
الخلفية: التهاب المفاصل الرَثَيَانِي أو الداء الرثياني أو الالتهاب المفصلي الروماتويدي هو مرض مزمن، من الأمراض الانضدادية التي تؤدي بالجهاز المناعي لمهاجمة المفاصل، مسببة التهابات وتدميرًا لها. ومن الممكن أيضًا أن يدمر جهاز المناعة أعضاء أخرى في الجسم مثل الرئتين والجلد. وفي بعض الحالات، يسبب المرض الإعاقة، مؤدية إلى فقدان القدرة على الحركة والإنتاجية. ويتم تشخيص المرض بواسطة تحاليل دم مخبرية مثل تحلي
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Benign prostatic hyperplasia (BPH) is one of the most common disease and major cause of morbidity in elderly men which may lead to bladder outflow obstruction and lower urinary tract symptoms (LUTS). Although sex steroid hormones play fundamental roles in prostate growth, their clinical significance is not completely clear. In the present study we assessed whether serum hormones levels as markers of prostate disease. This study includes (40) patients with benign prostatic hypertrophy and (40) control group with age rang (41-79) and (42-71) years respectively. The following biochemical investigations have been studied: Testosterone, Estradiol (E2), and Prostatic Specific Antigen (PSA) levels using ELISA method which correlated with t
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Testing the current research and effect correlation between Transformational leadership variable manufacturing and variable administrative creativity, as it represented the research problem the extent of the role of transformational leadership in achieving administrative creativity in the office of the Iraqi Ministry of Education, it has been used questionnaire as a tool for data collection, as is the distribution (32) for the sample of the research, which was selected intentional and as director general and assistant general manager and director and deputy director and head of the Division, and represented the premise of the major search existence of liaison and the impact of significantly between transformational leadership and achieve
... Show MoreThe study aims to show the correlation between inflation rates and the volume of private sector deposits in Jordan on one hand, and Amman Stock Exchange index for the period of 1999-2017. The study used the “Vector Auto Regression” model. Different types of tests are used such as: The “Johansen Co integration” test of joint integration, “Granger causality” test, the “Analysis of Variance Decomposition”, and “Impulse response Function” test.
The results showed there is a positive-one-way causal effect from Amman Stock Exchange index to inflation. Also, a one-way causal effect that comes from Amman Stock Exchange index to the size of private sec
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