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
Abstract
In the present study, composites were prepared by Hand lay-up molding. The composites constituents were epoxy resin as a matrix, 6% volume fractions of glass fibers (G.F) as reinforcement and 3%, 6% volume fractions of preparation natural material (Rice Husk Ash, Carrot Powder, and Sawdust) as filler. Studied the erosion wear behavior and coating by natural wastes (Rice Husk Ash) with epoxy resin after erosion. The results showed the non – reinforced epoxy have lower resistance erosion than natural based material composites and the specimen (Epoxy+6%glass fiber+6%RHA) has higher resistance erosion than composites reinforced with carrot powder and sawdust at 30cm , angle 60
... Show MoreThis study aimed to measure the accounting conservatism and the lemited factors which affected on it in the annual financial reports of insurance companies which listed on the Amman Stock Exchange during the period from 2005 to 2016, these factors were represented by firm age, firm debt and firm size.
Using the market value model (MV) To book value ( BV) Beaver and Ryan (2000) The level of the accounting conservatism was measured. The study found that the insurance companies which are listed on the ASE exercise the accounting conservatism when they were preparing financial reports. And when conducting a process of the test of the affected of the factors (The age of the
... Show MoreThe child realize that the meals time provide golden opportunities to get the attention the child needs. However, many difficulties that may appear about eating food can be avoided, if the family used the right way in dealing with this problem. The study aims, in this case, at searching for the reasons that lies behind the child's obstinacy in eating his food and the attempt to study some variables that is related to the research topic.
The results are summed up as follows:
- The number of the sample children is 3 of both sexes between the ages of 3 to 6 years
Braces in straight bridge systems improve the lateral-torsional buckling resistance of the girders by reducing the unbraced length, while in horizontally curved and skew bridges, the braces are primary structural elements for controlling deformations by engaging adjacent girders to act as a system to resist the potentially large forces and torques caused by the curved or skewed geometry of the bridge. The cross-frames are usually designed as torsional braces, which increase the overall strength and stiffness of the individual girders by creating a girder system that translates and rotates as a unit along the bracing lines. However, when they transmit the truck’s live load forces, they can produce fatigue cracks at their connection
... Show MoreThis study unveils the ideologies of women empowerment encoded in the Mona Lisa Smile movie (2003). It reveals how the stereotypical image of women born only to be wives and do the duties of upbringing and housework is challenged. Katherine Ann Watson (Julia Roberts), the main character in the movie, wants to make a difference in the next generation of women. She rejects the imposed traditional ideologies. Linguistically, she opposes conventional thinking and seeks to persuade her students that life is about more than getting married. The primary focus of this study is to examine and clarify how the characters’ linguistic choices convey their ideologies concerning the notion of women empowerment. To do this, the researchers apply
... Show MoreCorrosion experiments were carried out to investigate the effect of several operating parameters on the corrosion rate and corrosion potential of carbon steel in turbulent flow conditions in the absence and presence of sodium benzoate inhibitor using electrochemical polarization technique. These parameters were rotational velocity (0 - 1.57 m/s), temperature (30oC – 50oC), and time. The effect of these parameters on the corrosion rate and inhibition efficiency were investigated and discussed. It was found that the corrosion rate represented by limiting current increases considerably with increasing velocity and temperature and that it decreased with time due to the formation of corrosion product layer. The corrosion potential shifted t
... Show MoreWorld War II has brought suffering for all people; it has led people to have a nostalgic feeling. The war has many faces all of them are ugly, like death, separation, loneliness, violence, crime, betrayal, and disconnection and many other meanings. Michael Ondaatje in his novel The English Patient (1992) portrays a picture of the effect of World War II on four different characters; Hana a Canadian nurse, The English patient who is Hungarian, Caravaggio a Canadian-Italitan thief, and Kip an Indian sapper. They live together in one house, share their secrets and memories about World War II. Ondaatje brings them together to reveal their secrets and to heal their wounds of the war experience.
World War II has brought suffering for all people; it has led people to have a nostalgic feeling. The war has many faces all of them are ugly, like death, separation, loneliness, violence, crime, betrayal, and disconnection and many other meanings. Michael Ondaatje in his novel The English Patient (1992) portrays a picture of the effect of World War II on four different characters; Hana a Canadian nurse, The English patient who is Hungarian, Caravaggio a Canadian-Italitan thief, and Kip an Indian sapper. They live together in one house, share their secrets and memories about World War II. Ondaatje brings them together to reveal their secrets and to heal their wounds of the war experience.
The UN organization is considered one of the most important organizations at the international level. It has accomplished multiple tasks and roles of many different issues and events that hit the developing and advanced world countries. It has performed a series of procedures and laws that have had an impact on ending the wars and conflicts that plagued some countries and continued for a period of time in the past. Moreover, it has improved the level of the international relations between a number of countries due to the problems and incidents took place between them. It has relied on finding solutions and treatments for humanitarian problems such as the preservation of the environment, preventing the spread of epidemics and diseases Thi
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