Background: Elastomeric chains are used to generate force in many orthodontic procedures, but this force decays over time, which could affect tooth movement. This study aimed to study the force degradation of elastomeric chains. Data and Sources: An electronic search on Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, LILACS, and PubMed was made, only articles written in English were included, up to January 2022.Study selection: Fifty original articles, systematic reviews, and RCTs were selected. Conclusion: Tooth movement, salivary enzymes, alcohol-containing mouthwash, whitening mouthwash, and alkaline and strong acidic (pH <5.4) solutions all have a significant impact on elastomeric chain force degradation. The force level of elastomeric chains degrades rapidly over time; however, the force degradation rate is slower in thermoset chains than in thermoplastic ones. An efficient tooth movement could be achieved by using a thermoset chain type with monthly replacement. Ethylene oxide and gamma sterilization methods are preferred to avoid the risk of cytotoxicity.
A mathematical model and associated computer program were developed to simulate the steady state operation of wiped film evaporators for the concentration of glycerol-water solution. In this model, various assumptions were made to facilitate the mathematical model of the wiped film evaporator. The fundamental phenomena described were: sensible heating of the solution and vaporization of water. Physical property data were coded into the computer program, which performs the calculations of this model. Randomly selected experiments were carried out in a small scale wiped film evaporator from ALVAL COMPANY, using different concentrations of the glycerol solution (10, 30 and 50 Wt. %) for different feed rates (30, 50, 80, 100 and 120 l/h) and
... Show MoreThe Shari'a of Islam is the end of the laws revealed by God, including the goodness of the servants in the pension and the restored. They are supported by the enemies of Islam, especially in these days when the Islamic Ummah is subjected to a fierce campaign by its enemy to repel it from its religion through what they claim from the rights of women, including the right to equality with men.
Islam came to announce to all mankind that women are part of life in society without which they can not imagine life for them. Islam did not leave women under the absolute authority of men, but raised their status and worked to liberate them, and these rights are divorced from her husband, does she have the right
It has become familiar to see alchemy as a methodological approach that combines conscious, diverse, psychological, social, structural, and discrete approaches in the communications technology that Marshall McLuhan found to be able to extend our bodies and senses, The media discourse has a deep and superficial structure produced by the first, with its social, cultural and historical backgrounds, in a context that connects the image with the word, as the "meanings are made" - everywhere, as described by Jonathan ) In fashion, in the arts as a whole, and from its "signs" Our analysis of «meaning», in the media, and communication through advertising, magazines, newspapers, television, and the Internet. Therefore, alchemy is preoccupied wi
... Show MoreInsulin resistance is a fundamental feature of obesity, diabetes, and cardiovascular diseases and contributes to many of the metabolic syndrome's abnormalities. It is defined as a subnormal reaction to normal insulin concentrations or a situation in which greater than normal insulin concentrations are necessary for normal response.
Shoot tip of Actinidia chinensis plant were excised and sterilized with mercuric chloride (Hgcl2) at concentration 0.1% for 5 min, then cultured on MS medium supplemented with benzeladinine BA at concentration (0.0,0.5,1.0,2.0,2.5) mg/l in multiplication stage Moreover, indole butyric acid IBA at concentration (0.0, 0.5,1.0,2.0,4.0) mg/l and (0.0,0.5,1.0,2.0) mg/l on solid and liquid solution media respectively in rooting stage were studied. All experiments have done under controlled conditions (25 ±2) Cº and 1000Lux light intensity for 16 hrs / day. Results revealed that supplementing the media with BA at concentrations 2.0 and2.5 mg/l was superior to give highest rate of shoot and number of leaves reached 5.8 /explant and 6.0 l
... Show MoreA graphene-based supercapacitors (SC) were manufactured. The main objective of this research was to use as possible as environmentally, clean and natural materials for the SC electrodes, electrolytes and the separators. The SC consisted of a multi-layer graphene (MLG); as the electrode material, prepared by mixing graphene powder with water/acetone mixture, then the solution deposited on metal foils (aluminum and copper) by chemical spray technique, which is a simple and inexpensive technique to prepare the MLG films. The spraying time was (2 and 4 minutes) for making two MLG films with different thicknesses. The electrolytes were used is (lemon juice, table salt dissolved in water, and distillated water). The separators were a commercia
... Show MoreContinuous functions are novel concepts in topology. Many topologists contributed to the theory of continuous functions in topology. The present authors continued the study on continuous functions by utilizing the concept of gpα-closed sets in topology and introduced the concepts of weakly, subweakly and almost continuous functions. Further, the properties of these functions are established.
Background: The aim of this study was to evaluate and compare the static frictional forces produced by monocrystalline ceramic (sapphire) bracket and polycrystalline ceramic bracket. Materials and methods: one hindered twenty brackets/segment of archwire combinations were used, each bracket/segment of archwire combination was tested 10 times. The tests were performed in a universal testing Instron machine. The data was submitted to in depended t-test. Results: The independent sample t-tests showed a highly significant difference in the static frictional forces between monocrystalline ceramic (sapphire) bracket and polycrystalline ceramic bracket. Conclusion: According to the biomechanical result gained from the present study, the monocryst
... Show MoreThe acquisition is of one of the methods utilized by the holding company to expand its activities and its control over other companies. Acquisition activity of the holding companies is particularly important to distinguish them from the rest of the commercial companies. Economic changes in Iraq and the country's need for foreign capitals havethe multiple and diverse of experiences, leading to, besides the need for a certain technique to increase the competitiveness and financial efficiency capabilities in companies, push the economy towards openness and allow for foreign companies, like national companies, to exercise its business in Iraq and to revitalize the financial market to ensure companies enter new markets through whi
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