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 results of the current study showed that the thyroid gland in adult domestic cat (Felis catus) is located in the neck area on both sides of the trachea at rings (1-5). The gland consists of two lobes (right and left) and it is surrounded by a capsule of connective tissue consisting of two outer and inner layers, and a layer of fatty tissue overlaps with the outer layer of the capsule. In addition, the results of this study found that the histological structure of the thyroid gland is composed of several follicles that appear in different sizes and shapes; the follicles are lined with simple cuboidal epithelial tissue and sometimes appear lined with high and low simple cuboidal epithelial tissue. The gland is histologically composed of t
... Show MoreBackground Birth defects are one of the causes of pediatric disability and mortality in all around the world. Data on birth defects from population-based studies originating from developing countries are lacking. Cleft lip (CL), cleft lip and palate (CLP), and isolated cleft palate (CP), collectively termed oral clefts, occur in all races, both sexes, and all socioeconomic groups and vary internationally (1). The main aim of this research is to establish the frequency of cleft lip and/or palate in the population of the Al-Ramadi City, and to characterize the demographic features of affected individuals and find possible risk factors. Materials and methods We conducted a survey of the Educational Maternal and Pediatric Hospital in Al-Ramadi
... Show MoreThe objective of this study was to investigate and compare among five different methods of contraception including combined oral contraceptive pills (COC), Depot medroxyprogesterone acetate (DMPA), copper Intrauterine contraceptive device (IUCD), vaginal spermicides and male condom used in Hawler City through estimate of their effect, relative failure rate, percentage of use, adherence and compliance and adverse effects of each contraceptive method. In order to reach to these aims, a retrospective study was conducted in Hawler City in Azadi Health Care Center over a period of 6 months from 22th November, 2010 to 15th May, 2011 during which data collection and subjects follow up for 3 months had been achieved. A conv
... Show MoreThe Rate theory of crack growth in PVC pipe has been studied for creep and fatigue crack propagation. Rate theory function parameters, (RTFP), were estimated theoretically from exponential function parameters, (EFP), to experimental data of crack velocity versus stress intensity factor ,(V-K) diagram, to creep crack propagation . Also (RTFP) were estimated theoretically from (EFP) to experimental data of (V-?K) diagram to fatigue crack propagation. Temperature effect with (RTFP) was discussed. Crack velocity function denoted with stress intensity factor and temperature degrees has been determined to fatigue and creep crack propagation theoretically and comparative results this function with experimental data of (V-K or ?K) diagram .
The aim of studying the role of environmental taxation is to reduce or mitigate the problem of environmental pollution and obtain a clean environment. And the importance of research lies in the fact that environmental taxation is one of the basic tools to achieve environmental balance. As it is considered one of the sustainable economic tools that focuses on the concept of environmental taxes and fees. Therefore, the incentives stimulated institutions to invest in clean energy and use environmentally friendly machines. Through it, the rules of the competition are updated in favor of organizations that respect the environment so that they can obtain a green competitive advantage. And that the mai
... Show MoreThe political movements of Islam are among the most prominent phenomena of the popular uprisings witnessed by the Arab world. However, this rise and the rise of some movements led to many problems on the political theses of Islam, especially those associated with the ideas of Islamic ideologues and their slogan Legitimacy and the authorities as the origin of the divine, and said the application to achieve the Islamic solution, and then became the state in theses of some Islamists a tool to apply the law and then the preservation of religion.
(disputed areas) before the establishment of the national government in Iraq in 1921, had to search for Arab tribes and clans in which the recipe group is available as a social organization coherent based on the foundations of several of them tribalism and her Land relates know Deira in those areas during the period that preceded the establishment of the national government in Iraq in 1921, and based on the inter girls primary sources and published mostly before the establishment of the national government in Iraq, the source of their information search and direct inquiry.
Research has proved that the tribes and clans of Arab exist in all districts described by (disputed), except (judicial Akre and Tilkaif) and varying degrees of time
Digital commercial advertising depends on artistic formations to achieve attraction and arousal of attention, which is one of the most important communication factors that the designer seeks to achieve and is considered a key key to recognizing the beauty of the topic and its functional value. Reframe formal vocabulary.
The research included the introduction and includes the research problem and the need for it, which focused on the following question: What is the aesthetic role of artistic formation in the design of commercial advertising?
The aim of the research was: To reveal the aesthetic role of artistic formation in commercial advertising.
It also included the importance of research and research boundaries, as well as def
The research is based on an important subject according to the researchers' estimations. It is the disclosure of the nature of the relationship between Watching to cultural programs in satellite channels and the book's vision of the intellectual, and the pursuit of purchasing and acquiring it It is a scientific addition to the scientific research media because it deals in the field of new about the nature of the relationship between satellite programs and writers, and it provides a scientific development on the importance of satellite channels in the promotion of the book and sales of intellectual elite. The study examined the audience of the recipients of literature for cultural programs, the nature of the public, characteristic
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