388 research outputs found
A note on convergence of Peck-Shell and Green-Lin mechanisms in the Diamond-Dybvig model
We study the e¤ects of population size in the Peck-Shell analysis ofbank runs. We nd that a contract featuring equal-treatment for al-most all depositors of the same type approximates the optimum. Becausethe approximation also satis es Green-Lin incentive constraints, when theplanner discloses positions in the queue, welfare in these alternative spec-i cations are sandwiched. Disclosure, however, is not needed since ourapproximating contract is not subject to runs.keywords: bank fragility, role of population size, role of aggregate uncer-tainty
The surface treatment of dental ceramics: an overview
This review proposes to present some aspects of dental ceramics surface treatments, which involve the related physical and mechanical properties, as well as new technologies. The correct cementation of prosthetic restoration is essential for clinical success. However, the adhesive technique is a very recent procedure and clinicians should have a more detailed knowledge about the technique and related materials so that they can use them in their day-to-day clinical practice. Information about the the principles, indications and contraindications of adhesive cementation technique were obtained from the literature. The studies indicate that the adhesive system seems to be a valid option for fixed prosthesis cementation, since it has several advantages over conventional cementation method, especially in all-ceramic restorations. In clinical practice, the clinician should always keep in mind the characteristics of the material they are working with, so that they can select the best technique and the best cement for each clinical situation. Although more research is required in this field, there are no scientific reasons to contraindicate in routine practice
Enamel evaluation by scanning electron microscopy after debonding brackets and removal of adhesive remnants
The bonding of accessories in the dental crown during the orthodontic treatment creates microporosities, thus promoting micromechanical retention of the adhesive to the enamel structure. After debonding brackets, at the end of the active orthodontic treatment, a certain amount of adhesive remnants must be mechanically removed from the enamel. The objective of this study was to compare, by means of scanning electron microscopy, three different methods to remove the adhesive remnants after orthodontic bracket removal. An experimental analytical study was conducted on human premolar specimens, extracted within a year or less. The preparation of the enamel was carried out with the application of 35% phosphoric acid and Transbond XT Light Cure Adhesive Primer® adhesive. Edgwise Standart prescription brackets, slot .022 ?(Morelli Orthodontia) were glued to the enamel using Transbond XT® bonding resin. The brackets were placed on the center of the vestibular face of the clinical crown, and a 300-gram pressure was exerted against the surface of the enamel, measured with an orthodontic dynamometer. The brackets were debonded with adhesive removing pliers, and the samples were divided into groups, according to the protocol used for adhesive remnant removal: high-speed multi-laminated drill bit, low-speed multi-laminated drill bit, and low-speed glass fiber. After removal of the adhesive remnants, the samples went through scanning electron microscopy, obtaining electro micrographs with a magnification range of 150 X, 500 X, and 2,000 X. The tested method showed that the best effectiveness for the removal of the adhesive remnants after bracket debonding was the use of a tungsten carbide multi-laminated high speed, followed by the use of a tungsten carbide multi-laminated, low-rotation drill. The use of fiberglass drill alone has proved to be inefficient for clinical use, given the large amounts of adhesive remnants it leaves on the enamel. All methods evaluated in this study proved to be inefficient for total removal of adhesive remnants from the enamel
Effect of saliva contamination on cementation of orthodontic brackets using different adhesive systems
The enamel condition and the quality of surface are points that need to be considered for achieving optimal efficiency in the treatment with orthodontic brackets. The aim of this study was to assess the immediate bond strength of metallic brackets cemented to dental. Forty human premolars were double-sectioned, placed in PVC matrices and randomly divided into 10 groups (n=8). They received artificial saliva contamination before or after the application of adhesive systems, except for the control groups. The metallic brackets were cemented using two orthodontic cements (Transbond? Plus Color Change, 3M Unitek e Transbond? XT Light, 3M Unitek). The specimens were subjected to mechanical shear bond strength testing and classified according to the fracture pattern. The results were analyzed using a two-way ANOVA and Tukey?s test for multiple comparisons (p<0.05). ANOVA analysis showed statistically significant differences between the groups (p=0.01). The Tukey?s multiple comparison test indicated statistically significant difference between G6 and G7 groups (p<0.05). A high prevalence of adhesive failure in the groups receiving the hydrophobic adhesive system. The saliva contamination prior to the application of a hydrophobic simplified conventional adhesive system was responsible for decreasing the immediate bond strength values of brackets cemented on the dental enamel
Preheated restorative composite resin for luting ceramic laminate veneers : an optimized technique report
Resin cements are traditionally used to lute ceramic laminate veneers due to their lower viscosity, which facilitates a fast restoration seating. However, resin cements have lower mechanical properties compared to restorative composite resins. Thus, rest
Perfil da pesquisa em finanças no Brasil
UnavailableEste trabalho analisa uma amostra de 462 artigos da área de
finanças publicados entre 1974 e 2000 na RAC, RAE, RAUSP, RBE e
RBMEC, além de 205 artigos incluídos nos Anais do ENANPAD. A
maioria dos artigos é de um único autor. Mais de 70% dos autores
publicou apenas um artigo, número maior do que o previsto pela
teoria bibliométrica. A produtividade dos autores nacionais está
mais concentrada em poucos indivíduos e é mais baixa do que no
exterior. Os artigos dos autores que publicaram três ou mais artigos
em periódicos têm idade média maior do que a de artigos de
autores igualmente prolíficos nos Anais. A maioria dos artigos em
periódicos dos autores prolíficos vem da UFRJ, USP e PUC/RJ. O
IBMEC aparece bem, mas os artigos estão concentrados na
RBMEC, nas décadas de 70 e 80. Já nos Anais, os autores da
UFRGS aparecem de forma expressiva junto aos da UFRJ e da
PUC/RJ que, juntos, respondem por 79% da produção dos autores
com três ou mais artigos publicados nos Anais
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