Background: The success and maintenance of indirect dental restorations is closely related to the marginal accuracy, which is affected by many factors like preparation design, using of different fabrication techniques, and the time of taking final impression and pouring it. The purpose of this in vitro study was to evaluate the effect of different pouring time of conventional impression on the vertical marginal gap of full contour zirconia crowns in comparison with digital impression technique. Materials and Methods: Forty sound recently extracted human permanent maxillary first premolar teeth of comparable size and shape were collected. Standardized preparation of all teeth samples were carried out to receive full contour zirconia crown restoration with deep chamfer finishing line all around the tooth with (1mm) depth, axial length (4mm) and convergence angle (6 degree). The specimens separated into two groups; Group A; eight specimens were scanned digitally by using Omnicam scanner; Group B; conventional impressions were taken for the remaining thirty two specimens and further subdivided to four groups according to the time of impression pouring; Group B1: PVS were poured after 30 minutes; Group B2: PVS were poured after 24 hours; Group B3: PVS were poured after 7 days; Group B4:PVS were poured after 14 days. Marginal discrepancy was measured at four points at each tooth surface. Sixteen points per tooth were measured using digital microscope at (180X) magnification. One-way ANOVA test and LSD test were carried out to see if there was any significant difference among the means of the conventional impression groups. Independent samples t-test was carried out to examine if there is any significant difference between digital and conventional impression technique. Results: group B2 had the least mean of marginal gap with statistically significant difference when compared to group B1 and statistically highly significant difference when compared to group B3 and B4. There was a statistically highly significant difference in the vertical marginal gap between digital impression technique and conventional impression. Conclusions: the pouring of conventional impression after 24 hours provides better marginal fit than other pouring time. The digital impression provides better marginal fit than conventional impression.
The hydrodynamics behavior of gas - solid fluidized beds is complex and it should be analyzed and understood due to its importance in the design and operating of the units. The effect of column inside diameter and static bed height on the minimum fluidization velocity, minimum bubbling velocity, fluidization index, minimum slugging velocity and slug index have been studied experimentally and theoretically for three cylindrical columns of 0.0762, 0.15 and 0.18 m inside diameters and 0.05, 0.07 and 0.09 m static bed heights .The experimental results showed that the minimum fluidization and bubbling velocities had a direct relation with column diameter and static bed height .The minimum slugging velocity had an
... Show MoreThe mediation system is based on settling the dispute amicably through the intervention of a third party by bringing views closer away from the judiciary, which is an amicable way to settle disputes, which disputants resort to voluntarily, but some Western legislation has begun to impose resorting to mediation to settle disputes compulsorily, to take advantage of its advantages, get rid of the disadvantages of resorting to the judiciary in some disputes, and relieve pressure on the courts.
This work is concerned with a two stages four beds adsorption chiller utilizing activated carbon-methanol adsorption pair that operates on six separated processes. The four beds that act as thermal compressors are powered by a low grade thermal energy in the form of hot water at a temperature range of 65 to 83 °C. As well as, the water pumps and control cycle consume insignificant electrical power. This adsorption chiller consists of three water cycles. The first water cycle is the driven hot water cycle. The second cycle is the cold water cycle to cool the carbon, which adsorbs the methanol. Finally, the chilled water cycle that is used to overcome the building load. The theoretical results showed that average cycle cooling power
... Show Morechronic obstructive pulmonary disease (COPD) is a common respiratory disease with episodes of exacerbation. Variable factors including infectious pathogen can predispose for this exacerbation. The aim of this study is to evaluate the role of intestinal protozoa in COPD exacerbation. A total of 56 patients with COPD were included in this study. Patients were categorized into two groups based on the frequency of exacerbation during the last 6 months: those with ≤1 exacerbation (32 patients) and those with ≥2 exacerbations (24 patients). Stool specimens from each patient were collected two times (one week interval) examined for intestinal parasite. In univariate analysis, rural residence and parasitic infection were more common among patie
... Show MoreThe rapid breakthrough achieved by technological progress in the field of designing and implementing women's fashion has resulted in the emergence of the need for quality control and control to improve the completed visual image of fashion as an aesthetic and functional product and not clothed in its abstract qualities.
The quality in women’s fashion and the importance of showing the design and conveying the design message to the recipient depends on the level of its implementation, starting from the selection of textile fibers and determining their appropriate characteristics for the functional purpose and design prepared by the designer and ending with the final operations of the costume. This calls for spreading awareness and c
The specialized Journalism plays an important role in our daily lives using all of its different ways, including news, caricature, commentary and dialogue. The specialized Journalism deserves vigilance and interest for it is caring about having a new media system. It is meant by “specialization”, first: identifying the areas of work in which the person concerned possesses great knowledge in the specialty resulting from a long experience, it also means being able to continuously develop required skills in that specialty. The specialization is not only a feature of the press, but also a feature of human development; thousands of years ago, the primitive society consisted of people from different specializations: fishermen, farmers, her
... Show MoreAlthough there are many wastewater treatment plants, we still suffer from many problems resulting from a lack of experience or technical operating problems. In this research, the service’s efficiency is evaluated according to the design laws required for small factories in the province of Najaf, which works with filtering technology through point filtration, the old project in the Al-Baraka plant, and the second works. Within the biological treatment mbbr + activated sludge, which is a biomass technology where samples were taken from both plants and annual values of the pollutant rate after treatment in the old Al-Baraka plant project COD 64 mg/L and the demand for biochemical oxyge
Controlling cost in construction projects is an essential issue. This study investigates the most critical problems that cause weakness in cost control in Iraqi construction projects. The quantitative technique was used by conducting a survey directed to professionals who work on construction projects. One hundred and sixty-four questionnaire forms were distributed to private sector companies, government companies, and government institutions, and the responses were subjected to the required statistical analysis. The results indicate that the most influential factors are the weakness in keeping up with the use of modern concepts, methods, and technologies, the delay in receiving the amounts due for work done from the owner, fluctuat
... Show More