Background: Adjustment of any premature occlusal contact of any zirconia restoration requires its polishing or glazing in order to restore the smoothness of the restoration. The objective of this in vitro study was to evaluate the effects of different polishing systems and glazing on the surface roughness of full-contour zirconia. Material and methods: Forty disks (diameter: 8 mm, thickness: 6.4 mm) were prepared from pre-sintered full-contoured zirconia block; they were colored and sintered in a high-temperature furnace at 1500˚C for 8 hours. The specimens were then leveled and finished using grinding and polishing machine and adjusted using diamond disk. The specimens were then randomly divided into four groups (n=10), group I involves samples that were polished using (karat diamond polishing set, Vita zahnfabrik, Germany), group II involves samples that were polished with (zirconia polishing kit, SMEdent, Shanghai, China), group III involves samples that were polished with (OptraFine® diamond polishing system, Ivoclar Vivadent, Germany), while group IV involves samples that were glazed using glazing medium (VITA Akzent Glaze AKZ 25, Vita zahnfabrik, Germany). Surface roughness values (Ra) (in µm) of all the specimens were recorded at each stage of surface treatment of zirconia disks (leveling and finishing, adjustment of the samples and polishing / glazing) using surface roughness tester. Statistical analysis was carried out using one-way ANOVA and LSD tests. Results: The results showed that the glazing group recorded the lowest surface roughness mean value, followed by (OptraFine® polishing system), then (zirconia polishing kit) and finally (karat polishing set) which showed the highest mean of surface roughness. For all groups, there was a statistically very high significant difference of (Ra) value before and after adjustment of the samples. Moreover, there was a statistically very high significant difference in (Ra) value when comparing the adjusted samples with the polished and glazed ones. Karat polishing set group showed a statistically highly significant difference with zirconia polishing kit group (P<0.01). Both, karat polishing set and zirconia polishing kit groups showed a statistically very highly significant difference (P<0.001) with (OptraFine® polishing system) and glazing groups. On the other hand, no statistically significant difference was found between glazing and (OptraFine® polishing system) groups (P>0.05). Conclusions: Adjusting full-contour zirconia with diamond bur or disk resulted in a significant increase in (Ra) that necessitates its polishing or glazing to restore the surface smoothness. Furthermore, both glazing and OptraFine® polishing system provided the best surface smoothness, so glazing can be substituted with chairside polishing using OptraFine® polishing system.
The present study aims to reveal the extent of the influence of the acquired organizational immune through its dimensions (organizational vaccination, organizational learning, organizational memory, and benchmarking) in the application of knowledge management strategies in its two dimensions (codification strategy, personalization strategy) as well as clarifying that influential relationship between the study variables Because of its importance in reducing resistance to change by responding to the requirements of the environment. A set of main and sub-hypotheses emerged from the study, which was formulated in view of the hypothesis scheme of the study, and i
... Show MoreArabic language , like any other living languages grow and evolve ; social phenomenon
it is subject to the law of life ; therefore resemble organism also touted as the most eloquent
language and the ability to meet the needs of people in every time and place.
The contemplation of the verses of the Koran reveals a lot of means of expression
leading to the grammatical meaning of the social.
I have tried in this research that investigated the social meanings through the phenomena
of deletion and delivery delays and capture semantic landing through the meanings that lead
to psychological persuasion to comply with the orders after the rights of the divine in which
social directives.
It remains the greatest mystery o
In recent decades, the identification of faces with and without masks from visual data, such as video and still images, has become a captivating research subject. This is primarily due to the global spread of the Corona pandemic, which has altered the appearance of the world and necessitated the use of masks as a vital measure for epidemic prevention. Intellectual development based on artificial intelligence and computers plays a decisive role in the issue of epidemic safety, as the topic of facial recognition and identifying individuals who wear masks or not was most prominent in the introduction and in-depth education. This research proposes the creation of an advanced system capable of accurately identifying faces, both with and
... Show MoreStaphylococcus haemolyticus is one of the most frequently isolated coagulase-negative staphylococci. The ability to form biofilm is considered as one of the most important virulence factors of coagulase negative staphylococci. There is only limited knowledge of the nature of S. haemolyticus biofilms. This study was aimed at evaluating the ability of S. haemolyticus strains to produce biofilm in the presence of copper oxide nanoparticles (CuONPs). The biological synthesis of nanoparticles is an environmentally friendly approach for large-scale production of nanoparticles. Copper oxide nanoparticles were produced in the current study from the S. haemolyticus viable cell filtrate. UV-visible (UV-Vis) spectroscopy, X-ray diffra
... Show Morethe researchers Sought to determine the impact of the customer contact (Within a client contact there are two times, first is the total time required to create a service and within it there is contact time while the second time is the time of client contact ؛ where means a time that records the physical presence of the customer during the process of service) on operations performance by concentrate attention on the cost (labor productivity) and quality (patient ratio to the doctor) and speed (cycle time) and flexibility (the flexibility range) , as well as ruling out variable of innovation because of impossibility to measure this variable in the Specialty Center for Dental in al-alwia due to the center is lacking of mechanisms t
... Show MoreThe vision and philosophy of the economic system in Iraq after 2003 were not clear-cut because of overlapping internal factors was the novelty of the political system and the lack of political and economic decision makers to understanding and conviction full need shaping a new administration for the Iraqi economy is able to succeed economic development programs, and external factors was determinedly organizations international application of shock reforming style and contrary to the social reality and the security which reflected negatively on the work and consistency Lisseeash financial balance between stability and growth and raise the level of consumer spending and the importance of research lies in the ability of fiscal policy to achie
... Show MoreIn this research thin films from SnO2 semiconductor have been prepared by using chemical pyrolysis spray method from solution SnCl2.2H2O at 0.125M concentration on glass at substrate temperature (723K ).Annealing was preformed for prepared thin film at (823K) temperature. The structural and sensing properties of SnO2 thin films for CO2 gas was studied before and after annealing ,as well as we studied the effect temperature annealing on grain size for prepared thin films .
In this study, the effects of different loading doses of cerium in the prepared NaY zeolite from Iraqi kaolin were investigated. Al-Duara refinery atmospheric residue fluid catalytic cracking was selected as palpation reaction for testing the catalytic activity of cerium loading NaY zeolite. The insertion of cerium in NaY zeolites has been synthesized by simple ion exchange methods. Three samples of modified zeolite Y have been obtained by replacing the sodium ions in the original sample with cerium and the weight percent added are 0.35, 0.64, and 1.06 respectively. The effects of cerium loading to zeolite Y in different weight percent on the cracking catalysts were studied by employing a laboratory fluidized
... Show MoreThe research aims to show the role or extent of the impact of financing in its various forms on the municipal performance before and after the financial deficit through relying on the analytical research methodology of the research community represented by the Directorate General of Municipalities and the Directorate of Maysan municipalities as a sample of research (13) municipal institutions for a period of (8) years, Considering the completion of the final accounts of these years, which provides the necessary data for the study, in addition to the variation in the quality and amounts of grants allocated to municipal institutions during these years, which gives a clearer and more comprehensive picture of the reality of allocatio
... Show MoreThe enrollment of students in the university represents a new stage in their life that differ from the previous educational stages that student has previously established. It should be noted that students with special needs at the University of Baghdad are not large numbers. It appears that these students have an excel role in their colleges most often, That is, the handicap was not a barrier to their scientific progress, but rather an incentive for them to excel. The most important conclusion reached by the researcher is that the University of Baghdad had no role in caring for people with special needs and caring for them financially, socially, psychologically, healthily and economically, they need to pay attention to them and take care
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