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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Resistência de união de sistemas adesivos autocondicionantes: efeito de diferentes tratamentos em substrato dentinário hipermineralizado artificialmente / Bond strength of self-etching adhesive systems: effect of different treatments on the artificially hipermineralized dentin

Possetti, Tamíris da Costa Neves [UNESP] 13 January 2017 (has links)
Submitted by TAMIRIS DA COSTA NEVES POSSETTI null (tamipcn@yahoo.com.br) on 2017-04-27T19:29:01Z No. of bitstreams: 1 DISSERTAÇÃO MESTRADO TAMÍRIS - REPOSITÓRIO UNESP.pdf: 2125002 bytes, checksum: 3813c634d79cc97db4ee8148198ce8e7 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-03T14:50:15Z (GMT) No. of bitstreams: 1 possetti_tcn_me_arafo.pdf: 2125002 bytes, checksum: 3813c634d79cc97db4ee8148198ce8e7 (MD5) / Made available in DSpace on 2017-05-03T14:50:15Z (GMT). No. of bitstreams: 1 possetti_tcn_me_arafo.pdf: 2125002 bytes, checksum: 3813c634d79cc97db4ee8148198ce8e7 (MD5) Previous issue date: 2017-01-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi avaliar a resistência de união imediata, de sistemas adesivos autocondicionantes, frente a diferentes tratamentos da superfície dentinária hipermineralizada artificialmente. Incisivos bovinos hígidos (N=80) foram preparados, incluídos em resina acrílica, hipermineralizados artificialmente e aleatoriamente distribuídos em dois grupos, de acordo com o sistema adesivo autocondicionante utilizado: Universal (3M ESPE; n=40); Optibond All in One (Kerr; n=40). Para cada sistema adesivo foram realizados cinco diferentes protocolos: (T1) sistema adesivo segundo recomendações do fabricante (n=8); (T2) ácido fosfórico 37% por 15” + sistema adesivo (n=8); (T3) laser Er,Cr:YSGG (Waterlaser Millenium, Biolaser Technology, San Clement, CA, USA) + sistema adesivo (n=8); (T4) ácido fosfórico 37% por 15” + laser Er,Cr:Y5GG + sistema adesivo (n=8); (T5) laser Er,Cr:YSGG + ácido fosfórico 37% por 15” + sistema adesivo (n=8). Após os procedimentos adesivos e restauradores, os dentes permaneceram em ambiente úmido, a 37ºC, por 24 horas, para posteriormente passarem pelo ensaio de microcisalhamento. Os resultados de resistência de união foram obtidos em MPa e submetidos à Análise de Variância e Teste de Tukey ao nível de significância de 5%. O padrão de fratura de cada espécime foi avaliado e observou-se um padrão de fratura predominantemente adesivo. Os resultados mostraram que, para o sistema adesivo Optibond All in One, o maior valor de resistência de união foi obtido no grupo T1, sendo que apenas o grupo T3 foi considerado estatisticamente semelhante à este. O menor valor de resistência de união para este material ocorreu em T5. Para o sistema adesivo Universal, todos os tratamentos foram estatisticamente semelhantes a T1, com exceção do grupo T2, que apresentou a menor média de resistência de união. / This study aims to evaluate the immediate bond strength of self-etching adhesive systems after different treatments of the artificially hypermineralized dentin. Bovine healthy incisors (n=80) were prepared, embedded in acrylic resin and randomly distributed into two groups according to the time of adhesive systems used: Group A - Universal (3M ESPE, n=40) and Group B - Optibond All in One (Kerr, n=40). For each adhesive system, five different protocols were performed: (T1) adhesive system according to the recommendations of the manufacturer (n=8); (T2) phosphoric acid conditioning 37 % for 15" + adhesive system (n=8); (T3) laser Er,Cr:YSGG (Waterlaser Millenium, Biolaser Technology, San Clemente, CA, USA) + adhesive system (n=8); (4) phosphoric acid conditioning 37% for 15" + laser Er,Cr:Y5GG + adhesive system (n=8); (T5) laser Er,Cr:YSGG + phosphoric acid conditioning 37% for 15" + adhesive system (n=8). After the bonding procedures and composite insertion, the specimens were maintained in a humid environment at 37ºC for 24 hours, and then submitted to the microshear bond strength test. The bond strength results were obtained in MPa and submitted to Variance Analysis and Tukey's Test at a significance level of 5%. The fracture pattern of each specimen was evaluated. The pattern fracture of each specimen was evaluated and a predominantly adhesive pattern was observed. The results showed that, for the Optibond All in One adhesive system, the highest union resistance value was obtained in the T1 group, and only the T3 group was considered statistically similar to this. The lowest union resistance value for this material occurred at T5 group. For the Universal adhesive system, all treatments were statistically similar to T1, except for group T2, which presented the lowest union resistance average.
102

Bond strength of a total-etch adhesive system with different viscosities to ER:YAG LASER irradiated dentin / ResistÃncia de uniÃo de um sistema adesivo de condicionamento total com diferentes viscosidades à dentina tratada com Laser de ER:YAG

Renato Queiroz Nogueira Lira 18 July 2013 (has links)
nÃo hà / Preparos cavitÃrios dentÃrios confeccionados com laser de Er:YAG podem resultar em uma maior conservaÃÃo de tecidos sadios, maior abertura dos tÃbulos dentinÃrios sem presenÃa de lama dentinÃria, menor nÃmero de microrganismos na cavidade, alÃm de menor sensibilidade dolorosa durante sua confecÃÃo. Considerando que a irradiaÃÃo a laser pode diminuir a resistÃncia de uniÃo de materiais restauradores à dentina, esse estudo analisou o efeito da viscosidade de um sistema adesivo de condicionamento total de dois passos, em dentina irradiada com laser de Er:YAG. A dentina preparada foi testada em 2 tipos de preparo de superfÃcie (ponta diamantada e laser de Er:YAG) e a viscosidade do adesivo em 3 diferentes diluiÃÃes (Adperâ Single Bond 2 [SB], SB+10% e SB+20% de etanol). Sessenta terceiros molares humanos foram cortados e polidos, expondo superfÃcies de dentina oclusal. Foi utilizado o sistema adesivo SB para preparar as formulaÃÃes com diferentes viscosidades. As superfÃcies de dentina foram condicionadas com Ãcido fosfÃrico e os adesivos foram aplicados de acordo com as instruÃÃes do fabricante. PlatÃs de resina composta (Filtekâ Z250 XT) de 5 mm foram confeccionados. Os dentes preparados foram estocados em Ãgua destilada (37ÂC) por 24 h. Os espÃcimes foram seccionados em palitos de cerca de 1 mm de Ãrea transversal, os quais foram submetidos ao teste de microtraÃÃo. Propriedades fÃsico-mecÃnicas como Ãngulo de contato, taxa de evaporaÃÃo, grau de conversÃo, sorÃÃo/solubilidade de Ãgua e viscosidade dos adesivos foram definidas. Todos os resultados foram analisados com Two-way ANOVA e teste de comparaÃÃes mÃltiplas de Tukey (α=0.05). NÃo houve diferenÃa estatÃstica entre os valores de microtraÃÃo para todos os grupos. Os nÃveis de viscosidade nÃo afetaram a resistÃncia de uniÃo da dentina irradiada com laser de Er:YAG ou tratada com ponta diamantada. / Dental cavities prepared with Er:YAG laser may result in greater conservation of sound tissue, further opening of dentinal tubules without the presence of smear layer, few microorganisms in the cavity, and lower pain sensitivity during operative procedure. Whereas laser irradiation may decrease the bond strength of resin materials to dentin, this study examined the effect of viscosity of a two-step total-etch adhesive system on the bonding to dentin irradiated with Er:YAG laser. The prepared dentin was tested in 2 types of surface preparation (diamond tip and Er:YAG laser) and the viscosity of the adhesive at 3 different dilutions (Adperâ Single Bond 2 [SB], SB+10% e SB+20% de ethanol). Sixty human third molars were sectioned and polished, exposing dentin occlusal surfaces. SB adhesive system was used to prepare formulations with different viscosities. The dentin surfaces were acid etched and the adhesives were applied according to the manufacturer's instructions. Composite resin buildups (Filtekâ Z250 XT) of 5 mm were made. Prepared teeth were stored in distilled water (37oC) for 24 h. Specimens were sectioned into sticks (1 mm of cross sectional area), which were submitted to microtensile test. Physical-mechanical properties, such as contact angle, evaporation rate, degree of conversion, sorption/solubility of water and viscosity of the adhesives were defined. All results were compared with Two-way ANOVA and Tukey multiple comparison test (α=0.05). There was no statistical difference between the values of microtensile for all groups. The viscosity levels did not affect the bond strength of dentin treated either with Er:YAG laser or diamond bur.
103

Nonlinear viscoelastic characterization of structural adhesives

Rochefort, M. A. January 1983 (has links)
Measurements of the nonlinear viscoelastic behavior of two adhesives, FM-73 and FM-300, are presented and discussed. Analytical methods to quantify the measurements are given and fitted into a framework of an accelerated testing and analysis procedure. The single integral model used is shown to function well and is analogous to a time-temperature stress-superposition procedure (TTSSP). Advantages and disadvantages of the method accessed with the latter residing primarily with the nature of the creep power law which is utilized. / M.S.
104

Water sorption and resin hydrophilicity of dentin bonding agents

Dhanpal, Prashanth Kumar. January 2007 (has links)
published_or_final_version / Dentistry / Master / Master of Dental Surgery
105

An interactive micromorphological study of resin infiltration into acid conditioned dentine

鄭智明, Tay, Franklin R. January 1997 (has links)
published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy
106

An in vitro study of microleakage and surface microhardness of nanocomposite restorative materials.

Majeed, Abdul January 2005 (has links)
The demand for posterior aesthetic restorations has dramatically increased in recent years. Several new materials have been developed with improved aesthetic, adhesive and mechanical properties. However, microleakage elimination, especially if the margins are on dentine or cementum, and attainment of optimum mechanical properties for posterior use, are still questionable. The aim of this study was to investigate microleakage and surface microhardness of a nanofilled, a nanohybrid and an ormocer based nano-ceramic composite restorative material.
107

The retentive strength of bonded amalgam restorations.

Banna Trinadha Rao January 2005 (has links)
<p>Amalgam bonding agents have been shown to enhance retention of amalgam restorations by mechanical means. However, recent studies showed that the use o glass ionomer cements and resin cements as lining and bonding materials to amalgam restorations will increase the retentive strength of the amalgam restorations, hence reducing the micro leakage and secondary caries. The purpose of this study was to compare the relative retentive strength of conventional amalgam restorations and bonded amalgam restorations using resin adhesive, glass ionomer cements and resin cements.</p>
108

The effect of dentine-bonding agents on the microleakage of provisional crowns.

Moosa, Rustim January 2005 (has links)
<p>The use of provisional acrylic crowns is common practice with prosthodontic treatment. Provisional crowns are prone to marginal leakage and poor retention due to weak interim cements. The aim of this study was to assess the effect of the application of two different dentine-bonding agents on the microleakage of provisional crowns.</p>
109

Adesivos estruturais uretânicos aplicados a combinações de compósitos, plásticos e metais / Structural urethane adhesives applied in combination of composites, plastics and metals

Quini, Josué Garcia 14 March 2011 (has links)
Neste trabalho foram avaliadas as propriedades de um adesivo estrutural uretânico que visavam colagens de peças automotivas compostas por combinações de compósitos, termoplásticos e metais, que requerem do adesivo um elevado desempenho e compatibilidade com esses materiais. Para tanto, foram avaliadas as resistências ao cisalhamento de juntas formadas com estes substratos e o adesivo uretânico em diversas condições de exposição, que visam simular os efeitos deletérios que estas juntas estarão expostas durante sua utilização. Estes métodos permitiram caracterizar o adesivo como estrutural para tais aplicações, pois em todos os ensaios a fratura se deu fora da área de colagem, levando a conclusão de que a junta formada é mais resistente do que o substrato isoladamente. Foram desenvolvidos dois inovadores tratamentos de superfície alternativos ao lixamento, que foram o desengraxe com solventes e tratamento com plasma. Estes tratamentos tem contribuído significativamente om a comunidade e a partir deste estudo tem sido utilizados na indústria. A avaliação do comportamento térmico do adesivo e dos substratos permitiu o desenvolvimento de métodos de análise da composição das frações de massa de matriz polimérica, cargas minerais e fibra de vidro de modo prático, rápido e preciso, por uso da termogravimetria. A calorimetria diferencial exploratória possibilitou avaliar as transições vítreas dos substratos e do adesivo, bem como a energia liberada na reação do adesivo uretânico. Os fenômenos de interação química entre o adesivo e os substratos foram investigados pelo uso da técnica de espectroscopia infravermelho por reflectância atenuada, onde pode-se de forma inédita comprovar a existência de reações covalentes e de hidrogênio entre o adesivo e os substratos, que explicam a elevada aderência deste adesivo.Os resultados de todos os ensaios e análises levam à conclusão final que o adesivo uretânico, embora muitas vezes não considerado como estrutural, é um candidato plenamente capacitado ao trabalho de adesão estrutural, especialmente para uso automotivo nas condições descritas neste trabalho. / In this study there were evaluated the properties of a structural urethane adhesive used for bonding automotive parts made from combinations of composites, thermoplastics and metals, which require a high adhesive performance and compatibility with these materials. Thus, there were evaluated the shear strength of joints formed with these substrates and adhesive urethane different exposure conditions, which aim to simulate the deleterious effects that these joints are exposed during their use. These methods allowed characterization like structural adhesive for these applications, because in all tests the fracture occurred outside the area of bonding, leading to the conclusion that the joint formed is stronger than the substrate alone. There were developed two innovative surface treatments alternative to grinding, which was a degreasing solvent and treatment with plasma. These methods have significantly contributed to the community and from this study has been used in industry. The evaluation of the thermal behavior of the adhesive and the substrates allowed the development of methods for analyzing the composition of mass fractions of polymer matrix, fillers and fiberglass in a practical, fast and accurate, by use of thermogravimetry. The differential scanning calorimetry allowed to evaluate the glass transitions of substrates and adhesive, and the energy released in the reaction of urethane adhesive. The phenomena of chemical interaction between the adhesive and the substrates were investigated by use of infrared spectroscopy by attenuated reflectance, where it can be in an unprecedented way to prove the existence of covalent and hydrogen reactions between the adhesive and the substrates, which explains the high adhesion of this adhesive.The results of all testing and analysis lead to the final conclusion that the adhesive urethane, although often not considered as structural, is a fully qualified candidate for structural work of adhesion, especially for automotive use under the conditions described in this thesis.
110

Improvement of adhesive strength between polymer and indium-tin oxide with self-assembly monolayers =: 利用自身組織單層分子薄膜改善聚合物和氧化銦錫導電膜之間的黏著力. / 利用自身組織單層分子薄膜改善聚合物和氧化銦錫導電膜之間的黏著力 / Improvement of adhesive strength between polymer and indium-tin oxide with self-assembly monolayers =: Li yong zi shen zu zhi dan ceng fen zi bo mo gai shan ju he wu he yang hua yin xi dao dian mo zhi jian de nian zhu li. / Li yong zi shen zu zhi dan ceng fen zi bo mo gai shan ju he wu he yang hua yin xi dao dian mo zhi jian de nian zhu li

January 2002 (has links)
by Sin Lai Yi, Mandy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 120-121). / Text in English; abstracts in English and Chinese. / by Sin Lai Yi, Mandy. / Abstract --- p.ii / 論文摘要 --- p.iii / Acknowledgements --- p.iv / Table of Contents --- p.v / List of Figures --- p.ix / List of Tables --- p.xiii / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Adhesion --- p.1 / Chapter 1.2 --- Adhesion issues in PLEDs --- p.1 / Chapter 1.3 --- Literature review of the adhesion measurement techniques --- p.4 / Chapter 1.3.1 --- Methods involving detachment normal to the interface --- p.4 / Chapter 1.3.1.1 --- Direct pull-off method --- p.5 / Chapter 1.3.2 --- Methods based upon the application of lateral stresses for detachment --- p.7 / Chapter 1.3.2.1 --- Scotch tape method --- p.7 / Chapter 1.3.2.2 --- Peel test --- p.8 / Chapter 1.4 --- Motivations and aims of studies --- p.11 / Chapter 1.5 --- Outline of the thesis --- p.12 / Chapter Chapter 2 --- Experimental and Instrumentation / Chapter 2.1 --- Sample preparation --- p.13 / Chapter 2.2 --- Instrumentation --- p.13 / Chapter 2.1.1 --- Modified Scotch tape method --- p.13 / Chapter 2.2.2 --- Atomic force microscope --- p.23 / Chapter 2.2.3 --- X-ray photoelectron spectroscopy --- p.26 / Chapter 2.2.4 --- Radio-frequency (RF) plasma etching system --- p.27 / Chapter Chapter 3 --- Verification of the modified Scotch tape method / Chapter 3.1 --- Introduction --- p.31 / Chapter 3.2 --- Verification Test One ´ؤ Measurement against different adhesive tapes --- p.31 / Chapter 3.3 --- Verification Test Two ´ؤ Measurement with different crosshead speeds --- p.40 / Chapter 3.4 --- Verification Test Three ´ؤ Measurement of adhesive tapes with different sizes --- p.46 / Chapter 3.5 --- Summary --- p.51 / Chapter Chapter 4 --- Adhesion of gold films coated on the plasma treated ITO / Chapter 4.1 --- Introduction --- p.53 / Chapter 4.2 --- Characteristics of RF plasma etching --- p.53 / Chapter 4.2.1 --- Test One ´ؤ Study the relationship between sputtering time and sputtering depth --- p.54 / Chapter 4.2.2 --- Test Two - Study the relationship beteen self-bias voltage and sputtering depth --- p.54 / Chapter 4.3 --- Modification of the surface morphology of the Ar plasma treated ITO --- p.57 / Chapter 4.4 --- Quantitative adhesion measurement of gold films on plasma treated ITO --- p.62 / Chapter 4.5 --- Summary --- p.68 / Chapter Chapter 5 --- Adhesion of PFO on ITO with self-assembled monolayers as interfacial layers / Chapter 5.1 --- Introduction --- p.69 / Chapter 5.2 --- Reactions between SAMs and ITO --- p.71 / Chapter 5.3 --- Sample preparation --- p.73 / Chapter 5.4 --- Tests of alkylsilane --- p.74 / Chapter 5.4.1 --- Determination of the point of film detachment --- p.74 / Chapter 5.4.2 --- Adhesion test of PFO/alkylsilane/ITO --- p.79 / Chapter 5.4.3 --- Adhesion test of PF0/alkylsilane/Si02 --- p.91 / Chapter 5.5 --- Tests of phenylsilane --- p.104 / Chapter 5.6 --- Summary --- p.114 / Chapter Chapter 6 --- Conclusions and further studies / Chapter 6.1 --- Conclusions --- p.116 / Chapter 6.2 --- Further studies --- p.118 / References --- p.120

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