No description available.

No description available.

Master thesis deals with highly filled particulate composite materials for dental applications. In the practical part, the dimetacrylate matrix was filled with a mixture of particles of different types and different sizes to achieve the maximum possible packing. Moreover, filler content and the influence of filler on composite material was studied. Hydrolytic stability was also tested on composite materials. The methods used to characterize composite materials were bending test, thermogravimetric analysis (TGA), differential scanning photocalorimetry (DPC), dynamic-mechanical analysis (DMA) and scanning electron microscopy (SEM). Curing of the matrix was characterized by the degree of conversion, the heat of polymerization and the polymerization rate. Furthermore the polymerization shrinkage was measured. The glass transition temperature, the dynamic modulus at 40 °C and 100 °C, the modulus of elasticity, the strength, the critical value of the stress factor and the critical energy release rate were found in the tested samples.

Orientador: Mario Fernando de Goes / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-07-23T01:41:39Z (GMT). No. of bitstreams: 1 Pacheco_JoaoFelipeMota_D.pdf: 4282811 bytes, checksum: 41703a5d88ddb80855223eb94057a90b (MD5) Previous issue date: 1997 / Resumo: O objetivo deste estudo foi avaliar a influência de diferentes tratamentos na superfície do polímero de vidro Artglass (HERAEUS, Kulzer - Germany). Foi verificado também o efeito do agente de silanização (Porcelain Primer - BISCO, lnc. ltasca IL), do ativador superficial de compósitos (Composite Activator BISCO, lnc. ltasca IL) e do líquido para reparos do sistema Artglass na resistência à tração com o sistema adesivo All Bond 2 (BISCO, lnc. ltasca IL) associado ao cimento Choice Porcelain Venner System (BISCO, lnc. ltasca IL). Foram confeccionadas duzentos e quarenta amostras e divididas em 12 grupos com 20 amostras cada. Cada grupo foi submetido aos seguintes tratamentos: grupo 1 - jateamento com óxido de alumínio; grupo 2 - jateamento com óxido de alumínio e aplicação do Porcelain Primer; grupo 3 jateamento com óxido de alumínio e aplicação do Composite Activator; grupo 4 - jateamento com óxido de alumínio e aplicação do Artglass Liquid; grupo 5 - condicionamento com ácido fosfórico; grupo 6 - condicionamento com ácido fosfórico e aplicação do Porcelain Primer; grupo 7 - condicionamento com ácido fosfórico e aplicação do Composite Activator; grupo 8 condicionamento com ácido fosfórico e aplicação do Artglass Liquid; grupo 9 - condicionamento com ácido fluorídrico; grupo 10 - condicionamento COIIJ ácido fluorídrico e aplicação do Porcelain Primer; grupo 11 - condicionamento com ácido fluorídrico e aplicação do Composite Activator; grupo 12 - condicionamento com ácido fluorídrico e aplicação do Artglass Liquid. Após o tratamento, as amostras foram unidas em pares com auxílio do sistema adesivo e do cimento resinoso manipulados de acordo com as instruções do fabricante. Em seguida, os corpos-de-prova foram armazenados a 37 'GRAUS'C com umidade relativa do ar em 100%, durante 24 horas e, logo após, foram submetidos a 500 ciclos térmicos ajustados às temperaturas de 5'GRAUS'C, 37°C e 60°C, com duração de 30 segundos cada. Decorrido o período de 48 horas, os corpos-de-prova foram submetidos ao ensaio de tração em uma máquina de ensaio universal (Otto Wolpert Werke, Germany), a uma velocidade de 6 mm/minuto. As médias dos resultados obtidos foram: grupo 1 - 11,46 MPa; grupo 2 - 12,28 MPa; grupo 3 - 9,45 MPa, grupo 4 - 11,53 MPa; grupo 5 - 3,83 MPa; grupo 6 - 4,84 MPa; grupo 7 - 3,94 MPa; grupo 8 - 5,67 MPa; grupo 9 - 6,51 MPa; grupo 10 - 6,36 MPa; grupo 11 - 7,86 MPa; grupo 12 - 8,34 MPa. A seguir os resultados foram submetidos análise de variância e ao Teste de Tukey. Após os testes de resistência à tração as amostras foram examinadas em lupa estereoscópica com aumento de 16 vezes, onde foi verificado predomínio de fraturas coesivas do polímero de vidro para os grupos tratados com jateamento com óxido de alumínio. O efeito dos tratamentos de superfície foi analisado com auxílio de um microscópio eletrônico de varredura (Zeiss DSM 960, Germany). Os resultados indicaram que o maior valor de resistência de união foi obtido através do jateamento com óxido de alumínio associado ao agente de silanização. Nos demais grupos onde também foi realizado o jateamento com óxido de alumínio os valores de resistência de união foram superiores e diferentes estatisticamente, quando comparados aos outros grupos, com exceção da associação do ácido fluorídrico com o Composite Activator, que não diferiu do grupo 3. A análise através de M.E.V. das superfícies tratadas demonstrou um padrão morfológico mais favorável ao imbricamento micromecânico produzido com o jateamento com óxido de alumínio / Abstract: The purpose of this study was to evaluate the influence of different superficial treatment of glass polymeric material Artglass (Heraeus, Kulzer). The effect of the silane agent application (Porcelain Primer - Bisco, lnc., ltasca, IL), a superficial Composite activator mixture (Composite Activator - Disco, Inc., ltasca, lL) and also the Artglass Liquid was verified in the tensile strength with adhesive system AllBond 2 (Bisco, lnc., !tasca, lL) associated with the resin cement Choice Porcelain Venner System (Bisco, lnc., !tasca, IL). Two hundred and torty samples were made and divided into 12 groups. Each group contained 20 samples submitted to treatments: Group 1 sandblasting with aluminum oxide; Group 2 - sandblasting with aluminum oxide and Porcelain Primer application; Group 3 - sandblasting with aluminum oxide and Composite Activator application; Group 4 - sandblasting with aluminum oxide and Artglass liquid application; Group 5 - acid etching with phosphoric acid; Group 6 - acid etching with phosphoric acid and Porcelain Primer application; Group 7 - acid etching with phosphoric acid and Composite Activator application; Group 8 acid etching with phosphoric acid and Artglass Liquid application; Group 9 acid etching with hydrofluoridric acid; Group 10 - acid etching with hydrofluoridric acid and Porcelain Primer application; Group 11 - acid etching with hydrotluoridric acid and Composite Activator application; Group 12 - acid etching with. hydrofluoridric acid and Artglass Liquid application. Following the treatment, the samples were bonded into pairs with the adhesive system and the resin cement, applied according with the manufacturer's instructions. Then, the samples were stored in 37° with a relative humidity of 100% during 24 hours. Submitted into 500 thermal circles, adjusted to 5 'DEGREE'C, 37 'DEGREE'C and 60'DEGREE'C, lasting 30 second each. After 48 hours, the samples were submitted to a tensile strength test in a Universal test machine (Otto Wolpert Werke, Germany) with a crosshead speed 6 mm / minute. The average results were : Group 1 - 11,46 MPa; Group 2 - 12,28 MPa; Group 3 - 9,45 MPa; Group 4 - 11,53 MPa; Group 5 - 3,83 MPa; Group 6 - 4,84 MPa; Group 7 - 3.94 MPa; Group 8 - 5,67 MPA; Group 9 - 6,51 MPA; Group 10 6,36 MPa; Group 11 - 7,86 MPa; Group 12 - 8,34 MPa. ThereFore, the results were submitted to Anova and Tukey Test. Then the samples were examined in a stereoscopic magnifying glass (x16), where it was verified the prevailing of cohesive rupture of the Glass Polymer in the groups treated with aluminum oxide sandblasting. The efFect of the superficial treatments was analyzed by a Scanning Electron Microscopy. The results indicated that sandblasting with aluminum oxide associated with the silane agent attained the biggest value of the bond strength. ln groups where the aluminum oxide sandblasting was performed the values presented were higher and statistically significant comparing with the others groups, except the association between hydrotluoridric acid and Composite Activator, which did not differ from group 3. The analysis of the treated surface was made using the Scanning Electron Microscopy and showed a more suitable morphologic pattem to the micromechanic retention produced with aluminum oxide sandblasting / Doutorado / Doutor em Materiais Dentários

O objetivo no presente trabalho foi avaliar a fidelidade dimensional de troqueis de gesso tipo IV (Vel-Mix®), obtidos a partir de moldes de um único elastômero (Impregum® F), utilizando-se duas diferentes técnicas de moldagem (com casquete ou com moldeira de estoque). A fidelidade de cada troquel obtido foi avaliada através de uma coroa-padrão, a qual encaixava-se com alta precisão ao troquelpadrão, o qual era a estrutura original a ser moldada. Assim foram compostos os 4 seguintes grupos, com o aquecimento do molde não tendo sido efetuado apenas no primeiro deles: 1- do casquete de resina, sem contato com a porção cervical do troquel-padrão (Cstsa); 2- do casquete, também sem o referido contato (Cstca) ; 3- novamente do casquete, agora com contato (Cctca) e 4-. da moldeira de estoque perfurada (Mca). Com base nos resultados encontrados nas condições estabelecidas, após o respectivo tratamento estatístico, foi possível concluir que: 1 - o pior desempenho ocorreu com a moldeira perfurada, com um desajuste médio da ordem de 397, 70 micrometros; 2 - o casquete com toque e com aquecimento (desajuste médio de 85,37 micrometros) apresentou desempenho semelhante ao do casquete sem toque e sem aquecimento (desajuste médio de 102,38 micrometros) e 3 - o melhor desempenho ocorreu com o casquete sem toque e com aquecimento, com um desajuste médio de 0, 03 micrometros. / The aim in this study was to evaluate the dimensional accuracy of dies made with a type IV stone (Vel-Mix®) dies, obtained from moulds of a sole elastomer (Impregum® F), by employing 2 different moulding techniques, with a shell or with a perforated stock tray. Stone dies accuracy was measured by means of a standard crown which could be accurately fitted to the standard die, the original structure to be moulded. In this way, the following 4 groups were stablished, with the mould heating not being done only in the first of them: 1- with the acrylic resin shell cervically not contacting the standard die; 2- with the refered shell but without that contact; 3- once more with the shell, again with that contact and 3- with the stock tray. Under the stablished conditions, after statistical treatment of results, the following conclusions could be drawn: 1- worst performance was presented by the stock tray, with a 397,70 µm mean inaccuracy; 2- the shell performance with cervical contact and heated (85,37 µm mean inaccuracy) was similar to that of it without contact and without heating (102,38 µm mean inaccuracy) and 3- better performance was presented by shell without contact and with heating, with a 0,03 µm mean inaccuracy.

Objectives: This retrospective cohort study aimed to assess the survival time and factors associated with survival of anterior composite-resin restoration placed at the University of Iowa, College of Dentistry (UICOD). Methods: Patients at the UICOD who had anterior composite restorations placed between 1995-1997 and could be followed through 2013 were included in this study. Factors included: patient age and gender, tooth type (central or lateral incisor, or canine) and location (maxillary or mandibular), restoration size (1, 2, 3, 4 and more surfaces), provider type (dental student, graduate student, faculty), and clinic (operative, family, or other clinics) where the initial restoration placed. Survival time of a restoration was defined as how long a restoration lasted from the day of placement until the day of subsequent treatment. Subsequent treatment included: restorations, veneer and/or crowns, root canal therapy, and extraction. One restoration per patient was used for the study. Statistical analyses consisted of the Kaplan-Meier analysis and Cox regression (alpha=0.05). Results: Of the 668 subjects (mean±SD age=55±13 years and 60.8% females) who fulfilled the inclusion criteria, the mean±SD survival time of composite resin restoration was 11±7 years and an overall survival rate was 43.3%. Patients' gender, age, tooth location, and clinic type were not significantly associated with the survival time of composite resin restoration. Cox regression model indicated that significant differences in the restoration hazards were found on tooth type (p=0.002), provider type (p=0.003) and restoration sizes (p=0.0072). Central (HR=1.59; CI=1.23-2.07) and lateral (HR=1.36; CI=1.03-1.79) incisors had a significantly higher hazard ratio (HR) than canines, and faculty had significantly lower HR than undergraduate students (HR=0.68, CI=0.55-0.85). Restorations sizes one surface (HR=0.6; CI=0.44-0.81) and two surfaces (HR=0.65; CI=0.48-0.88) had significantly lower HR than four and more surfaces restorations. Conclusion: The mean and median survival time of anterior composite restoration at UICOD was 11 and 13 years, respectively. Tooth type, provider type, and restoration size were significant predictors for the survival time of anterior composite-resin restoration.

Made available in DSpace on 2014-06-11T19:27:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2004Bitstream added on 2014-06-13T19:35:57Z : No. of bitstreams: 1 silva_kg_me_araca.pdf: 3519498 bytes, checksum: 8be3bbadc0092628ca71b9618deb19ae (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Bisco Inc., Il, Usa / O objetivo deste estudo foi avaliar o efeito da variação do pH da solução desmineralizante em modelo de ciclagem de pH na dureza de superfície, liberação de flúor e característica de superfície dos materiais restauradores: Ketac-Fil Plus, Vitremer, Fuji II LC, Freedom e Fluorofil. Foram confeccionados, para cada material, 34 corpos-de-prova que tiveram a dureza de superfície inicial (DSI) determinada após a confecção. A seguir, foram divididos em 5 grupos (n=30) de acordo com a variação de pH (4,3; 4,6; 5,0; 5,5 e 6,2) da solução desmineralizante e submetidos a períodos cíclicos em solução desmineralizante (Des-6 horas) e remineralizante (Re-18 horas) por 15 dias. Decorrido este período, verificou-se a dureza de superfície final (DSF) e a característica de superfície (n=24). As soluções armazenadas diariamente foram utilizadas para a determinação da concentração de flúor (Des+Re). As variáveis DSI, DSF e alteração de dureza de superfície (% ADS) foram submetidas à análise de variância e a liberação de flúor ao teste de Kruskal-Wallis (p<0,05). A variação do pH proporcionou relação direta quando se comparou a dureza e inversa para a liberação de flúor nos cimentos de ionômero de vidro. Para as resinas compostas modificadas por poliácidos foi verificada relação inversa para a liberação de flúor, não havendo correlação na dureza. A característica de superfície foi influenciada pela variação do pH, ficando mais evidente nos menores pHs, exceto para as resinas compostas modificadas por poliácidos. Baseados nos resultados, concluiu-se que a variação do pH da solução desmineralizante do modelo de ciclagem influenciou a liberação de flúor dos materiais testados. Essa variação alterou a dureza e a característica de superfície dos cimentos de ionômero de vidro, mas não das resinas compostas modificadas por poliácidos. / The aim of this study was to evaluate the effect of pH of the demineralizing solution in a cycling model on surface hardness, fluoride release and surface aspects of restorative materials (Ketac-Fil Plus, Vitremer, Fuji II LC, Freedom and Fluorofil). Thirty-four specimens of each material were made and surface hardness was measured. Then, the specimens were randomized in five groups (n=30), according to pH (4.3; 4.6; 5.0; 5.5; and 6.2) of the demineralizing solution and submitted to a cycling model during 15 days. The specimens remained in the demineralizing solution for 6 hours and in the remineralizing solution for 18 hours. After that, surface hardness was measured again and surface aspects were observed (n=24). Fluoride concentration was determined daily in all solutions (De+Re). Data from SMH (before and after pH-cycling) and %SMHC were analyzed by analysis of variance (p<0.05); Kruskal-Wallis test was carried out for the results of fluoride release. For glass ionomer cements, the variation of pH led to a direct relationship when hardness was compared and to an inverse relationship with regards to fluoride release. For polyacid-modified resin composites, an inverse relationship was found regarding fluoride release; no correlation was observed with regards to hardness. Surface aspect was influenced by pH variation: an acidic pH led to a greater alteration, except for polyacid-modified resin composites. It was possible to conclude that pH of the demineralizing solution did influence fluoride release from the tested materials. The pH variation altered hardness and surface aspects of glass ionomer cements, but it did not influence polyacid-modified resin composites in those analysis.

O objetivo no presente trabalho foi avaliar a fidelidade dimensional de troqueis de gesso tipo IV (Vel-Mix®), obtidos a partir de moldes de um único elastômero (Impregum® F), utilizando-se duas diferentes técnicas de moldagem (com casquete ou com moldeira de estoque). A fidelidade de cada troquel obtido foi avaliada através de uma coroa-padrão, a qual encaixava-se com alta precisão ao troquelpadrão, o qual era a estrutura original a ser moldada. Assim foram compostos os 4 seguintes grupos, com o aquecimento do molde não tendo sido efetuado apenas no primeiro deles: 1- do casquete de resina, sem contato com a porção cervical do troquel-padrão (Cstsa); 2- do casquete, também sem o referido contato (Cstca) ; 3- novamente do casquete, agora com contato (Cctca) e 4-. da moldeira de estoque perfurada (Mca). Com base nos resultados encontrados nas condições estabelecidas, após o respectivo tratamento estatístico, foi possível concluir que: 1 - o pior desempenho ocorreu com a moldeira perfurada, com um desajuste médio da ordem de 397, 70 micrometros; 2 - o casquete com toque e com aquecimento (desajuste médio de 85,37 micrometros) apresentou desempenho semelhante ao do casquete sem toque e sem aquecimento (desajuste médio de 102,38 micrometros) e 3 - o melhor desempenho ocorreu com o casquete sem toque e com aquecimento, com um desajuste médio de 0, 03 micrometros. / The aim in this study was to evaluate the dimensional accuracy of dies made with a type IV stone (Vel-Mix®) dies, obtained from moulds of a sole elastomer (Impregum® F), by employing 2 different moulding techniques, with a shell or with a perforated stock tray. Stone dies accuracy was measured by means of a standard crown which could be accurately fitted to the standard die, the original structure to be moulded. In this way, the following 4 groups were stablished, with the mould heating not being done only in the first of them: 1- with the acrylic resin shell cervically not contacting the standard die; 2- with the refered shell but without that contact; 3- once more with the shell, again with that contact and 3- with the stock tray. Under the stablished conditions, after statistical treatment of results, the following conclusions could be drawn: 1- worst performance was presented by the stock tray, with a 397,70 µm mean inaccuracy; 2- the shell performance with cervical contact and heated (85,37 µm mean inaccuracy) was similar to that of it without contact and without heating (102,38 µm mean inaccuracy) and 3- better performance was presented by shell without contact and with heating, with a 0,03 µm mean inaccuracy.

Indiana University-Purdue University Indianapolis (IUPUI) / The furanone derivatives and their constructed polymers were synthesized, characterized and formulated into dental glass-ionomer cement (GIC) and resin composite for improved antibacterial properties. Compressive strength (CS) and S. mutans viability were used to evaluate the mechanical strength and antibacterial activity of the restoratives. Fuji II LC cement and P60 were used as control. The specimens were conditioned in distilled water at 37 oC for 24 h prior to testing. The effects of loading, saliva and aging on CS and S. mutans viability were investigated. The antibacterial effect of the furanone derivative on other bacteria was also studied. Chapter 2 describes how we studied and evaluated the formulated antibacterial glass-ionomer cement by incorporating the synthesized furanone derivative-containing polymer into the formulation. The results show that all the formulated furanone-containing cements showed a significant antibacterial activity, accompanying with an initial CS reduction. Increasing loading significantly enhanced antibacterial activity but reduced the initial CS of the formed cements. The derivative showed a broad antibacterial spectrum on bacteria including S. mutans, lactobacillus, S. aureus and S. epidermidis. Human saliva did not affect the antibacterial activity of the cement. The long-term aging study indicates that the cements may have a long-lasting antibacterial function. Chapter 3 describes how we studied and evaluated the formulated antibacterial resin composite by incorporating the synthesized furanone derivative into the basic resin formulations. The results show that the modified resin composites showed a significant antibacterial activity without substantially decreasing the mechanical strengths. With 5 to 30% addition of the furanone derivative, the composite kept its original CS unchanged but showed a significant antibacterial activity with a 16-68% reduction in the S. mutans viability. Further, the antibacterial function of the new composite was not affected by human saliva. The aging study indicates that the composite may have a long-lasting antibacterial function. In summary, we have developed a novel furanone-containing antibacterial system for dental restoratives. Both glass-ionomer cement and resin composite have demonstrated significant antibacterial activities. The modified experimental glass-ionomer cement is a promising system because the reduced strength of the cement with addition of the furanone-containing polymer is still above those demonstrated by original commercial cement Fuji II LC. The modified resin composite shows nearly no reduction in mechanical strength after incorporation of the antibacterial furanone derivative. It appears that both experimental cement and resin composite are clinically attractive dental restoratives that can be potentially used for long-lasting restorations due to their high mechanical strength and permanent antibacterial function.

The glass-ceramics containing apatite [Ca10(PO4)6(O,F2)] and wollastonite [CaO&amp / #8226 / SiO2] crystals as the predominant crystalline phases, (A-W glass-ceramics) were produced through controlled crystallization of the glasses in the MgO-CaO-SiO2-P2O5-F system. Phases formed in the crystallized counterpart of the glasses were identified by powder X-ray diffraction (XRD) analysis. The crystal morphology of the resultant glass-ceramics was examined using a scanning electron microscope (SEM). The crystallization kinetic parameters consisting of the activation energy for crystallization, (E), the Avrami parameter, (n), and frequency factor of the glass were determined with regard to small amount of TiO2 additions using non-isothermal differential thermal analysis (DTA). The values for E and n for apatite and wollastonite were 460 kJ/mol and 433 kJ/mol, and 3.1&plusmn / 0.1 and 1.5&plusmn / 0.1, respectively. When 4 wt% TiO2 was incorporated into the base glass, the values for E decreased to 408 and 320 kJ/mol for apatite and wollastonite, respectively / but the values for n increased from 3.1&plusmn / 0.1 to 3.3&plusmn / 0.1, and from 1.5&plusmn / 0.1 to 1.9&plusmn / 0.1 for apatite and wollastonite, respectively. TiO2 is an effective nucleating agent in this glass system for promoting the precipitation of both apatite and wollastonite crystals. Structure oriented changes in the indentation microhardness and tribological properties of the A-W glass-ceramics were evidenced. The microhardness at the free surface was 650&plusmn / 12 HV, but decreased with increasing depth distance from the free surface and attained 520&plusmn / 8 HV at a distance 0.5 mm below the free surface. The wear rate at the free surface was 0.7&plusmn / 0.05 &times / 10-4 mm3/Nm, but increased as the distance from the free surface increased and became 2.9&plusmn / 0.15 &times / 10-4 mm3/Nm at a distance 0.5 mm below the free surface. Tribological properties of the A-W glass-ceramics were compared with those of commercially available dental ceramics including IPS Empress 2&reg / , Cergo Pressable Ceramic&reg / , Cerco Ceram&reg / , Super porcelain EX-3&reg / , and bovine enamel. The wear rate, friction coefficient, and wear mechanisms of the A-W glass-ceramics were similar to currently used artificial dental materials.