Background: The bonded orthodontic retainer constructed from multistrand wire and composite is an efficient esthetic retainer, which can be maintained long-term. Clinical failures of bonded orthodontic retainers, most commonly at the wire/composite interface, have been reported. This in vitro investigation aimed to evaluate the tensile forces of selected multistrand wires and composite materials that are available for use in the construction of bonded fixed retainers. Materials and Methods: The study sample includes 120 wires with three types of retainer wires (3 braided strands\ Orthotechnology, 8 braided strands\ G&H Orthodontics, 6 coaxial strands\ Orthoclassic wires), two types of adhesive (flowable\ Orthotechnology, non flowable\ G&H Orthodontics composites) and two thickness of the adhesive (1mm, 2mm). The samples were prepared for each composite in which a wire was embedded; then the composite was light cured for 40 seconds and the specimens were stored in artificial saliva at 37°C in the incubator for 24 hours. The ends of the wire were drawn up and tensile force was applied through Tinius-Olsen universal testing machine until the resin failed and the results were recorded in Newton (N). Results: Statistical analysis showed that there was a highly significant difference (P ≤ 0.01) among the mean values of tensile forces of the three types of retainer wires in each thickness of composite with exception of a non significant difference (P > 0.05) between (3 braided) and (8 braided) and a non significant difference (P > 0.05) between (3 braided) and (6 coaxial) in both thickness of composite, a highly significant difference (P ≤ 0.01) between the two thickness of both composite types in each wire type and a highly significant difference (P ≤ 0.01) between the two types of composite in each wire type of both thickness of composite. Conclusion: The result of this study revealed that the 8 braided strands retainer wire shows the highest values of tensile force among the tested retainer wires, the non flowable composite demonstrates a higher tensile force than the flowable composite and increasing the thickness of composite overlying the wire increased the force required to detach the wire from the composite.
In the present study, a novel ligand (L) made of 2-hydroxynaphthaldehyde and 3-hydrazone-1,3-dihydro-indole-2-one(3-[(3-hydroxynaphthalen-2-yl-ethylidene)-hydrazono]-1,3-dihydro-indol-2-one). The ligand was characterized by FTIR, UV-vis, mass, 1H-NMR, 13C-NMR, and CHN elemental analysis. New complexes of this ligand were created by treating methanol and a drop of DMF solution of the produced ligand with the hydrated metal salts of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) in a molar ratio of 2:1 (L:M). As a result, complexes have been emerged and identified FTIR, UV-vis, C.H.N., chloride-containing, molar conductance, magnetic susceptibility, and atomic absorption. The characterization result for each complex indicated complexes wi
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The studies on unbonded post-tensioned concrete members strengthened with Carbon Fiber Reinforced Polymers (CFRPs) are limited and the effect of strengthening on the strain of unbonded pre-stressed steel is not well characterized. Estimating the flexural capacity of unbound post-tensioned members using the design methodology specified in the design guidelines for FRP strengthening techniques of bonded post-tensioned members does not provide a reliable evaluation. This study investigates the behavior of unbonded post-tensioned concrete members with partial strand damage (14.3% and 28.6% damage) and strengthened with CFRP laminates using a near-surface mounted technique with and without U-wrap anchorages. The experimental results show
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Objectives: To assess levels of premenstrual psychological disorders of the students in Bab Al-Mua’dham Complex and to find out the relationship between the levels of premenstrual psychological and physical disorders and some demographic characteristics of the students. Methodology: A descriptive study was accomplished throughout the period from the 1st of October, 2015 to the 8th of July, 2016 to assess the psychological and physical problems. A purposive sample of 313 students distributed among different colleges of Bab Al-Mua’dam complex distributed as following: 82 students are from college of Arts; 79
Time is very important in educational institutions. It is also one of our contemporary problem ‚as time is a clear – cut and limited factor‚ it demands that administrators should monitor it by administering and monitoring the principles of time.
Hence‚ the researcher attempts to identify the skills of administrating time and the reasons that cause the waste of time of the Heads of Departments at university of Baghdad.
Significance of the research:
Time is very important to all educational administrators and one of them is the institutions of Higher education. One of the
... Show MoreCancer stay to be one of the leading causes of death throughout the world due to a limited success to use treatments. The new synthesized metal complexes with formula: [Ni L2 (H2O)2]. 2.5 E t OH and [Cd L2]. ½ H2O Where L = Bis [ 5 – ( P – nitrophenyl ) - 4 – phenyl 1 , 2 , 4 – trazol – 3 – dithiocarbamato hydrazide ] and the aqueous extract of Teucrium polium L.(TP) plant (Ja,adahin Arabic) were examined against growth cells of hepatocellular Carcinoma cell Line ( HeP2 ). The cytotoxicity assay of cancer cell line was used for determination of inhibition rate with three concentrations; (62.5, 105 and 250 µg /200µl). The aqueous extract of TP plant induced death of cancer cells by significant elevation of the inhib
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AO Dr. Ali Jihad, Journal of Physical Education, 2021
There are many techniques that can be used to estimate the spray quality traits such as the spray coverage, droplet density, droplet count, and droplet diameter. One of the most common techniques is to use water sensitive papers (WSP) as a spray collector on field conditions and analyzing them using several software. However, possible merger of some droplets could occur after they deposit on WSP, and this could affect the accuracy of the results. In this research, image processing technique was used for better estimation of the spray traits, and to overcome the problem of droplet merger. The droplets were classified as non-merged and merged droplets based on their roundness, then the merged droplets were separated based on the average non-m
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Abstract
The research aims to diagnose the reality of applying the eighth requirement (operation) of the business continuity management system according to the international standard (ISO 22301: 2019), in the General Tax Authority, which is related to planning, implementing and controlling specific processes and procedures to address risks and opportunities, and the research adopted the checklist of the standard ( ISO 22301: 2019), in obtaining information, to measure the extent of application and documentation, the percentages and the weighted arithmetic mean were relied upon, and the research reached a set of result
... Show MoreWelcome to International Journal of Research in Social Sciences & Humanities (IJRSSH). It is an international refereed journal of Social Sciences, Humanities & Linguistics in English published quarterly, both print and online.
The aim of the research is to know the effect of financial leverage on the market value of the stock by applying it to a sample of private Iraqi commercial banks listed in the Iraqi Stock Exchange for the period (2010-2019) and to show the extent of that effect, based on the bank’s annual reports for the mentioned period through the use of financial leverage ratios represented b (Equity multiplier, cash balance ratio), its discussion, analysis, description, inferential description, and testing of research hypotheses,
A set of conclusions has been reached, the most important of which are: The research sample banks depend in their financial structures on borrowed funds in a greater proportion than their r
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