Background: This study was formulated to compare the effect of 5%hydrofluoric acid in comparison to 37%phosphoric acid with and without the application of silane on bond strength of composite to porcelain. Materials and Methods: Specimen preparation was divided in to two phases, metal-disks fabrication (8mm-diameter and 4mm-thickness) and ceramic veneering. Thirty two specimens were prepared, sandblasted with 50 μm aluminum oxide, and divided into four groups of eight samples. Groups I and III were etched with 37%phosphoric acid while groups II and IV were etched with 5%hydrofluoric acid; and groups I and II were silaneted while groups III and IV were not. Heliobond, and resin composite were applied to each specimen using a plastic transparent split mold (4mm- diameter and 4mm-height). Specimens were stored in distilled water for 24 hours then thermocycled for 100 cycles. Shear bond strength was determined by a Zwick universal machine at a cross-head speed 5 mm/minute. Results: Mean shear bond strength values were 21.02(group I), 23.31(group II), 4.00(group III), and 18.60(group IV). Paired-t revealed that specimens treated with 5%hydrofluoric acid were significantly higher than those treated with 37%phosphoric acid regardless the use of silane. The use of silane dramatically enhanced the bond strength of composite resin to porcelain for both acids. All specimens treated with 37%phosphoric acid without silane showed adhesive failure, while those treated with 5%hydrofluoric acid showed mostly cohesive failure within ceramic. Conclusion: Silane improved the shear bond strength of composite to ceramic, and hydrofluoric acid performed greater bond strength compared to phosphoric acid.
Many attempts have been made to modify the surface of orthodontic micro-implants and prevent the development of microbes by coating them with antimicrobial nanoparticles (NPs). The purpose of the present study was to evaluate the cytotoxicity of different NPs, namely, TiO2 and zinc oxide (ZnO) NPs, that are used to coat titanium orthodontic micro-implants.
Thirty orthodontic micro-implants were included in this study. Those were divided into three groups: control group without coating, TiO2-coated orthodontic micro-implants, and TiO2- and ZnO-coated orthodontic micro-implants. Scann
The Humidification-Dehumidification (HDH) desalination technique offers a viable solution for providing freshwater to populations in water-scarce, remote areas. This study experimentally investigates a novel humidifying method by cross airflow over water-wetted pottery tubes, which function as a humidifier, incorporating a thermoelectric cooler to condense water vapor for freshwater production. To optimize freshwater production and thermal efficiency, meticulous design of these components and appropriate operational parameters are selected. Experiments were performed in three environments with differing temperatures and relative humidity levels, while air velocity varied from 1.02 to 1.89 m/s, and thermoelectric cooler voltage ranged from 6
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The purpose of this paper is to study a new types of compactness in the dual bitopological spaces. We shall introduce the concepts of L-pre- compactness and L-semi-P- compactness .
Alms (or Zakat) is one of the Pillar of Islam and it was atask imposed on
Muslims. Becomes of the importance of this task and its influence on the human
Psychic in particular and on the Society in general this study aims at Studying the
words that it refers to in the Holy Quran, At the beginning the researcher has
introduced the words it refers to, and the significance of each in the Holy Quran and
the Speciality of each one of such words, then the Structures they donet have been
also introduced, whether such structures are descriptive, adverbial or verbal.This was
introduced in addition to explaining the influence of changing the Shape of such
words in emphasizing the meaning and the influence of Portraiting styl
he public federal budget of the state includes estimated figures for state revenues and expenditures for the next fiscal year. The estimation process is one of the main parts of the preparation of the general budget of the state and the accuracy in the estimation of revenues and expenditures of the most important principles that should be based on the process of making estimates and should not overestimate the assessment process to ensure the availability of funds in the future in all cases, which lead to unfair distribution of allocations, so the research aims to study The case of preparing the budget in the Directorate and how to estimate the expenditure in, by the analysis of operating budgets and identify deviations in the implementa
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Regression testing being expensive, requires optimization notion. Typically, the optimization of test cases results in selecting a reduced set or subset of test cases or prioritizing the test cases to detect potential faults at an earlier phase. Many former studies revealed the heuristic-dependent mechanism to attain optimality while reducing or prioritizing test cases. Nevertheless, those studies were deprived of systematic procedures to manage tied test cases issue. Moreover, evolutionary algorithms such as the genetic process often help in depleting test cases, together with a concurrent decrease in computational runtime. However, when examining the fault detection capacity along with other parameters, is required, the method falls sh
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This research aims to identify the reality of Sino-Russian relations after 2013, and to study the most important motives and determinants that affected the nature of these relations. The research was based on the criterion of national interest in interpreting and understanding relations between China and Russia, on the basis that national interest is what determines the state of cooperation and dependence, or the state of competition and difference. The research was based on the hypothesis that Sino-Russian relations after 2013 witnessed many factors and variables, some of which represented motives for strengthening relations between the two countries, and others represented obstacles that limit the level of cooperation and interaction betw
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The problem with the search at the reduction of adoption of new products, as there are three hypotheses of research have been formulated , the first one is no significant correlation between the religious and differences to customers and adopt new products, and This Study Aimed To Investigate The Relationship Between Religious differences for customers And New Products Adoption, Applied On Arab Mall Commercial Customers/ Egypt, an Analytical Model Is Developed As Guideline To Test The The Relationship Between Religious differences for customers And New Products Adoption, Aquantative Method With Deductive Approach Were Chosen In This Research . In Order To Collect Primary Data, A questionnaire Is
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Abstract: This research deals with the developing of power and different abilities (military, security, economy, technology and scientific excellence) The research shows that the excellence of the Chinese economy and its development , had a positive reflection on the other powers and abilities , it means it is a base of development in all fields. The development in power and Chinese military abilities had a clear effect on Chinese strategic creed , and that what the research deals with in some details. The research also deals with developing Chinese nuclear abilities. The research doesn't ignore the security eye that indicates to the protection of the state sovereignty, concentrating on the unity and safety Chinese lands. The res
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