Background: Alterations in the microhardness and roughness are commonly used to analyze the possible negative effects of bleaching products on restorative materials. This in vitro study evaluated the effect of in-office bleaching (SDI pola office +) on the surface roughness and micro-hardness of four newly developed composite materials (Z350XT –nano-filled, Z250XT-nano-hybrid, Z250-mico-hybrid and Silorane-silorane based). Materials and methods: Eighty circular samples with A3 shading were prepared by using Teflon mold 2mm thickness and 10mm in diameter. 20 samples for each material, 10 samples for base line measurement (surface roughness by using portable profillometer, and micro-hardness by usingDigital Micro Vickers Hardness Tester), and 10 samples for after bleaching measurement. The appropriate bleaching procedure was performed on the top surface of test groups for 90 minutes total bleaching period. Then surface roughness and hardness were tested at the end of the duration. Statistical analysis was carried out using ANOVA, LSD and t-test. Results: There was a highly significant increase in surface roughness of all tested groups after bleaching. There is a highly significant increase in micro-hardness for Z250, there is decrease in Micro-hardness for siloraneand Z250xt and there is a non-significant increase in micro-hardness of Z350xt. Conclusion: bleaching has a negative effect on surface roughness of all the tested materials, as surface roughness increased after bleaching. Micro-hardness is a material dependent, there is different reaction to bleaching depending on the resin, load and size of the fillers used in the materials. Nano-filled composite is the material that has better performance than the other tested materials, as it is the material that has the least affection by bleaching.
Background : Bone infections is one of the most challenging orthopaedic complications, with considerable morbidity. There is significant impact on the life of the patients; socially, financially, physically, and mentally and it could be a limb-threatening complication. Osteomyelitis is a bone infection usually caused by bacteria, including mycobacteria, but mainly Staphylococcus aureus which is the most commonly responsible bacteria . Aim of study: To evaluate our management policy of chronic osteomylitis (C.O.M).
Methods : 32 patients presented with different types &forms of chronic osteomyelitis in many sites of long & flat bones such as tibia , femur, ,humerus ,iliac bones and knee joint , which are not response to previous
The issue of epistemology is one of the theological issues that were and still is a relentless pursuit of knowledge, knowing the true knowledge of certainty. Therefore, it formed a main focus because of its great importance expressing the deep desire of the human soul to explore the self and reality and answer all the questions that it may raise. Knowledge is the highest function. For man to exist.
Therefore, the establishment of epistemology was general in knowledge, a characteristic that was distinguished, as it is an ancient and renewed subject that is still being raised and raised, although there are many methods of treating it and sacred solutions to it. To finally prove its potentia
... Show MoreSince the beginning of Philosophical thinking, philosophers had interested in matters that related to psychology. Greek philosophy had sought different psychological cases such as knowledge, thought, sense, and cognition. Plato classified cognitive processes and distinguished between intelligence, emotions, and desires. As Aristotle believed that soul is the essence of human beings that characterize it from other creatures. Regarding the European philosophy, Descartes linked the optics field to psychology that comprises theories about visual perception. Then, john Watson who interested in behaviorism, he believes that the interpretation of behavior will be materialistic. However, the evolutionary view had great effect on psychology that
... Show MoreIn practical engineering problems, uncertainty exists not only in external excitations but also in structural parameters. This study investigates the influence of structural geometry, elastic modulus, mass density, and section dimension uncertainty on the stochastic earthquake response of portal frames subjected to random ground motions. The North-South component of the El Centro earthquake in 1940 in California is selected as the ground excitation. Using the power spectral density function, the two-dimensional finite element model of the portal frame’s base motion is modified to account for random ground motions. A probabilistic study of the portal frame structure using stochastic finite elements utilizing Monte Carlo simulation
... Show MoreTo obtain the approximate solution to Riccati matrix differential equations, a new variational iteration approach was proposed, which is suggested to improve the accuracy and increase the convergence rate of the approximate solutons to the exact solution. This technique was found to give very accurate results in a few number of iterations. In this paper, the modified approaches were derived to give modified solutions of proposed and used and the convergence analysis to the exact solution of the derived sequence of approximate solutions is also stated and proved. Two examples were also solved, which shows the reliability and applicability of the proposed approach.
Background: Because of the disturbance in the pituitary gland, growth hormone (GH) secretion will be increased and, as a result, insulin-like growth factor 1 (IGF-1) secretion will be increase as well, leading to a chronic and rare disease called acromegaly disease. One of the most serious complications of acromycaly is diabetes. Insulin resistance, which causes diabetes, occurs in the body because of increased growth hormone secretion Objective: The aim of this work is to estimate some biochemical parameters. These parameters were not studied extensively in the literature such as BALP and LOX and the possibility of using LOX as a new biomarker for acromyalgic patients with diabetic. Patients and Methods: The study was performed on (25) mal
... Show MoreFor structural concrete members that may expose to serious earthquake, overload or accident impact, the design of ductility must be given the same importance as the flexural strength. The aim of this investigation is to study the change in ductility of structural concrete flexural members during their exposure to limited cycles of repeated loading. Twenty full-scale beam specimens have been fabricated in to two identical groups; each group consisted of ten specimens. The first group was tested under monotonic static loading to failure and regarded as control beams, while the specimens of the second group were subjected to ten cycles of repeated loading with constant load interval, which ranged between 40% and 60% of ultimate load. S
... Show MoreFor structural concrete members that may expose to serious earthquake, overload or accident impact, the design of ductility must be given the same importance as the flexural strength. The aim of this investigation is to study the change in ductility of structural concrete flexural members during their exposure to limited cycles of repeated loading. Twenty full-scale beam specimens have been fabricated in to two identical groups; each group consisted of ten specimens. The first group was tested under monotonic static loading to failure and regarded as control beams, while the specimens of the second group were subjected to ten cycles of repeated loading with constant load interval, which ranged between 40% and 60% of ultimate load. S
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