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.
Autorías: Mariam Liwa Abdel Fattah, Liqaa Abdullah Ali. Localización: Revista iberoamericana de psicología del ejercicio y el deporte. Nº. 4, 2023. Artículo de Revista en Dialnet.
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The current research aims to answer the following questions: what is the substance of democracy? What is the content of a democratic society? What is the role of university professor in the democratic development of the student university in light of the new Iraqi society? In order to achieve the goals of the research, the researcher developed an a questionnaire based on literature, Iraq's draft constitution in 2005, and his experience of the field of teaching human rights and public freedoms and the teaching of democracy. It was applied to a sample of faculty members in Department of Education and Psychology / College of Education / University Baghdad for the year 20014 were obtained their answers were then processed statistically. Henc
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The current research aims to reveal the reality of coping the scientific research in Omani universities in the Sultanate of Oman with the requirements of the Fourth Industrial Revolution in the light of Oman’s 2040 vision. It also aims derive some suggestions to develop the scientific research in these institutions. The study has adopted a qualitative approach in which interviews were conducted. The sample consisted of (16) leaders of governmental and private higher education institutions, as well as, some experts in the field of Fourth Industrial Revolution. The theoretical significance of the study is represented by its response to Oman’s vison in 2040. It is further in line with the previous international reports and educational s
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A study carried out for study effect of furfural that extracted from corn cobs by using specialized reaction system laboratory on phytopathogenic fungi: Pythium aphanidermatum, Rhizoctonia solani, Macrophomina phaseolina and Fusarium solani in addition to biocontrol fungus Trichoderma viride were isolated from infected plants and from their rhizosphere . The preparation results of different concentrations from stock solution in concentration 1% of furflural showed that The concentration was 100 ppm of furfural was inhibited the growth of P. aphanidermatum46.7 % and the was in concentration 400 ppm. while the concentration 500 ppm caused inhibition 50% and 41.1% of R. solani and F. solani respectively. Whereas the concentration 500 pp
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Many changes took place in a number of Arab countries, most of which ended with the change of the ruling leadership and a new coming. The same change brought about the hopes of the people to turn the page of the past into a democracy through which to overcome the grievances of previous years and achieve justice in all its aspects. The same new grievances have been added to that precedent and justice has not yet been achieved. Here we try to address the justice that is applied in the stages of change or transitional stages, which have been called, ie transitional justice, which has mechanisms and conditions of different application between countries, each of which the conditions applied in them and through a review of these mechanisms bet
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Background: Decontamination of gutta percha cones was important factor for success of root canal treatment. The aim of the present in vitro study was to identify and to compare the antimicrobial effect of following disinfection solutions: 0.2% chlorhexidine gluconate, Iodine, tetracycline hydrochloride solution, EDTA & formocresol mixed with zinc oxide eugenol, on E faecalis, E coli and Candida albicans using sensitivity test Materials and Methods: Three types of microorganisms were isolated from infected root canals (E faecalis, E coli and Candida albicans) and cultured on Mueller Hinton agar petri-dishes. Disinfection of gutta percha cones done by immersion in six disinfection solutions (six groups), the groups are: distill water (used a
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