Background: Crown preparation of vital teeth involve the removal of a sound tooth structure, and when enamel removed this lead to exposed dentin with an increase in the number of open dentinal tubules also the diameter of dentinal tubules will increase, furthermore lead to increase movement of fluids inside the tubules all that causes post preparation sensitivity. The aim of this study is to evaluate the effect of desensitizing by Er:Cr:YSGG laser on shear bond strength of prepared tooth and resin cement. Materials and methods: Thirty sound maxillary premolars, grouped into three groups(n=10). Group A is the control group, group B irradiated by Er:Cr:YSGG laser with (0.25 W, 20 Hz, 10%water and air), group C irradiated by Er:Cr:YSGG laser with (0.5 W, 20 Hz, 10% water and air). Results: SEM examination showed complete occlusion of opened dentinal tubules after laser irradiation of both groups that irradiated with laser. Statistical analysis showed significant increase in surface roughness in group B and C. SBS was significantly increase in group B with no significant increase in group C. Conclusion: Er:Cr:YSGG laser can occlude open dentinal tubules without and adverse effect on the retention of the restoration, on the contrary it increase bonding strength. And this increasing was significant in group B with (0.25W, 20 Hz, 10 % water and air). suggestion: so the parameters used in group B (0.25 W, 20Hz, 10 % water and air) is recommended for desensitizing prepared tooth and induce enhancement to the bonding strength of resin to tooth surface.
Gypseous soil is a collapsible soil, which causes large deformations in buildings that are constructed on it. Various methods have been used to minimise this effect, such as replacing the gypseous soil or using soil stabilisation (grouting or soil improvement). This study was carried out on four types of gypseous soils that have different properties and various gypsum contents. The testing was carried out on remoulded samples to evaluate the compressibility of gypseous soil under different conditions. The samples were grouted with acrylate liquid. The relationships between the injection pressure and the radius of flow, between time of injection and radius of flow, and between time and quantity of acrylate liquid are investigated on
... Show MoreThis paper discusses the Sums of Squares of “m” consecutive Woodall Numbers. These discussions are made from the definition of Woodall numbers. Also learn the comparability of Woodall numbers and other special numbers. An attempt to communicate the formula for the sums of squares of ‘m’ Woodall numbers and its matrix form are discussed. Further, this study expresses some more correlations between Woodall numbers and other special numbers.
Seven species of semi venomous Opisthoglypha snakes (Reptilia, Ophidia) of Iraq are listed with important characteristics in morphology due to geographical and individual variation of species, as well, the confusion in the scales count of Telescopus tessellatus martini (Schmidt, 1939) of Iraq are discussed.
Background: The microorganisms can impend the life of health care professional and particularly the dental practitioners. They can be transmitted by different ways like airborne and droplet transmission. The current study was carried out to identify whether the arch wires that received from the manufactures are free from microbial contamination and to determine the bacterial species attached to the arch wires. Materials and Methods: This study involved eighty samples, consisted of two types of arch wires (nitinol and stainless-steel) from four companies (3M, G&H, Jiscop, OrthoTechnology). These wires inserted in a plane tube that contains 10 -ml of (Tris [tris(hydroxymethyl)aminomethane] and EDTA (ethylenediaminetetraacetic acid) tri
... Show MoreThe practice of art is an inevitable result imposed by the circumstances surrounding the human being, as he needs some knowledge associated with raw materials, tools and methods to develop skills in the formation of elements of the work of art in new ways that give a decent artistic appearance to the work of art. Through the exploratory study carried out by the researcher, which included asking the following question to the third grade students, Department of Art Education:
What types of materials are used in handicrafts and from which sources are they obtained? Through the answers, the problem of research was founded as follows:
-Are the products of students of the Department of Art Education in the handicraft material d
... Show MoreThe aim of this research is to identify the level of mental mindfulness among female students of the College of Education at Umm Al-Qura University, as well as to identify the statistically significant differences in the level of mental mindfulness according to academic level, specialization, and academic achievement. A mental mindfulness scale was designed to cover five dimensions. The study employed the analytic descriptive approach applied to a random sample of (217) female students from various academic specializations. The findings indicated that the level of mental mindfulness was average among female students. Statistically significant differences were attributable to the academic level, academic specializations, and academic achi
... Show MoreThis research aims to measure the discrepancy between the accounting income which is prepared according to generally accepted accounting principles and the tax income that is being prepared according to the rules and tax laws, and find out the most important differences that arise between incomes.The research found the most important to the following conclusions:1.Faces determining the tax base for companies subject to income challenges related to the weakness of the efficiency and the possibility of technical angel tax and its ability to examine the financial statements submitted to the tax administration tax.2.That the tax system in Iraq does not comply with accepted accounting principles generally accepted.The research recommends the
... Show MoreThe study aimed at identifying the level of administrative work quality of private Schools principals at Southern Governorates of Palestine from the teachers' point of view in their schools. To achieve the objectives of this research, a questionnaire was prepared by the researcher consisted of (28) items. It was applied to a sample of (350) teachers. The researcher adopted the descriptive-analytical approach. The results of the study showed that the degree to which principals of private schools in the southern governorates of Palestine practice Administrative Work Quality from the viewpoint of their teachers was very high, with relative weight (85.00%). The results also showed that there are statistically significant differences at the l
... Show MoreThe current research aims to find out ( the effectiveness of the structural model of learning in the acquisition of geographical concepts at the first grade average students ) , and achieving the goals of research has been formulating the null hypothesis of the following :
" There is no difference statistically significant when Mistoi (0.5 ) between the mean scores of the collection of students in the experimental group that is studying the general geographical principles " Bonmozj constructivist learning " and the mean scores of the control group , which is considering the same article ," the traditional way " to acquire concepts.
The researcher adopted th
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