Background: This in vitro study compares a self-etch primer (SEP) to an etch-and-rinse (EaR) for bonding sapphire brackets by evaluation of the enamel etch-pattern, shear bond strength, amount of remnant adhesive and enamel surface damage following thermal and fatigue cyclic loading. Material and Methods: Ceramic (sapphire) brackets were bonded to 80 extracted human premolars using two enamel etching protocols: conventional EaR using 37% phosphoric acid (PA) gel (control), and a SEP (Transbond Plus). Each group was subdivided into two subgroups (n=20 teeth) according to the time of bracket debonding: after 24 h water storage or following 5000 thermo-cycles plus 5000 cycles fatigue loading, to determine the shear bond strength (SBS), adhesive remnant index (ARI score), with scanning electron microscopy (SEM) evaluation of enamel condition. Results: The control subgroups consistently exhibited significantly higher (p ˂ 0.05) SBS mean values (23.4-29.8 MPa) than the SEP subgroups (15.1-22.4 MPa) at both bracket debonding time points. However, the SEP subgroups yielded milder etch-patterns and attained SBS values above the minimum requirement range for clinical performance. In addition, the higher SBS of control subgroups was accompanied with higher ARI scores and enamel damage grades than SEP subgroups as confirmed by SEM. Thermocycling and fatigue significantly reduced the SBS of all subgroups, with a non-significant drop in the amount of adhesive residue or enamel damage. Conclusions: The use of SEP can be a suitable alternative to the conventional PA gel for sapphire bracket bonding as it maintains suitable bond strength and has the potential to produce both less remnant adhesive and enamel damage
This research aims to the possibility of evaluating the strategic performance of the State Board for Antiquities and Heritage (SBAH) using a balanced scorecard of four criteria (Financial, Customers, Internal Processes, and Learning and Growth). The main challenge was that the State Board use traditional evaluation in measuring employee performance, activities, and projects. Case study and field interviews methodology has been adopted in this research with a sample consisting of the Chairman of the State Board, 6 General Managers, and 7 Department Managers who are involved in evaluating the strategic performance and deciding the suitable answers on the checklists to analyze it according to the 7-points Likert scale. Data analysis re
... Show MoreThis research aims to the possibility of evaluating the strategic performance of the State Board for Antiquities and Heritage (SBAH) using a balanced scorecard of four criteria (Financial, Customers, Internal Processes, and Learning and Growth). The main challenge was that the State Board use traditional evaluation in measuring employee performance, activities, and projects. Case study and field interviews methodology has been adopted in this research with a sample consisting of the Chairman of the State Board, 6 General Managers, and 7 Department Managers who are involved in evaluating the strategic performance and deciding the suitable answers on the checklists to analyze it ac
... Show MoreResilient polymeric materials such as silicone elastomers are currently used for maxillofacial prostheses construction but the strength of these materials and their clinical performance need to be optimized with the addition of reinforcing fillers. This study investigates the effect of zirconia nanopowder addition on tear strength, tensile strength, elongation at break, Shore A hardness, surface roughness and cytotoxicity of VST-50 maxillofacial silicone. Silicone base was mixed with different amounts (1%, 2% and 3%) of zirconia nanopowder using a vacuum mixer. Silicone without filler was used as control for comparison. Scanning Electron Microscopy and Atomic Force Microscopy were utilized to assess the efficiency of high-shear vacuum mixin
... Show MoreThis research was carried out to evaluate the activity of crude juice of Olive on some cytogenetic parameters in mice like chromosomal aberration (CAs) and micronuclei formation(MN). The results showed that there was no significant difference between the crude juice (green and black)in CAs(3.77,4.10)and MN(0.25,0.25) in comparison with negative control (3.39,0.22)respectively. The interaction effect between the crude before and after treatment with mutagen MMC showed that the crude is one of the vital inhibitors of the mutagen by its ability in reducing the percentages of both the CAs and MN in bone marrow cells in mice.
Summary:This article discusses the topic of phraseological units with the names of wild animals in the Russian and Arabic languages in the aspect of their comparative semantic and cultural analysis, since a comparative analysis of the meanings of phraseological units of the Arabic and Russian languages, detection of coincidences and differences in the compared languages, is an important method for studying linguoculturology, since phraseological units represent a reflection of culture in the language
Currently and under the COVID-19 which is considered as a kind of disaster or even any other natural or manmade disasters, this study was confirmed to be important especially when the society is proceeding to recover and reduce the risks of as possible as injuries. These disasters are leading somehow to paralyze the activities of society as what happened in the period of COVID-19, therefore, more efforts were to be focused for the management of disasters in different ways to reduce their risks such as working from distance or planning solutions digitally and send them to the source of control and hence how most countries overcame this stage of disaster (COVID-19) and collapse. Artificial intelligence should be used when there is no practica
... Show Moreيعتبر "تاج الأشواك" أو نبات شوكة المسيح، وهو من نباتات الزينة الطبية ، ينتمي إلى جنس يوفوربيا. E. milii يحتوي كميات وفيرة من المركبات الفينولية ، التربينات، الستيرويدات والقلويدات. كانت الأهداف الرئيسية لهذه الدراسة هي فحص مستخلصات الفلافونويد والنانو فلافونويد ضد نوعين من خطوط الخلايا السرطانية. تم تصنيع مركبات الفلافونويد النانوية عن طريق تفاعل مركب الكيتوسان والماليك اسد. تم تحليل مركبات الفلافونويد ال
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