Background: The marginal adaptation has a key role in the success and longevity of the fixed dental restoration, which is affected by the impression and the fabrication techniques .The objective of this in vitro study was to evaluate and compare the marginal fitness of lithium disilicate crowns using two different digital impression techniques (direct and indirect techniques) and two different fabrication techniques (CAD/CAM and Press techniques). Materials and Methods: Thirty two sound upper first premolar teeth of comparable size extracted for orthodontic reason were selected in this study .Standardized preparation of all teeth samples were carried out with modified dental surveyor to receive all ceramic crown restoration with 1 mm deep chamfer finishing line, 4 mm axial length and 6 degree convergence angle. Half of the teeth were duplicated and poured in type IV dental stone to have sixteen dies and then these dies and the remaining teeth divided in to two groups according to the type of digital impression techniques (n=16) as follow: Group A: Indirect digital impression technique scanned by inEos X5 camera; Group B: Direct digital impression technique scanned by CEREC AC Omnicam camera. Each group was subdivided according to the technique of fabrication into two subgroups (n=8): Press technique using IPS e-max press (A1, B1); CAD/CAM technique using IPS e-max CAD (A2, B2).Marginal gaps were evaluated on the prepared teeth at four defined points on each aspect using digital microscope at a magnification of (280X). One way ANOVA and LSD tests were used to identify and localize the source of difference among the groups. Results: The results showed that indirect digital impression with IPS e-max CAD/CAM group A2 revealed the poorest marginal integrity with (55.93 μm ± 3.300). Group B2 and group A1 were next in line with(44.49 μm ± 6.840 and 37.74 μm± 5.433) respectively, while in the first group of restorations, the result of 29.9 μm ± 5.534 obtained with direct digital impression with pressable ceramic was clearly better. Conclusions: All the tested digital impression techniques showed clinically acceptable accuracy and intraoral scanning with pressable ceramic significantly enhanced the marginal fit
The characters of facades' form of the Iraqi building after 2003 have been changed, it has been described by many names. The problem of the research is that what are the features of the characters of the form in the façades of the buildings in Baghdad city after 2003? Are the façade of the individual houses or the commercial buildings is the heaviest in the visual weight? The research aims to answer those questions by choosing the vernacular architecture as a measurement tool. It is the informal image of the architecture, which is built by people informally and spontaneously, without official control and legislation to be organized. This is smellier to what has happened in Baghdad, after 2003 according to previous study submitted
... Show MoreThe current study, which extended from February 2020 to June 2021 at the University of Thi- Qar\ College of Education for Pure Sciences, aimed to follow the changes in external morphological features at different Embryonic Developmental stages in pregnant mice treated with different doses of Rapamycin (Rapa). Use In this study, 32 pregnant mice were divided randomly into four groups, each of which had eight pregnant mice. Each group received different dose of Rapa via intraperitoneally injection at different gestation days until the end of the specified periods, whereas the control group received a DMSO. Mice were administered under the same circumstances and dosages were determined based on body weight, as specified in pharmaceutical const
... Show MoreObjective(s): The world of dentistry is constantly evolving, and with the advent of 3D printing technology, the possibilities are endless. However, little is known about the effects of adding ZrO2 NPs to the denture base resin of 3D additive manufacturing technique.Aim of this study is to evaluate the behavior of resin which is used to 3D printing of denture base with the addition of ZrO2 NPs on denture adaptation property and diametral compression strength.Methods: 60 samples were printed, 30 disks for diametral compressive test and 30 denture base for denture adaptation test. Three groups per test (n=10). The control group for each test included unreinforced 3Dprinted denture base resin, and the other groups were reinforced with (2&
... Show MoreIn this work, the geomagnetic storms that occurred during solar cycles 23 and 24 were classified based on the value of the Disturbance Storm Time index (Dst), which was considered an indicator of the strength of geomagnetic conditions. The special criterion of Dst >-50 nT was adopted in the classification process of the geomagnetic storms based on the minimum daily value of the Dst-index. The number of geomagnetic storms that occurred during the study period was counted according to the adopted criteria, including moderate storms with (Dst >-50 nT), strong storms with (Dst >-100 nT), severe storms with (Dst >-200 nT), and great storms with (Dst >-350 nT). The statistica
Abstract
Experimental work from Magnetic Abrasive Finishing (MAF) tests was carried out design parameters (amplitude, and number of cycle which are formed the shape of electromagnetic pole), and technological parameters (current, cutting speed, working gap, and finishing time) all have an influence on the mechanical properties of the surface layer in MAF process. This research has made to study the effect of design and technological parameters on the surface roughness (Ra), micro hardness (Hv) and material removal (MR) in working zone. A set of experimental tests has been planned using response surface methodology according to Taguchi matrix (36) with three levels and six factors
... Show MoreAt a time when the general rules in the different legal systems require the presence of two parties to the contract, one of which is issued the first expression of the will and is called the offer, and the other is issued from the other and is called the acceptance. A special type of contracts emerged in the beginning of the last century called the “unilateral contracts”. The side sparked a major jurisprudential dispute, as well as the issuance of several contradictory judicial rulings on it. Hence, this research came to highlight this special type of contract. Key words: the definition of a unilateral contract, its distinction from other legal situations, and its effects.
BACKGROUND: Genetic skeletal abnormalities are a heterogeneous group of genetic disorders frequently presenting with disproportionate short stature. AIM OF THE STUDY: To give an idea about the frequency of genetic skeletal abnormalities, and to find out whether these disorders are really increasing in the last 16 years or not. METHODS: During the period extending from (Jan, 1st 2003-April, 1st 2007), all cases of genetic skeletal disorders referred to the Genetic Counseling Clinic, Medical City – Baghdad who were born after 1991 were included in this study as the post-war group; the pre-war group, included all cases of skeletal disorders referred prior to 1991 (Jan., 1st 1987-Jan., 1st 1990). The demographic parameters, family history of
... Show MoreThe nuclear structure of 38Ar, 59Co, 124Sn, 146Nd, 153Eu and 203Tl target nuclei used in technology for nuclear batteries have been investigation, in order that, these nuclei are very interesting for radioisotope thermo-electric generator (RTG) space studies and for betavoltaic battery microelectronic systems. The single particle radial density distribution, the corresponding root mean square radii (rms), neutron skin thicknesses and binding energies have been investigated within the framework of Hartree-Fock Approximation with Skyrme interaction. The bremsstrahlung spectrums produced by absorption of beta particles in betavoltaic process and backscattered p
... Show MoreIn this research, damping properties for composite materials were evaluated using logarithmic decrement method to study the effect of reinforcements on the damping ratio of the epoxy matrix. Three stages of composites were prepared in this research. The first stage included preparing binary blends of epoxy (EP) and different weight percentages of polysulfide rubber (PSR) (0%, 2.5%, 5%, 7.5% and 10%). It was found that the weight percentage 5% of polysulfide was the best percentage, which gives the best mechanical properties for the blend matrix. The advantage of this blend matrix is that; it mediates between the brittle properties of epoxy and the flexible properties of a blend matrix with the highest percentage of PSR. The second stage
... Show MoreThis study was conducted to evaluate the efficacy of different techniques for extraction and purification of Tomato yellow leaf curl virus (TYLCV). An isolate of the virus free of possible contamination with other viruses infecting the same host and transmitted by the same vector Bemisia tabaci Genn. was obtained. This was realized by indicator plants and incubation period in the vector. Results obtained revealed that the virus infect Nicotiana glutinosa without visible symptoms, while Nicotiana tabaccum var. White Burley was not susceptible to the virus. The incubation period of the virus in the vector was found to be 21 hrs. These results indicate that the virus is TYLCV. Results showed that Butanol was more effective in clarification the
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