Abstract: Objectives: To investigate the effect of temperature elevation on the bonding strength of resin cement to the zirconia ceramic using fractional CO2 laser. Background: Fractional CO2 laser is an effective surface treatment of zirconia ceramic, as it increases the bonding strength of zirconia to resin cement. Methods: Thirty sintered zirconia discs (10 mm diameter, 2 mm thickness) were prepared and divided to three groups (N=10) and five diffident pulse durations were used in each group (0.1, 0.5, 1, 5 and 10 ms). Group A was treated with 10 W power setting, group B with 20 W and group C with 30 W. During laser irradiation, temperature elevation measurement was recorded for each specimen. Luting cement was bonded to the treated zirconia surfaces and cured for 30 seconds. Shear bond strength was evaluated by a testing machine (universal) with bond failure mode determination. Results: The lowest temperature elevation measurement of the irradiated specimen which gave maximum shear bond strength was about 1.6±0.3 Ċ higher than ambient room temperature (27±0.2 ºC). Apparent micromechanical irregularities were seen in the treated samples and cracks formation with increased pulse duration and power setting were also observed. Conclusions: The temperature elevation is a vital factor in the surface roughness of zirconia ceramic with fractional CO2 laser irradiation and the lowest temperature elevation at best shear bond strength of zirconia ceramic to the resin cement is satisfied with the shorter pulse duration of 0.1 millisecond.
The research aims at:
- Identifying the problems facing kindergarten teachers.
- Identifying the nature of the problems facing kindergarten teachers.
To achieve the aim of the research, the researcher prepared a questionnaire to identify the problems that face the teachers of kindergartens. The questionnaire was subjected to the consultation of a group of specialized expertise in the educational and psychological sciences to certify the propriety of the items of the questionnaire and it gained a rate of (80%), and the stability of the scale gained (0.91) and it stands for a correlation parameter with a statistical significance and it was calculated by using Person’s R Corre
... Show MoreThe bony pelvis has a major role in weight transmission to the lower limbs. The complexities of its geometric form, material properties, and loading conditions render it an open subject to biomechanical analysis.
The present study deals with area measurement, and three-dimensional finite element analysis of the hip bone to investigate magnitudes, load direction, and stress distribution under physiological loading conditions.
The surface areas of the auricular surface, lunate surface, and symphysis pubis were measured in (35) adult hip bones. A solid model was translated into ANSYS parametric design language to be analyzed by finite element analysis method under different loading conditions.
The surface
... Show MoreThe Educational Ideology of John Dewey
This paper exclusively deals with medical encounters. . Structurally and thematically, it manifests itself in five parts. The First part deals with medical encounters as well as essential speech activities which cover (a) frames (certain types of talk) (b) the patient’s account and the patient’s story or more precisely the patient telling his story and (c) the act of questioning the patient. The Second part revolves round genre and register. The former, in most cases, suggests that the format of medical encounters is conversational. With register; we have a converse reality that restrictively tries to narrow things and give them a certain flavor. The Third part realizes the technicalities of medical encounters (a) the setting of an inte
... Show Morethe chormanal some complement of barbus grypius is found to be 98 consisting of 22 melaccntricsomes it is probably a tetraploid species and more advanced than other speice haveing the same ehromosome under and belonging yo the genus barbus
The current study aims to find out:
- The ingratiating behavior of university students.
- The differences of statistical significance in The ingratiating behavior among university students according to the variables of sex and specialization
The current study is determined by University of Baghdad students of both genders (males and females) and for both majors (scientific and humanities) for the academic year (2019-2020).
In order to achieve the researcher's objectives:Ingratiating behavior scale has been constructed. It consists in its final form of (32) items divided into four behaviors. The researcher has extracted scale validity and reliability.
The researcher based the two scales
... Show MoreEncouraging children towards the cognitive motivation through the discovery and knowledge of the environment around them is essential. Thus, during the two researchers’ supervision of the practical lessons that involved the female students’ application of their experience in the Applied Kindergarten Laboratory, it has been noticed that there was a difference in the cognitive motivation of kindergarten children. In order to reinforce the research problem, the two researchers sent an open questionnaire to a sample of randomly selected kindergarten teachers from Al-Karkh and Al-Rasafa sides. The responses collected accentuated the researchers’ sense of the existing problem. To achieve the aim of the study represented by examining the
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Our country faced lots of crises specially Wars and still living under the traumatic events. This would result in psychological disorder specially the Acute Stress Disorder (ASD). That’s if not treated, it will turn to be over Post Traumatic Stress Disorder(PTSD). Also not mentioning the shortage of recourses speaks about war and crises. That treat with its inflections psychologically and sociologically theses cases if happened.
The importance of this study arise through it is objective to introduce a program for EMDR which give benefit for treat in health, social, educational institutes.
Aims:
The objective of this Study is the identification of a Test the effectiveness of Eye Movement Desensi
... Show MoreThe importance of research stems from the prominent role of leaders in the political, administrative, economic and societal spheres in general, which requires highlighting this angle. Research Hypothesis Modern policies work with mechanisms that limit the clear role of governors and transform the ruler into an executive man. It can be assumed that the type of public policy of the state is the only criterion that transfers the ruler from a ruler to an executive.