Background: This in vitro study measure and compare the effect of light curing tip distance on the depth of cure by measuring vickers microhardness value on two recently launched bulk fill resin based composites Tetric EvoCeram Bulk Fill and Surefil SDR Flow with 4 mm thickness in comparison to Filtek Z250 Universal Restorative with 2 mm thickness. In addition, measure and compare the bottom to top microhardness ratio with different light curing tip distances. Materials and Method: One hundred fifty composite specimens were obtained from two cylindrical plastic molds the first one for bulk fill composites (Tetric EvoCeram Bulk Fill and Surefil SDR Flow) with 4 mm diameter and 4 mm depth, the second one for Filtek Z250 Universal Restorative with 4 mm diameter and 2 mm depth. Each spcimen was light-cured using WOODPECKER LED CURING LIGHT for 20 sec. Polymerization was performed with the light tip positioned in direct contact, 2 mm, 4 mm, 6 mm and 8 mm distant from the top surface of the sample. After one day of storage in distilled water in a light proof container at 37ËšC, the hardness on the bottom and top surfaces of each specimen was tested using the Digital Micro Vickers Hardness Tester. Then the Data were analyzed statistically by ANOVA test, LSD test and t-test. Results: All experimental groups show top microhardness higher than bottom microhardness with high significant difference with all light tip distances. At 0 mm light tip distance all groups give the highest microhardness value. Filtek Z250 Universal Restorative shows accepted bottom to top microhardness ratio at all light tip distances. Surefil SDR Flow shows accepted bottom to top ratio only at 0, 2 and 4mm light tip distances while Tetric EvoCeram Bulk Fill shows the bottom to top microhardness ratio less than the accepted value with all light tip distances. Conclusion: From the results of this study we can conclude that the polymerization of bulk fill composite depends greatly on the distance from light curing tip, Tetric EvoCeram Bulk Fill composite not recommended to be used as bulk fill restoration in deep cavities and need further studies, while Surefil SDR Flow not recommended to be used in deep cavity when curing tip distance (6-8 mm), in addition we can conclude that the thickness of the increments is more important than light curing tip distance.
Motives: Baghdad is the capital city and an important political, administrative, social, cultural and economic centre of Iraq. Baghdad’s growth and development has been significantly influenced by efforts to accommodate various needs of its steadily growing population. Uncontrolled population and urban growth have exerted negative effects in numerous dimensions, including environmental sustainability because urban expansion occurred in green spaces within the city and the surrounding areas.Aim: The aim of this study was to examine the planning solutions in Baghdad’s green areas in the past and at present, and to identify the key changes in the city’s green areas, including changes in the ratio of green urban spaces to the tota
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THE EFFECT OF SPREACL of KNOWLEDGE ON ETHICS
The ration card system is a kind of support provided by the state to individuals through the provision of essential goods at subsidized prices during the period of war or crisis. For many years, the ration card was an essential source of food supplies to Iraqis, especially under the economic siege of the nineties, But after the events of 2003 and the passage of Iraq's political and economic changes required radical reforms in the ration card system according to the recipes of the International Monetary Fund. It was evident from the estimation of the demand function that the price did not have the greatest impact on this type of goods because the ration card items are subsidized by the government. There is also a
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Iraq suffers from lack of water resources supply because the headwaters of the rivers located outside its borders and the influence of upstream countries on the quantities of flowing water, in addition to the increase of pressure on available water as a result of population increase and not adopting the principle of rationalization where misuse and wastage and lack of strategic vision to treat and manage water use in accordance with the economic implications fall. This is reflected fallout on water security and subsequently on national and food security, while the issue of using water resources is development top priority in different countries in the world because of the importance of water effect on the security of indivi
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First: People’s need for advocacy:
Calling for a legal necessity for all people, regardless of their races, colours, tongues, and culture, to explain the truth, spread fear, bring benefits, ward off evil, regulate a person’s relationship with his Lord, and his relationship with creatures, so that he knows his money and what he owes.
All of creation is in dire need of the call to God’s religion with insight due to their inability to reach out to goodness, righteousness, guidance, and success on their own. Man is limited in thinking in this universe, limited in his resolve, unable to know what will improve his affairs in the two worlds. His need for religion is one of the necessities of his life, and one of the comple
... Show MoreViruses have not previously been reported to act as chemotactic/chemoattractive agents. Rather, viruses as extracellular entities are generally viewed as non-metabolically active spore-like agents that await further infection events upon collision with appropriate host cells. That a virus might actively contribute to its fate via chemotaxis and change the behavior of an organism independent of infection is unprecedented.
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The Assurance Services Are Represented By Expressing A Clear And Independent Opinion On All Financial And Non-Financial Information, As It Is Broader Than The Services Related To Auditing Financial Statements And Expressing Opinion (Certification) And Extends Them To A Wider Range, And It Is Possible To Distinguish Between Auditing And Certification Services And Confirming That Audit Services Relate To Expressing Opinion On Financial Statements And Certification Services Related To By Expressing An Opinion On A Wide Range Of Financial Information And More Broadly Than The Financial Statements And Assurance Services That Include Expressing An Opinion On Integrated Financial And Non-Financial Information And From This Standpoint Came The I
... Show MoreThe purpose of this research is to investigate the impact of corrosive environment (corrosive ferric chloride of 1, 2, 5, 6% wt. at room temperature), immersion period of (48, 72, 96, 120, 144 hours), and surface roughness on pitting corrosion characteristics and use the data to build an artificial neural network and test its ability to predict the depth and intensity of pitting corrosion in a variety of conditions. Pit density and depth were calculated using a pitting corrosion test on carbon steel (C-4130). Pitting corrosion experimental tests were used to develop artificial neural network (ANN) models for predicting pitting corrosion characteristics. It was found that artificial neural network models were shown to be
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