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Microshear Bond Strength of Self-etching Systems Associated with a Hydrophobic Resin Layer

MORAES, Andre Guaraci De Vito; FRANCCI, Carlos; CARVALHO, Ceci Nunes; SOARES, Silvio Peixoto; BRAGA, Roberto Ruggiero
Fonte: QUINTESSENCE PUBLISHING CO INC Publicador: QUINTESSENCE PUBLISHING CO INC
Tipo: Artigo de Revista Científica
Português
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Purpose: To evaluate in vitro the microshear bond strength of adhesive systems applied to dentin according to manufacturers` instructions, associated or not with a hydrophobic layer of unfilled resin. Materials and Methods: Six self-etching adhesives (Clearfil SE Bond, Kuraray Medical; AdheSE, lvoclar Vivadent; Xeno III, Dentsply; I Bond, Heraeus-Kulzer; Bond Force, Tokuyama; Futurabond DC, Voco) were tested. The labial dentin of sixty bovine incisors was exposed, and the teeth were divided into two groups according to the application or not of an extra hydrophobic resin layer (Scotchbond Multi Purpose Plus, bottle 3). Six composite cylinders (Filtek Z250, 3M ESPE) were built up on each treated surface. Specimens were stored in distilled water at 37 C for 24 h and then subjected to the microshear bond strength test in a universal testing machine at a crosshead speed of 0.5 mm/min. Microshear bond strength values were analyzed by 2-way ANOVA and Tukey`s post-hoc test. Failure mode was determined using a stereomicroscope under 20X magnification. Results: The application of the hydrophobic resin layer did not affect bond strength, except for AdheSE. However, the bond strengths with the hydrophobic layer were similar among the six tested systems (Clearfil: 17.1 +/- 7.9; AdheSE: 14.5 +/- 7.1; Xeno III: 12.8 +/- 7.7; I Bond: 9.5 +/- 5.8; Bond Force: 17.5 +/- 4.1; Futurabond: 7.7 +/- 2.3). When used as recommended by the manufacturers...

Shear Bond Strength and Ultrastructural Interface Analysis of Different Adhesive Systems to Bleached Dentin

FERREIRA, Ernando A.; SOUZA-GABRIEL, Aline E.; SILVA-SOUSA, Yara T. C.; SOUSA-NETO, Manoel D.; SILVA, Ricardo G.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
Português
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Background: It remains unclear as to whether or not dental bleaching affects the bond strength of dentin/resin restoration. Purpose: To evaluated the bond strength of adhesive systems to dentin submitted to bleaching with 38% hydrogen peroxide (HP) activated by LED-laser and to assess the adhesive/dentin interfaces by means of SEM. Study design: Sixty fragments of dentin (25 mm(2)) were included and divided into two groups: bleached and unbleached. HP was applied for 20 s and photoactivated for 45 s. Groups were subdivided according to the adhesive systems (n = 10): (1) two-steps conventional system (Adper Single Bond), (2) two-steps self-etching system (Clearfil standard error (SE) Bond), and (3) one-step self-etching system (Prompt L-Pop). The specimens received the Z250 resin and, after 24 h, were submitted to the bond strength test. Additional 30 dentin fragments (n = 5) received the same surface treatments and were prepared for SEM. Data were analyzed by ANOVA and Tukey`s test (alpha = 0.05). Results: There was significant strength reduction in bleached group when compared to unbleached group (P < 0.05). Higher bond strength was observed for Prompt. Single Bond and Clearfil presented the smallest values when used in bleached dentin. SEM analysis of the unbleached specimens revealed long tags and uniform hybrid layer for all adhesives. In bleached dentin...

"Influência da fluorose dental na resistência de união de sistemas adesivos ao esmalte: análise em microscopia eletrônica de varredura e teste de microtração"; Influence of dental fluorosis on the bond strength of adhesive system to enamel

Peixoto, Luciana Faria Sanglard
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 11/12/2006 Português
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Objetivou-se observar a influência da fluorose dental nas características do padrão de condicionamento ácido e na penetração de sistemas adesivos no esmalte, por microscopia eletrônica de varredura (MEV) e na resistência de união de sistemas adesivos ao esmalte, por teste de microtração. Para tal, 196 dentes permanentes posteriores foram classificados seguindo o Índice Thylstrup e Fejerskov (TF= 0, 1 e 4), sendo selecionados 69 deles. Adesivos de 2 passos, um autocondicionante, Clearfil SE Bond®, e um de condicionamento ácido total, Adper Single Bond 2® foram usados. Para análise em MEV do padrão de condicionamento e das réplicas de resina, 27 pré-molares foram seccionados no sentido mesiodistal e divididos em 9 grupos (n=3). As superfícies vestibulares foram selecionadas e seccionadas no sentido longitudinal, sendo metade para cada análise. Os espécimes pertencentes ao grupo do ácido fosfórico foram condicionados com tempos de 15 ou 60 segundos, lavados com ar/água por 20 segundos e secos. Os espécimes do grupo Clearfil SE Bond® receberam aplicação do primer do material, e em seguida, tratamento para removê-lo. Para obter as réplicas de resina, as superfícies foram delimitadas (2x2mm) com fita isolante...

Resistência ao cisalhamento de selante associado a dois sistemas adesivos, após contaminação salivar: influência da fotopolimerização individual e simultânea; Shear bond strength of a pit-and-fissure sealant associated with two adhesive systems after salivary contamination: influence of individual and simultaneous light curing

Silva, Jaciara Miranda Gomes da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 06/08/2007 Português
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Este trabalho teve por objetivo avaliar "in vitro" a resistência ao cisalhamento de um selante resinoso (Fluroshield - F) em associação com um sistema adesivo total-etch (Adper Single Bond 2-SB) e um self-etching (Clearfil S3 Bond-S3) em condições de contaminação salivar, comparando dois protocolos de fotopolimerização: individual do sistema adesivo e, em seguida, do selante ou simultânea de ambos materiais conjuntamente. Superfícies mesiais e distais de 45 terceiros molares humanos hígidos foram incluídas e planificadas, o sítio de adesão delimitado (Ø 3mm) e os corpos-de-prova alocados aleatoriamente em 6 grupos experimentais (n=15), de acordo com o tratamento empregado: I- F aplicado sobre o esmalte condicionado com ácido fosfórico a 37% (controle). Os demais grupos foram contaminados com saliva (0,01ml por 10 s) e a seguir foram aplicados: II- SB e F fotopolimerizados separadamente; III- SB e F fotopolimerizados conjuntamente; IVS3 e F fotopolimerizados separadamente; V- S3 e F fotopolimerizados simultaneamente; VI- F aplicado sem associação com adesivos sobre o esmalte condicionado e contaminado. A seguir, um cilindro de selante foi confeccionado com o auxílio de uma mesa metálica e de matriz de teflon bipartida sobre o sítio de adesão. Após armazenamento durante 24 horas a 37°C em água destilada...

Avaliação in vitro da microtração de sistemas adesivos à dentina irrigada com soluções endodônticas: Influência da degradação da interface adesiva; In vitro evaluation of systems on microtensile bond strength to orrogated dentin with endodontic solutions. Adhesive interface degradation influence

Galafassi, Daniel
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 27/01/2009 Português
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O objetivo desse trabalho foi avaliar a influência da resistência de união de sistemas adesivos à dentina irrigada com substâncias endondônticas, após a degradação da interface adesiva e análise morfológica da interface adesiva por meio de microscopia eletrônica de varredura (MEV). Foram selecionados sessenta terceiros molares, que tiveram a porção oclusal removida e planificada expondo a dentina profunda. Os espécimes foram irrigados com hipoclorito de sódio a 2,5% por 30 minutos e em seguida em EDTA 17% por 5 minutos. Após a irrigação da superfície detinária os dentes foram divididos aleatoriamente em seis grupos (n = 10) de acordo com o sistema adesivo empregado: G1 e G2 - Clearfil (Kuraray); G3 e G4 - Single Bond 2 (3M) e G5 e G6 - XP Bond (Dentsply). Após a aplicação do sistema adesivo, foi confeccionado um platô de resina composta Z100 (3M). A degradação da interface adesiva foi realizada por meio de estocagem em água deionizada/ciclagem térmica: 24 horas de estocagem em água deionizada/nenhum ciclo (grupos G1, G3 e G5) e 6 meses de estocagem em água deionizada/12.000 ciclos (grupos G2, G4 e G6). Após os períodos pré-estabelecidos em cada grupo, os conjuntos dente/resina foram seccionados de forma a se obter 4 palitos de aproximadamente de 1mm2...

A importância de alguns adesivos dentais e de vários tratamentos da superfície sobre a dentina humana in vitro. Análise da resistência adesiva por micro-cisalhamento; The relevance of some dental adhesives and different surface instrumentations on human dentin (in vitro). Micro-shear bond strength analyses

Macedo, Manoel Roberto de Paula
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 05/12/2008 Português
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O objetivo deste trabalho foi estudar a ação sobre a dentina humana (in vitro) de vários tratamentos de superfície: Lixa, IADR-GM, CVDt e CVDi e de alguns adesivos dentais: Adper Sigle Bond 2 (SB), Clearfil SE Bond (CF) e Adper Prompt L-Pop (PL) avaliando: rugosidade e resistência adesiva por micro-cisalhamento. Foram utilizados 72 terceiros molares hígidos que foram divididos ao meio. As superfícies oclusais das 144 metades dentais foram removidas e padronizadas com Lixa #600. Após receberem os tratamentos de superfície citados, foi avaliada a rugosidade média superficial (Ra) da dentina. Em seguida realizou-se a hibridização e a confecção dos cilindros de resina composta (RC) para finalizar o preparo dos corpos de prova (cps). Após armazenagem de 24h em água destilada a 370C realizou-se o teste de micro-cisalhamento com velocidade de deslocamento de 1mm/min. Os resultados foram submetidos a testes de analise estatística (ANOVA) onde foi comprovado que a menor Ra foi encontrada nas superfícies instrumentadas com Lixa #600 seguida pelo CVDi, IADR-GM que apresentaram rugosidade intermediaria e se igualaram e pelo CVDt que produziram as superfícies mais rugosas. Já para o tratamento de superfície, o CVDi foi que apontou os piores valores de resistência de adesão que com Lixa e IADR-GM. Nos resultados para os adesivos...

Resistência ao cisalhamento de sistemas adesivos autocondicionantes e de condicionamento total aplicados em dentina, em profundidades diferentes; Shear bond of different self etch and total etch adhesive systems applied in different dentin depth

Rosa, Ana Carolina Maito Villela
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 12/08/2009 Português
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Objetivos: O propósito deste estudo foi o de avaliar, quanto à resistência ao cisalhamento, o comportamento de quatro sistemas adesivos, Adper Single Bond 2, Adper Prompt L-Pop, Magic Bond DE e Self Etch Bond em função das faces vestibulares e linguais e da profundidade da dentina. Material e Método: Quarenta terceiros molares extraídos tiveram suas raízes removidas e as coroas seccionadas no sentido mésio-distal. As faces vestibulares e linguais foram incluídas em anel de PVC/resina acrílica e divididas em grupos, um vestibular e um lingual para cada adesivo selecionado. Para se avaliar as diferentes profundidades de dentina, os mesmos corpos-de-prova preparados para a avaliação da resistência adesiva da camada superficial foram utilizados. Os espécimes foram então identificados e desgastados, posterior e seqüencialmente, para as profundidades de 0,5, 1,0, 1,5, 2,0mm. Cada profundidade foi avaliada por meio do método de cisalhamento ISO TR 11405, usando uma máquina universal de testes (EMIC-2000), regulada a 0,5mm/minuto e célula de carga de 200 Kgf. Os resultados foram submetidos à análise estatística de variância (Testes ANOVA, Tukey e Scheffé). Resultados: Houve diferença estatística significante (p<0...

Microtração de sistemas adesivos autocondicionantes em dentina desmineralizada de dentes decíduos após preparo cavitário com laser de Er: YAG: avaliação in vitro; Microtensile bond strength of selfetch adhesive systems in demineralised dentin of primary teeth after Er: YAG laser irradiation: in vitro evaluation

Almeida, Cintia Guimaraes de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/06/2011 Português
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36.59%
O objetivo deste estudo foi avaliar a resistência à microtração de adesivos autocondicionantes em dentina desmineralizada de dentes decíduos após a irradiação com laser de Er: YAG. Oitenta e dois molares decíduos tiveram a porção oclusal seccionada transversalmente e os espécimes foram desgastados com lixas de carbeto de silício de granulações 360 e 600 até expor a dentina. Os 60 espécimes utilizados no teste de microtração foram preenchidos com resina composta fotopolimerizável na região correspondente à câmara pulpar, isolados com esmalte cosmético mantendo a superfície dentinária exposta e, em seguida imersos em solução desmineralizante por seis dias em estufa a 37° C para indução de lesão de cárie artificial em dentina. Após a desmineralização, os espécimes foram preparados com laser de Er: YAG (n=30) com os parâmetros de 260 mJ, 3 Hz, 47 J/cm2, 0,81W e com broca de aço esférica em baixa rotação (n=30). Sobre as superfícies preparadas foram aplicados três sistemas adesivos autocondicionantes Clearfil SE Bond (Kuraray); Adper™ Easy One (3M ESPE) e Adper™ SE Plus (3M ESPE) e, em seguida foram confeccionados platôs de resina composta Z 250. Após termociclagem (500 ciclos)...

Avaliação da resistência de união de restaurações de resina composta com diferentes sistemas adesivos, em dois tempos de armazenamento; Composite resin bond strength with different dentin-bonding agents in two storage times

Dellazzana, Fernando Zurlo; Coelho de Souza, Fábio Herrmann; Klein Júnior, Celso Afonso
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
Português
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36.6%
A degradação hidrolítica dos adesivos dentinários pode infl uenciar a resistência de união das restaurações de resina composta ao longo do tempo. O objetivo deste trabalho é avaliar a influência do tempo de armazenamento associada à termociclagem e do tipo de adesivo dentinário empregado sobre a resistência de união de restaurações de resina composta. Foram utilizados 20 molares hígidos, os quais foram divididos em 2 tempos de avaliação (24 horas e 6 meses + termociclagem). Cada dente teve a dentina relativa à superfície oclusal exposta, a qual recebeu 3 corpos de prova de resina Flow com os sistemas adesivos: Scotchbond multiuso (3M/ESPE – Grupo 1), ClearFil SE Bond (Kuraray – Grupo 2) e Adper Single Bond (3M/ESPE – Grupo 3). Após o teste de microcrocisalhamento, os dados foram analisados estatisticamente pelos testes ANOVA, Tukey e t-student (α =0,05). Os resultados mostraram que os adesivos Scotchbond multiuso, ClearFil SE Bond e Single Bond não apresentaram diferenças na resistência de união em 24 horas de armazenamento. Após 6 meses, o adesivo ClearFil SE Bond obteve resistência superior ao Scotchbond multiuso. O adesivo Scotchbond multiuso sofreu redução na resistência de união após 6 meses de armazenamento. Os adesivos ClearFil SE Bond e Single Bond não sofreram influência do tempo de armazenamento e da termociclagem.; Water degradation of dentin bonding agents may infl uence bond strength in composite resin restorations after some periods of time. The aim of this study was to evaluate the infl uence of storage time with thermociclyng and type of dentin bonding agents used on the composite resin restorations microshear bond strength. Twenty molars were used and divided into two evaluation periods (24 hours and 6 months...

Experimental and theoretical investigations of C-C, C-H and C-S bond activations of nitriles using zerovalent nickel; Experimental and theoretical investigations of carbon-carbon, carbon-hydrogen and carbon-sulfur bond activations of nitriles using zerovalent nickel

Li, Ting (1982 - ); Jones, William D. ; Ateşin, Tülay Aygan (1976 - ); Grochowski, Matthew Robert (1975 - )
Fonte: University of Rochester. Publicador: University of Rochester.
Tipo: Tese de Doutorado Formato: Number of Pages:xx, 446 leaves : ill. (some col.)
Português
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Thesis (Ph. D.)--University of Rochester. Dept. of Chemistry, 2011.

Chapters 2-3 were co-authored with Tülay A. Ateşin. Chapter 7 was co-authored with Matthew R. Grochowski.; [Ni(dippe)H]2 complex has been reacted with a variety of carbon nitriles. Upon mixing with substrates, it releases H2 to generate the 14-electron fragment [Ni(dippe)], which is proposed to be the active species in bond activations. In the reaction with acetonitrile, initially the η2-nitrile complex was observed, which upon heating or photolysis leads to the C-CN bond activation product Ni(dippe)(CH3)(CN). No product from C-H bond cleavage was seen and the independently synthesized Ni(dippe)(H)(CH2CN) complex was very unstable and can only exist at low temperature. Computational studies using DFT calculation methods showed that the C-CN bond activation is favored exclusively over the C-H bond activation due to the strong thermodynamic driving force and slightly lower kinetic barrier. In reactions with aromatic nitriles, the [Ni(dippe)] fragment first coordinates η2 to the nitrile C≡N and/or C=C moiety. Rearrangement then occurs to give the C–CN oxidative addition product Ni(dippe)(Aryl)(CN). Both experimental and DFT calculation results have shown that an η2-arene complex with nickel coordinated to the C=C double bond next to the cyano substituent is the crucial intermediate leading to C–CN bond activation. Furthermore...

I. Energetics of C–H bond activation of functionalized hydrocarbons. II. C–H and C–CN bond activation of acetonitrile and benzonitrile; Energetics of C–H bond activation of functionalized hydrocarbons. II. C–H and C–CN bond activation of acetonitrile and benzonitrile; C–H and C–CN bond activation of acetonitrile and benzonitrile; II. C–H and C–CN bond activation of acetonitrile and benzonitrile

Evans, Meagan Elizabeth (1981 - ); Jones, William D.
Fonte: University of Rochester Publicador: University of Rochester
Tipo: Tese de Doutorado Formato: Illustrations:ill.; Number of Pages:xvii, 226 leaves
Português
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Thesis (Ph. D.)--University of Rochester. Dept. of Chemistry, 2011.; Several transition-metal systems have been used to establish correlations between metal-carbon and carbon-hydrogen bonds. In the following studies, the [Tp’RhL] fragment where Tp’ = tris(3,5-dimethylpyrazolyl)borate and L = neopentyl isocyanide, is used to investigate C–H bond activation of molecules with strong C–H bonds. The first study (Chapter 2) examines C–H bond activation of fluorinated aromatic hydrocarbons. Photolysis of the precursor, Tp’RhL(carbodiimide) in neat fluoroarene resulted in C–H activation products of the type, Tp’RhL(arylF)H. Both the kinetic and thermodynamic selectivities of rhodium for different C–H bonds on the fluorinated aromatic were examined. A strong thermodynamic preference was observed for C–H activation ortho to two fluorine atoms as opposed to one. Competition experiments along with ΔGre≠ values allow for the determination of relative Rh–Caryl bond strengths and illustrate the large ortho fluorine effect on the strength of the Rh–Caryl bond. This study was the first to quantize experimentally the effect of an ortho fluorine on the strength of the metal–carbon bond. In a similar study...

Influência da terapia endodôntica e do envelhecimento artificial acelerado na resistência de união de pinos de fibra de vidro à dentina intrarradicular; Influence of endodontic therapy and artificial accelerated aging on fibreglass post bond strength to intraradicular dentine

Santana, Fernanda Ribeiro
Fonte: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Ciências da Saúde (FM); Faculdade de Medicina - FM (RG) Publicador: Universidade Federal de Goiás; Brasil; UFG; Programa de Pós-graduação em Ciências da Saúde (FM); Faculdade de Medicina - FM (RG)
Tipo: Tese de Doutorado Formato: application/pdf
Português
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Aim: To evaluate in vitro the influence of root canal instrumentation techniques, endodontic irrigants, endodontic sealers and artificial accelerated aging on fibreglass post bond strength to bovine intraradicular dentine. Methodology: Part 1. 120 bovine incisors were divided into 12 experimental groups (n=10) resulting from the interaction among 3 study factors: root canal instrumentation technique (RCPSS- root canal preparation with stainless steel instruments - KFile; RCPNiTi- root canal preparation with K3 Nickel-Titanium instruments), endodontic irrigant (NaOCl- 1% sodium hypochlorite; CHX- 2% chlorhexidine; O3- 1.2% ozonated water) (in all samples 17% EDTA was used to remove the smear layer) and specimens artificial accelerated aging (Immediate, test with no aging; Mediate, test performed after 2 months of water storage at 37°C). After root canal preparation, endodontic filling was not performed. Fibreglass posts were cemented with self-adhesive resin cement (RelyX U100, 3M-ESPE) and roots were cross-sectioned to obtain two slices of each third. Samples were submitted to micropush-out test and bond strength values (MPa) were analyzed by ANOVA in a split-plot arrangement and Tukey’s test (α = 0.05). Failure modes were evaluated under a confocal microscope. Part 2. 60 bovine incisors were divided into 6 experimental groups (n=10) resulting from the interaction between 2 study factors: endodontic sealer (Sx- Sealapex; S26- Sealer 26; AHAH Plus) and specimens artificial accelerated aging (Immediate...

How Firms Use Domestic and International Corporate Bond Markets

Gozzi, Juan Carlos; Levine, Ross; Martinez Peria, Maria Soledad; Schmukler, Sergio L.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
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This paper provides the first comprehensive documentation of how firms use domestic and international corporate bond markets. Debt issues in domestic and international markets have different characteristics, not explained by differences across firms or countries. International issues tend to be larger, of shorter maturity, denominated in foreign currency, include more fixed rate contracts, and entail lower yields. These patterns remain when analyzing issues by firms from countries with more developed domestic markets and higher financial integration, and even when comparing issues conducted by the same firm in different markets. These findings are consistent with the views that (1) frictions limit the ability of investors and firms to enter into certain contracts in certain markets, (2) domestic and international markets provide distinct financial services and firms use them as complements, and (3) firms with access to domestic and international markets enjoy advantages relative to those that rely solely on domestic markets.

Turkey - Corporate Bond Market Development : Priorities and Challenges

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Português
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The study is in response to a request by the Capital Markets Board of Turkey to assist them in developing the corporate bond market in line with best practices globally. The objective of this study is to carry out an assessment of the status of the corporate bond market in Turkey. The study identifies key impediments and solutions to sustainable development, and it presents a roadmap to address the key impediments to the development of a dynamic and robust corporate bond market. This study provides a comprehensive review of the Turkish corporate bond market: chapter two provides an overview of the Turkish economy and financial sector; chapter three discusses key impediments to the vibrant development of the corporate bond; chapter four looks at the Turkish bond market within global bond markets and gives a review of the Turkish government bond market; chapter five discusses issues relating to the investor base, factors constraining the growth of a broad and diversified investor base are highlighted; chapter six provides an overview of derivatives market in Turkey and discusses its important role in enhancing liquidity in the secondary markets for government and corporate bonds. The study concludes with a recommended roadmap to develop the corporate bond market in chapter seven. The annexes cover the latest corporate bond offerings in Turkey and examine the expected transaction costs. Survey details of the survey are also in the annex...

Malaysia : Bond Market Development

International Monetary Fund; World Bank
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
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This paper pertains to the bond market development in Malaysia, and provides an overview of the market scenario in the country. Malaysia has been successful in developing the capital markets, particularly bond markets, in the recent past. Now, it faces the challenge of how to improve broader access and efficiency of the bond market. A high degree of investor concentration, dominated by government pension funds, plays a significant role in impeding the growth of higher-yield bond market. The role of the government in stimulating the growth of the bond markets should be now shifted toward encouraging more diversity. In order to promote risk diversity, significant measures should be taken to increase competition on the demand side. Another important challenge for the bond markets going forward is improving transparency to make them more attractive to a broader constituency. To improve liquidity and transparency, the authorities should encourage the establishment of open, independent electronic platforms that integrate price search...

Global Liquidity and External Bond Issuance in Emerging Markets and Developing Economies

Feyen, Erik; Ghosh, Swati; Kibuuka, Katie; Farazi, Subika
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Trabalho em Andamento
Português
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Using the universe of all externally issued bonds by corporates and sovereigns in emerging and developing economies during 2000-14, this paper analyzes various issuance trends, including the unprecedented post-crisis surge. The paper focuses on external issuance at the country-industry and individual bond levels and finds that global factors matter greatly for emerging and developing economies issuance. A decrease in U.S. expected equity market (or interest rate) volatility, U.S. corporate credit spreads, and U.S. interbank funding costs and an increase in the Federal Reserve’s balance sheet (i) raise the odds that the monthly issuance volume of a country-industry is above its historical average; (ii) decrease individual bond yields and spreads; and (iii) raise bond maturities, after controlling for country pull factors, bond characteristics (for example, type of issuer, industry, and riskiness). Additionally, we document support that the risk-taking channel of exchange rate appreciation also operates for external bond issuance. Moreover...

Bond strengths between composite resin and auto cure glass ionomer cement using the co-cure technique

Knight, G.; McIntyre, J.; Mulyani
Fonte: Australian Dental Assn Inc Publicador: Australian Dental Assn Inc
Tipo: Artigo de Revista Científica
Publicado em //2006 Português
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Background: The clinical technique for sandwich restorations prescribes etching initially set auto cure glass ionomer cement (GIC) prior to placing a layer of resin bond to develop a weak mechanical bond between composite resin and GIC. Co-curing a resin modified glass ionomer cement (RMGIC) bond and composite resin to GIC may create a chemical bond and improve the bond strengths between these two materials. Methods: A total of 48 specimens were prepared, 12 in each of four categories. Capsulated GIC was placed into a mould and allowed to set for four minutes, etched for five seconds followed by placement of a resin bond and photo cured for five seconds over which a composite resin was puddled onto the resin bond and photo cured for 10 seconds. Capsulated GIC was placed into a mould and allowed to set for four minutes after which a sample of RMGIC (Riva LC) was prepared using twice the liquid powder ratio and painted over the surface of the set GIC using a micro brush. An increment of composite resin was added over the RMGIC and both materials were photo co-cured for 10 seconds. Capsulated GIC was placed into a mould and RMGIC (Riva LC) that had been prepared using twice the liquid powder was brushed over the GIC (prior to initial set) followed by the placement of a layer of composite resin and photo co-cured for 10 seconds. Capsulated GIC was placed into a mould and RMGIC (Fuji II LC) that had been prepared using twice the liquid powder was brushed over the GIC (prior to initial set) followed by the placement of a layer of composite resin and photo co-cured for 10 seconds. Shear testing of each of the samples was carried out and specimens were examined to determine the nature of the fracture. Selected samples were prepared for SEM investigation to observe the interfaces between the GIC and composite resin. Results: There were significantly lower bond strengths (P<0.05) amongst samples that had been etched and bonded (2.42MPa) compared to the other samples that had been co-cure bonded with RMGIC (6.48–7.05MPa). There were no significantdifferences amongst the bond strengths of the samples co-cure bonded with RMGIC. Specimens prepared by the ‘etch and bond’ technique failed adhesively and co-cured specimens failed cohesively within the GIC. SEM investigation showed chemical bonds between RMGIC bond and GIC and composite resin. Conclusions: The co-cured RMGIC bonding system eliminates several placement steps and produces a significantly stronger chemical bond between GIC and composite resin than the ‘etch and bond’ technique. RMGIC bond and composite resin may be co-cured to GIC either before or after initial set has occurred.; The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.

Domestic Bond Market Development; The Arirang Bond Experience in Korea

Batten, Jonathan A.; Szilagyi, Peter G
Fonte: World Bank Publicador: World Bank
Tipo: Journal Article; Journal Article
Português
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36.57%
A two-tiered approach to financial market development aimed at both bank and bond market reform would also be complementary to longer term economic development, provided services could be delivered through efficient financial and legal institutions (Chakraborty and Ray 2006) and there was strong protection for investors and sound fiscal and monetary policy management by government (Burger and Warnock 2006b). Historically, local issuers tend to issue in the major currencies (U.S. dollars, yen, and euro), and then either swap the proceeds into local currency (interest rate parity theory suggests this should deliver funds equivalent in yield to what is available in the domestic market) or, more often, sell the foreign currency proceeds in spot foreign exchange markets, leaving the repayment cash flows unhedged. Chakraborty and Ray (2006) recently established that although stronger bank monitoring helps to resolve information asymmetries and agency concerns, it is the efficiency of financial and legal institutions that influences growth outcomes, whether there is a bank- or a market-based financial system. Among them are the need for enabling regulation, including reform of withholding and other foreign investor taxes (Lejot, Arner, and Liu 2006); continuing reform of corporate governance...

South Asian Bond Markets : Developing Long-Term Finance for Growth

Sophastienphong, Kiatchai; Mu, Yibin; Saporito, Carlotta
Fonte: Washington, DC : World Bank Publicador: Washington, DC : World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
Português
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36.61%
Bond markets play an essential part in economies. As part of a diversified financial system, a well-developed domestic bond market can help provide the long-term financing needed for sustainable growth. It can also produce broad-ranging benefits throughout the economy. In South Asia the development of domestic debt securities markets lags. The markets remain small compared both with the size of the region's economies and with markets in East Asia. Even in India the market is still small relative to Gross Domestic Product (GDP), suggesting that long-term debt financing remains at an early stage in the region. Equity markets and banks still dominate South Asian financial systems. Measures are needed to enhance both the depth and the breadth of South Asian bond markets, to bring them into line with those in East Asia and, in the long run, with those in Organization for Economic Co-operation and Development (OECD) countries. This study assesses domestic debt securities markets in South Asia, identifies constraints to their development...

Is There a Distress Risk Anomaly? Corporate Bond Spread as a Proxy for Default Risk

Anginer, Deniz; Yildizhan, Celim
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Publications & Research :: Policy Research Working Paper
Português
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Although financial theory suggests a positive relationship between default risk and equity returns, recent empirical papers find anomalously low returns for stocks with high probabilities of default. The authors show that returns to distressed stocks previously documented are really an amalgamation of anomalies associated with three stock characteristics -- leverage, volatility and profitability. In this paper they use a market based measure -- corporate credit spreads -- to proxy for default risk. Unlike previously used measures that proxy for a firm's real-world probability of default, credit spreads proxy for a risk-adjusted (or a risk-neutral) probability of default and thereby explicitly account for the systematic component of distress risk. The authors show that credit spreads predict corporate defaults better than previously used measures, such as, bond ratings, accounting variables and structural model parameters. They do not find default risk to be significantly priced in the cross-section of equity returns. There is also no evidence of firms with high default risk delivering anomalously low returns.