Orientadores: Luiz Andre Freire Pimenta, Mario Alexandre Coelho Sinhoreti / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-12T16:36:14Z (GMT). No. of bitstreams: 1 Soeiro_CaioRaphaelMartins_D.pdf: 792390 bytes, checksum: 07f8d0fd2a9315402a13ccecf7098f0a (MD5) Previous issue date: 2008 / Resumo: A utilização de procedimentos adesivos está consolidada na odontologia atual, sendo protocolo indispensável à realização de uma ampla gama de procedimentos preventivos e restauradores. Os substratos dentais, esmalte e dentina, diferem quanto a sua composição, morfologia e, conseqüentemente, em relação à sua interação com os sistemas adesivos. A remoção do colágeno exposto pelo condicionamento ácido, procedimento também conhecido por desproteinização da dentina condicionada, é sugerido para remover alguns dos problemas enfrentados na união à dentina, como a degradação do colágeno e a incompleta infiltração do sistema adesivo. Além disso, a remoção da matéria orgânica poderia aumentar a energia livre de superfície da dentina condicionada, facilitando seu molhamento pelo sistema adesivo. O uso de hipoclorito de sódio, em concentração de 10%, apresentado em forma de solução ou gel, tem sido estudado na remoção das fibrilas colágenas dentinárias. O objetivo desta tese foi avaliar o comportamento de sistemas adesivos com diferentes solventes frente à desproteinização. Três estudos focam diferentes aspectos dessa união, tais como tempo de aplicação do sistema adesivo, tipo de solvente do agente de união, armazenagem a longo prazo em água a 37oC e ainda a avaliação da aplicação do hipoclorito sob a apresentação líquida ou em forma de gel. Os resultados mostram que a remoção do colágeno dentinário ainda se mostra muito heterogênea e dificilmente aplicável em procedimentos clínicos futuros visando o aumento dos valores de resistência de união dos sistemas adesivos ao substrato dentina. Estudos futuros necessitam ser realizados visando definir com clareza o real papel da remoção do colágeno na união adesiva dentinária. / Abstract: The use of adhesives systems is well-known at current dentistry. Most of prevent and restorative procedures requires an adhesive technique. The dental tissues, enamel and dentin, differ from its composition, morphology and, thus, their relation to adhesive systems available. The collagen removal after acid conditioning (dentin deproteinization), could remove some of troubles founded by adhesion between adhesives and dentin tissue, as collagen degradation and incomplete infiltration of adhesives systems thought demineralized dentin, as well an increase in wettability of those adhesives. The use of 10% sodium hypochlorite, as solution or gel, had been studied in its capacity to remove dentin collagen fibrils. The aim of this thesis was to evaluate the behavior of some adhesive systems applied in a demineralized and deproteinized dentin substrate. Three studies present different characteristics of this union: influence of adhesive application time, adhesive solvent type, storage of restored specimens in water at 37oC and a comparison of NaOCl efficacy used in a solution or gel form. According to the results, the dentin collagen removal is not completely effective in an increase of bond strength values, regardless adhesive system or technique applied. Further studies need to be done to disclose the hole of sodium hypochlorite in dentin bonding. / Doutorado / Dentística / Doutor em Clínica Odontológica

Orientador: Marcela Rocha de Oliveira Carrilho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T10:43:41Z (GMT). No. of bitstreams: 1 Malacarne-Zanon_Juliana_D.pdf: 9128347 bytes, checksum: 0fea8a055f819faabf3edb9b08ea04de (MD5) Previous issue date: 2009 / Resumo: Este estudo, composto por três trabalhos, avaliou o efeito de diferentes tipos e concentrações de solventes orgânicos no grau de conversão (DC) e na permeabilidade de diferentes sistemas adesivos. No primeiro estudo, o DC de cinco adesivos experimentais de composição hidrófila/hidrófoba conhecida (R1<R2<R3<R4<R5), contendo 5%p/p ou 15%p/p etanol, assim como a sorção (WS), a solubilidade (SL) e a cinética de difusão da água (D) nos polímeros obtidos foram mensurados. No segundo estudo, a WS, a SL e a nanoinfiltração de prata (NN) em adesivos experimentais (R2, R3 e R5), polimerizados na presença de 15%p/p etanol ou 15%p/p acetona, foram avaliados após 7 dias (7d) e 6 meses (6m) de armazenamento. No terceiro estudo, foi avaliada a NN em sete adesivos comerciais, formulados com diferentes tipos e concentrações de solventes, para serem aplicados ao substrato dental com diferente número de passos clínicos. Todos os espécimes foram confeccionados em matriz metálica (0,8mm x 5,8mm), aplicando-se 80s de fotoativação a 650mW/cm2. O DC foi determinado por espectroscopia de infra-vermelho. Para o cálculo de WS, SL e D, os espécimes foram tratados de acordo com as normas da ISO 4049, exceto para os tempos de aferição das massas úmidas, que foram obtidos sequencialmente durante os 7 primeiros dias de armazenagem em água e após 6 meses. Para avaliação da nanoinfiltração, os espécimes foram infiltrados com nitrato de prata amoniacal, conforme protocolo de nanoinfiltração (Tay et al., 2002), exceto pelo tempo que os espécimes permaneceram na solução de nitrato de prata (48 h). Em seguida, os mesmos foram preparados para observação em microscópio eletrônico de varredura. Os valores obtidos de DC, WS, SL e D foram submetidos à análise de variância e, em seguida, ao teste de Tukey (a=0,05). A presença de etanol aumentou o DC de todas as resinas avaliadas, especialmente as mais hidrófobas R1 e R2 (p<0,05). A WS, a SL e o D dos adesivos experimentais aumentaram com a hidrofilia. Em geral, as resinas contendo 15% de solvente exibiram maior WS, SL e D que suas correspondentes não-solvatadas ou contendo 5% de solvente (p<0,05). Não foram encontradas diferenças significativas entre os tipos de solventes presentes (p>0,05). Diferenças significativas entre os tempos de avaliação de WS, de SL e de NN, em geral, foram encontradas para os espécimes mais hidrófilos (p<0,05). Os componentes menos hidrófilos dos sistemas adesivos indicados para serem aplicados utilizando-se maior número de etapas clínicas mostraram menor NN que os sistemas adesivos "simplificados". Adesivos hidrófilos apresentaram diferentes permeabilidades em solução aquosa. Os mais hidrófilos, contendo maiores concentrações de solventes orgânicos, são mais permeáveis e, consequentemente, mais susceptíveis à degradação ao longo do tempo. / Abstract: This study evaluated the effect of different solvent types and concentrations on the degree of conversion (DC) and permeability of different adhesive systems. In the first study, the DC of five experimental adhesives of known hydrophilicity based on their solubility parameters (R1<R2<R3<R4<R5), added with 5 wt% or 15 wt% ethanol, were evaluated. Additionally, water sorption (WS), solubility (SL) and diffusion coefficient of water (D) through the polymerized materials were also assessed. In the second work, the WS, SL and nanoleakage (NN) in model adhesives (R2, R3 e R5), polymerized in the presence of 15 wt% ethanol or 15 wt% acetone, were evaluated after 7 days (7d) and 6 months (6m) of water storage. In the third work, it was assessed the NN in seven commercial adhesive systems, formulated with different solvent types and concentrations, to be applied on dentin under different clinical approaches. All specimens were produced on teflon molds (0.8mm X 5.8mm), with 80 s of photoactivation, under 650 mmW/cm2. The DC was determined by infra-red spectroscopy. For WS, SL and D evaluations, specimens were treated according to ISO 4049, except for the times of m2 measurements, which were collected successively during the first 7 days of storage in water, and, then, after 6 months. For NN, specimens were stored in silver nitrate solution, according to the protocol reported by Tay et al. (2002), and then prepared for scanning electron microscopy evaluation. Values of DC, WS, SL and D were analyzed by ANOVA and Tukey's test (a=0,05). Ethanol addition increased the DC of all tested resins, but specially of the most hydrophobic ones, R1 and R2 (p<0.05). Permeability increased with the hydrophilicity of resin blends. In general, solvated resins exhibited significantly higher permeability than their correspondent neat versions (p<0.05). The only exceptions were R1 and R5, the least and the most hydrophilic adhesives respectively. Both exhibited similar WS values for neat and solvated versions (p>0.05). There were no significant differences when compared both solvents (p>0.05). Differences in WS, SL and NN, attributable to different times of water storage, were found for neat and solvated versions of R5. NN in the less hydrophilic components of commercial adhesive systems, indicated to be applied on dentin under multiple steps, were less evident than that observed in "simplified" adhesives. Based on the limitation of this study, it was concluded that more hydrophilic and solvated adhesives are more permeable to fluids diffusion and more vulnerable to water degradation effects over time. / Doutorado / Doutor em Materiais Dentários

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / There is a general consensus that resin-dentin bonds created by contemporary hydrophilic dentin adhesives deteriorate over time. One way to predict how resin-dentin interface would behave over time is aging the specimens in vitro by immersion in different solutions. The objective of this study was to evaluate the effect of immersion in NaOCl solution on the bond interface created by different adhesive systems. For this, it was used 28 human third molars that had superficial dentin exposed and composite build-ups were built on its surface using one of those adhesives, etch-and-rinse: Scothbond Multi-purpose and Single Bond, or self-etch: Clearfil SE and Adper SE. Specimens were cut into nontrimming dentin-composite beams to microtensile testing. After a period of 24 h in distilled water, sticks from each tooth were divided equally into two groups: control or aged in 10% NaOCl for 1 h. Beams were pulled until failure at crosshead speed of 1 mm/min and bond strength was calculated. Fractured sticks were analyzed and classified in: mixed fracture, cohesive in dentin and cohesive in composite; and expressed in percentage. Data from ÂTBS test were statistically analyzed using Kruskal-Wallis and Games-Howell tests. For comparison between control and aging groups was used the Mann-Whitney test (&#945;=0.05). Two specimens from each adhesive were used to investigate the effect of NaOCl on the interfacial morphological characteristics. For that, specimens were cut in only one direction, dentin-resin discs were fixed in a glass-holder and ground with SiC papers under running water. Slices were treated by Massonâs trichrome acid staining technique to evidence collagen exposed zones and analyzed by optical microscopy. ÂTBS results showed that NaOCl solution significantly reduced bond strength comparing with the control groups for all adhesives tested. Scothbond MP (control: 39,95Â12,72; aged: 26,45Â9,90 MPa) showed the highest values and Adper SE (control: 13,21Â3,15; aged 4,95Â2,49) the lowest in both control and aging groups. Clearfil SE (control : 27,02Â6,84; aged: 16,17Â3,79) and Single Bond (control : 26,66Â8,35; aged: 11,77Â4,28) showed no difference in control groups, but after aging, Clearfil SE showed better results. Microscopic images analysis showed that NaOCl acts efficiently on degradation of collagen fibrils for all adhesive systems. Conclusion: Aging in 10% NaOCl solution reduces bond strength and modifies the interfacial morphological characteristics of the adhesive systems tested. / Hà um consenso geral de que a uniÃo resina-dentina criada pelos adesivos dentinÃrios hidrofÃlicos contemporÃneos se deterioram com o tempo. Uma maneira de prever o comportamento da interface adesiva ao longo do tempo à atravÃs do envelhecimento in vitro por imersÃo em diferentes soluÃÃes. O objetivo deste trabalho foi avaliar o efeito da imersÃo em soluÃÃo de NaOCl na interface de uniÃo criada por diferentes sistemas adesivos. Para isso, foram usados 28 terceiros molares humanos que tiveram a dentina coronÃria exposta e um platà de resina composta confeccionado sobre sua superfÃcie apÃs a aplicaÃÃo de um dos seguintes sistemas adesivos, condicionamento total: Scothbond Multi-uso e Single Bond, ou autocondicionantes: Clearfil SE e Adper SE. Os espÃcimes foram cortados pela tÃcnica nontrimming de obtenÃÃo de palitos para o teste de microtraÃÃo. ApÃs um perÃodo de 24 horas em Ãgua destilada, os palitos de cada dente foram igualmente divididos em dois grupos: controle ou envelhecido em soluÃÃo de NaOCl a 10% por 1 hora. Os espÃcimes foram tracionados atà a ruptura da uniÃo a uma velocidade de 1 mm/min e sua forÃa de uniÃo mensurada. Os palitos fraturados foram analisados e classificados em: fratura mista, coesiva em dentina e coesiva em compÃsito, e os valores expressos em porcentagem. Os dados da resistÃncia de uniÃo foram estatisticamente analisados usando os testes Kruskal-Wallis e Games-Howell. Para comparaÃÃo entre os grupos controle e envelhecido foi usado o teste de Mann-Whitney (&#945;=0.05). Dois espÃcimes de cada adesivo foram usados para investigar o efeito do NaOCl nas caracterÃsticas morfolÃgicas da interface de uniÃo. Para isso, espÃcimes foram cortados ao longo eixo em apenas uma direÃÃo e os discos de dentina-resina foram fixados em lÃmina de vidro e desgastados com lixas de SiC sob refrigeraÃÃo com Ãgua. As lÃminas foram tratadas pela tÃcnica de coloraÃÃo Ãcida de Masson para evidenciar as zonas de colÃgeno exposto e observadas atravÃs de microscopia Ãptica. Os resultados do teste de microtraÃÃo mostraram que a soluÃÃo de NaOCl reduziu significativamente a forÃa de uniÃo em comparaÃÃo aos grupos controle para todos os adesivos testados. Scothbond MU (controle: 39,95Â12,72; envelhecido: 26,45Â9,90 MPa) mostrou os maiores valores de uniÃo e Adper SE (controle: 13,21Â3,15; envelhecido 4,95Â2,49) os menores valores, tanto para o grupo controle quanto envelhecido. Clearfil SE (controle: 27,02Â6,84; envelhecido: 16,17Â3,79) e Single Bond (controle: 26,66Â8,35; envelhecido: 11,77Â4,28) nÃo mostraram diferenÃa estatÃstica nos grupos controle, mas apÃs envelhecimento, Clearfil SE mostrou melhores resultados. A anÃlise das imagens microscÃpicas mostrou que o NaOCl agiu efetivamente na degradaÃÃo das fibras de colÃgeno para todos os sistemas adesivos testados. ConclusÃo: O envelhecimento dos espÃcimes em soluÃÃo de NaOCl a 10% reduziu a resistÃncia de uniÃo e modificou as caracterÃsticas morfolÃgicas da interface adesiva para os sistemas adesivos testados.

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.

Magister Chirurgiae Dentium (MChD) / 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. / South Africa

Magister Scientiae Dentium - MSc(Dent) / The objectives of this study were to create an in vitro situation which closest resembled the clinical situation by inclusion of human dentine discs at a specified anatomic location as barrier and evaluating if comparable or graded perfusion could be identified as well as whether a link existed between dentine thickness and permeability. The other leg of the study was to evaluate the cytotoxicity of Xeno III, one of the newly released new generation dentine bonding agents and to evaluate its cytotoxicity in an in vitro pulp chamber device, determining which thickness of dentine would be able to protect the dental pulp from noxious substances in the bonding agent. / South Africa

The use of Fibre Reinforced Polymers (FRP) has grown in popularity in the construction industry. FRP has proven useful in the retrofit of various types of structural elements. It may be used for the strengthening of beams, the seismic upgrade of walls panels, as well as the jacketing of columns to provide confinement. There exist several methods of FRP application for the case of structural retrofits. These include the application of pre-prepared FRP mats, or application of FRP via the wet lay-up process. However, a new technique developed at the University of British Columbia allows for the application of FRP in the form of a spray. Externally bonded Sprayed FRP (SFRP) is known to increase strength and energy absorption capacity of a retrofitted member as well as, or better than, FRP sheets. However, tests have primarily been carried out on concrete members only. An area of interest, into which not much research has been conducted, is the application of SFRP to timber. Timber bridges are extensively used in many parts of the world. Often due to remoteness and practical constraints, it is impossible to apply FRP sheets to retrofit these bridges. SFRP would be a much easier method of FRP application. This study looked at the application of SFRP to Douglas Fir (D.Fir) Beam specimens subjected to 3-Point Flexural Loading only. The specimens were treated with either a water based (Borocol) or oil borne (Creosote) antifungal preservative prior to being sprayed with FRP. Different combinations of adhesives/bonding agents including Hydroxymethylated Resorcinol and Polymeric Isocyanates were used to try to develop a strong bond. When considering using only chemical adhesives to obtain a proper bond between the two constituents of the composite, use of HMR is recommended for timber which is untreated or has been treated with a water borne preservative such as Borocol, while a pMDI adhesive such as AtPrime 2 is recommended for timber treated with an oil borne preservative such as Creosote. For Non Creosoted beams, adhesives did not generate as significant of a strength gain. For Creosoted beams, adhesives may be sufficient to generate significant strength gain when SFRP is applied to a beam. Considering that most structures in use would probably have been treated with a preservative similar to Creosote, in practice, AtPrime 2 or some other some sort of pMDI would probably be the adhesive of choice. Based on the results of the study, it is possible to say that the application of SFRP to retrofit/rehabilitate timber structures shows considerable promise. If a decent bond is achieved between the composite constituents, it is possible to substantially increase the ultimate flexural strength of the member, as well as drastically increase its ductility and energy absorption capacity. It is recommended that further tests be carried out using different types of loading schemes, geometrical configurations of SFRP, other types of anchorage, and development of a proper analytical model before the method is adopted for widespread use. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

The potential for conjugated linoleic acid (CLA) incorporation into pressure-sensitive adhesive (PSA) formulations was evaluated. A series of free radical bulk copolymerizations of CLA/styrene (Sty) and CLA/butyl acrylate (BA) were designed to allow the estimation of reactivity ratios. Bulk terpolymerizations of CLA/Sty/BA were also evaluated before moving to emulsion terpolymerizations of CLA/Sty/BA. The polymers were characterized for composition, conversion, molecular weight and glass transition temperature while latexes were characterized for viscosity, particle size, tack, peel strength, and shear strength. All experiments were performed at 80oC and monitored with attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. While bulk experiments were monitored off-line, the emulsion experiments were monitored in-line. Absorbance peaks related to the monomers and polymer were tracked to provide conversion and polymer composition data using a multivariate calibration method. Off-line measurements using gravimetry and 1H-NMR spectroscopy were compared to the ATR-FTIR data and no significant differences were detected between the measurement methods. Pseudo-kinetic models, developed and validated with the copolymer experimental data, were used to estimate reactivity ratios. The copolymer pseudo-kinetic models were extended to a terpolymer pseudo-kinetic model and validated with experimental data. The pseudo-kinetic models incorporated the ability of oleic acid, a common impurity found in CLA, to trap electrons thus influencing the reaction kinetics significantly. The influence of terpolymer composition, chain transfer agent concentration, cross-linker concentration, molecular weight, viscosity and particle size on tack, peel strength and shear strength was investigated by using a constrained mixture design. The final forms of the resulting empirical models allowed the creation of 3D response surfaces for PSA performance optimization. The incorporation of 30 wt.% CLA into a practical PSA application suitable for the removable adhesives category was achieved.

Please read the abstract in the section 00front of this document / Dissertation (MChD (Orthodontics))--University of Pretoria, 2007. / Orthodontics / unrestricted

Magister Scientiae Dentium - MSc(Dent) / 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. / South Africa