Background: Separation and deboning of artificial teeth from denture bases present a major clinical and labortory problem which affect both the patient and the dentist. The optimal bond strength of artificial teeth with denture base reinforced with nanofillers and flexible denture bases and the effect of thermo cycling should be evaluated. This study was conducted to evaluate and compare the shear bond strength of artificial teeth (acrylic and porcelain) with denture bases reinforced by 5% Zirconium oxide nanofillers and flexible bases under the effect of different surface treatments and thermo cycling and comparing the results with conventional water bath cured denture bases. Material and methods: Two types of artificial teeth; acrylic and porcelain were used and prepared for this study. Five specimens of each tooth type were processed to each denture base materials after the application of different surface treatments; these teeth were bonded to heat polymerized, nano composite resin and flexible denture bases. Specimens were thermo cycled and tested for bond strength until fracture with an Instron universal testing machine. Data were analyzed with analysis of variance and student T-test. Photomicrographic examinations were used to identify adhesive and cohesive failures within debonded specimens. Results: The mean force required to fracture the specimens were obviously larger for nanocomposite specimens compared with the heat cured and flexible specimens. The most common failure was cohesive within the tooth or the denture base. With each base material, the artificial teeth which were treated with thinner exhibited highest shear bond strength. Thermocycling had deleterious effect on the flexible denture base specimens. In general, nanocomposite and heat cured groups failed cohesively within the artificial tooth. While the valplastic groups failed adhesively at the tooth denture base interface. Conclusions: Within the limitations of this study, the type of denture base materials and surface treatments of the tooth selected for use may influence the shear bond strength of the tooth to the base. Selection of more compatible combinations of base and artificial teeth may reduce the number of prosthesis fractures and resultant repairs. Key words: acrylic teeth, porcelain teeth, Nano composite denture base, thermo cycling, flexible denture, thinner,
The abdominal nerve cord of some species of Iraq Carabids has been studied to evaluate
the variation in the number of the abdominal ganglia among the species and to find out
relation of these variations with the classical taxonomy of the family Carabidae into tribes.
Research studies show that urban green spaces promote physical activity, the health of urban residents, and psychological well-being. Taking the community park in Duhok city as the research object, the spatial service area in terms of accessibility of to the Community Park under the mode of pedestrian transportation is analyzed by using the network analysis service area function of the geographic information system (GIS). The results show that under the walking mode in the research area, Parks are concentrated in the north and south of the city, but community parks are few in disadvantaged neighborhoods. In addition, there is a significant disparity between the number of community parks and the number of communities. Only 11 communities
... Show MoreJurisprudence of Imam women through Susan Book of blood money
Abstract
The goal of this research is to know the quality of working life and its impact on the level of the organizational sense of alienation among a sample of teaching Anbar University in the center of Baghdad. Find and seek to achieve a number of cognitive and practical goals.
Where the quality of work life constitutes one of the main sources to enable organizations of excellence in light of the volatile environment, as is one of alienation regulatory organizations avoid the phenomena that occur because of their negative effects on performance and thus achieve their goals. The most research problem in question the existence of the main deficiencies in the application of the concepts of organiz
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This study aims at recognizing Pesticides and how the process of pesticides biodegradation by microbiology took place, and the effect of environmental condition on this process. And how the research uncovered the efficiency of microbiology in the biodegradation process of pesticides, as the perfect temperature for the biodegradation process is 40 °C and humidity effect on pesticides efficiency, when high humidity reduces pesticide efficiency and the perfect acidity to increase bacteria efficiency is 7, for the incubation period, it was found during the previous studies that the best incubation period is 5-7 days, in this period the bacteria imprint on pesticides and increase biodegradation of it.
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he dairy industry is one of the industrial activities classified within the food industries in all phases of the dairy industry, which leads to an increase in the amount of wastewater discharged from this industry. The study was conducted in the Abu Ghraib dairy factory, classified as one of the central factories in Iraq, located in the west of Baghdad governorate, with a design capacity of 22,815 tons of dairy products. The characteristics of the liquid waste generated from the factory were determined for the following parameters biological oxygen demand (BOD5), Chemical oxygen demand (COD), total suspended solids (TSS), pH, nitrate, phosphate, chloride, and sulfate with an average value of (1079, 1945, 323, 9.2, 24, 2
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In "historical" fiction, characters that never really existed, give expression to the impact of historical events on the people who really did live through them. The result is not history, as an accurate record of actual events, but fiction in which an earlier age is rendered through the personal joys and sufferings of characters. This paper
aims at investigating the historical realities presented in Dickens’s A Tale of Two Cities.
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