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,
In our time, not too long ago, the universities of the world have been fast to take care of the study of an innovative type of technical and human studies, called the science of "comparative literature". Comparative research studies have grown and flourished rapidly in response to the demands of both mental and artistic life. This shows the increasing awareness at both the modern national and the international levels in order to develop through connecting with the international intellectual, nental and artistic currents to nurture ethics and originality. Comparative studies show that the beginning of the comparative literature goes back to the time when the Latin literature was connected to the Greek literature and th
... Show MoreConcentrated research topic in the study of key variables in the work of the inspectors general offices , which are in the application of quality management standards audit work and reduce the incidence of corruption. It highlights the importance of current research in being a serious attempt aimed at highlighting the role of the importance of standards of quality management audit work , because they represent a router and leader of the accountant or ( Sergeant ) in the performance of his work and the extent of compliance with these standards , as well as highlight the role of quality audit in reducing the incidence of corruption , of during the professional performance of Higher auditors and determine the responsibilities entrus
... Show MoreThe research aims to answer the questions that revolve in the mind of mankind about how to create creation, how it existed prior to creation, who created existence, and the characteristics of that presence. The researcher also wanted to show that the culture of Imam Ali (peace be upon him) In the book of Adam, peace be upon him, God has punished Adam (peace be upon him) for not having sinned. Because his wife is the one who fed him the fruit of the tree, and this is contrary to what was stated in the sermon of Imam (peace be upon him) who Z Adam (peace be upon him) is the one who trusted Satan and Gwighth.
We note that the approach of the rhetoric has pointed to the creation of angels and did not refer to
... Show MoreObjective: the aim of this study is to determine the level of students' knowledge about the environmental health.
Methodology: The cross-sectional study was conducted at the College of Health and Medical Technology in Baghdad
city during the period from 1st march till 1st of July 2012. Data was collected by self-recording of a previously designed
questionnaire to obtain socio-demographic information such as (age, gender, department, year of grade).
Results: The highest rate of students were in the 2nd year followed by the 3rd year, highest rate of students had low
level of knowledge followed by intermediate level of knowledge, while lowest rate of students on had high level of
knowledge .Females had higher level of know
Although many technological improvements are occurring in power production worldwide, power plants in third world countries are still using old technologies that are causing thermal pollution to the water bodies. Power facilities that dump hot water into water bodies are damaging aquatic life. In the study, the impact of the Al Dora thermal power plant on a nearby stretch of Tigris River in Baghdad city was assessed by measuring the temperature of the disposed of hot water in various cross-sections of the selected stretch of Tigris River, including measuring the thermal mixing length. The measurements were conducted in winter, spring, and summer. For field measurements, it was found that the impact of recovery distances
... Show MoreSome aspects of population dynamics of both corbicula species inhabiting intertidal zone of
shatt al-Arab are described. These informations are explained in accordance with the possible
occurrence of competition between the two related species.
The research aims to identify the administrative skills and their role in institutional performance, and used the descriptive approach in a survey style and correlational relations to suit the nature of the problem to be studied.The research community was identified with the directors of sports activity in the Iraqi universities in a deliberate manner, and their number is (134) directors, where two scales (administrative skills and institutional performance) were used and the two scales were distributed to the above-mentioned sample in order to obtain answers that meet the required and representative sample of the community on the day 3/12/2021. The answers to all the statements were completed and after processing the results statistically
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The basic orientation of the research is an attempting to apply the cost determining method according in the contract sector projects for Al- Iraq ceneral company, that this subject has a big value according to its modernity and its influence on the future and the eaning of the company.
The research aims to find out the effect of the method for determining cost based on the activity in determining the cost of the construction sector projects.The research was conducted in Iraq General Company for the implementation of irrigation projects. Bani search on three assumptions, the first is (that the application of the method for determining the cost on the basis of
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