Orientador: Luiz Felipe Valandro / Banca: Marco Antonio Bottino / Banca: Roberto Ruggiero Braga / Resumo: O objetivo deste trabalho foi avaliar a durabilidade da resistência adesiva entre um cimento resinoso e uma cerâmica feldspática, o pH e o ângulo de contato da superfície cerâmica, submetida à diferentes tratamentos de superfície. Para análise do pH de superfície foram confeccionados 96 discos (8X3mm) da cerâmica feldspática (Vita VM7), os quais, foram divididos em 12 grupos (n=8): CS1- sem condicionamento; CS2- ácido fluorídrico (HF) 9% 1 min; CS3- CS2+lava/seca; CS4- CS3+silano (S); CS5- HF 4% 1 min; CS6- CS5+lava/seca; CS7- CS6+silano; CS8- HF 5% 1 min; CS9- CS8+lava/seca; CS10- CS9+silano 20 5min; CS11- CS9+neutralização+lava/seca+ultra-som; CS12- CS11+siano. Após, o pH foi medido com um peagâmetro digital. Para a análise do ângulo de contato foram confeccionados 40 discos com as mesmas dimensões (n=8): CS1- sem condicionamento; CS2- HF 9%; CS3- HF 4%; CS4- HF 5%; CS5- HF 5%+neutralização+lava/seca+ultra-som. As medidas foram realizadas com um Goniômetro. Para a resistência de união, foram confeccionados 40 blocos (6,4X6,4X4,8mm), os quais foram submetidos aos tratamentos (n=10): CS1- HF 9% 1 min; CS2- HF 4% 1 min; CS4- HF 5% 1 min; CS5- CS3+neutralização+lava/seca+ultra-som. Os espécimes foram armazenados em água destilada (37°C) por 24h e seccionados nos sentidos x e y. Os corpos-deprova obtidos foram divididos em 2 condições (Seco- ensaio imediato; TCarmazenagem + termociclagem) e submetidos ao teste de microtração. Na análise do pH, CS6 obteve o maior resultado e CS5, CS8 e CS2, obtiveram os menores valores estatisticamente. Para o ângulo de contato, CS1 obteve médias maiores comparados aos outros grupos. Para resistência de união, CS2=CS1>CS3=CS4, independente do fator armazenagem. Somente o CS4 sofreu redução na resistência adesiva após TC. Conclui-se que a neutralização parece afetar negativamente a resistência adesiva... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to evaluate the tensile bond strength of a resin-based cement to a feldspathic ceramic (Vita VM7), the pH and the contact angle on a ceramic surface, after submitted to surface conditioning methods. To analyze the pH of the ceramic surface, ninety six disks (8x3mm) of VM7 were fabricated and divided into 12 groups (n=8) according to each treatment condition (CS): CS1- without surface conditioning; CS2- hidrofluoridric acid (HF) 9% 1 min; CS3- CS2+wash/dry; CS4- CS3+silane (S); CS5- AHF 4% 1 min; CS6- CS5+wash/dry; CS7- CS6+silane; CS8- HF 5% 1 min; CS9- CS8+wash/dry; CS10- CS9+silane 5min; CS11- CS9+neutralizer+wash/dry+ ultrasonic cleaning; CS12- CS11+silane. Then, pH was measure using a digital peagameter. Another forty disks (8X3mm) were fabricated and divided into 5 groups to analyze the contact angle: CS1-without conditioning; CS2- HF 9%; CS3- HF 4%; CS4- HF 5%; CS5- HF 5%+ neutralizer +wash/dry+ultra-som, all groups were analyzed by means of a Goniômetro. Forty blocks (6,4x6,4x4,8mm) were fabricated, divided into 5 groups (n=10) and submitted to surface treatments to evaluate the bond strength: CS1- HF 9% 1 min; CS2- HF 4% 1 min; CS4- HF 5% 1 min; CS5- CS3+ neutralizer +wash/dry+ ultrasonic cleaning. The specimens were storage in distilled water at 37°C for 24 hours and cut into to axes (x and y), then the bar specimens obtained were submitted to 2 conditions (Dry - immediate test; TC - storage + thermocycling) and to the microtensile bond strength test. pH values were significantly high for CS6 compared to that of CS5, CS8 and CS2. CS1 had the highest contact angle. In the microtensile bond strength, CS2=CS1>CS3=CS4, independently from the storage condition. CS4 had the lowest microtensile bond strength value after TC. The neutralization decrease the bond strength significantly, which was evidenced by the high contact angles after the surface neutralization. / Mestre

Silicon carbide (SiC) is a wide band-gap semiconductor with advantageous electrical and thermal properties making it attractive for high temperature and power applications. However, difficulties with oxide/SiC structures have posed challenges to the development of practical MOS-type devices. Surface conditioning and oxidation of 4H-SiC were investigated using a novel sequential afterglow processing approach combined with the unique capabilities of non-contact corona-Kelvin metrology. The use of remote plasma assisted thermal oxidation facilitated film growth at low temperature and pressure with the flexibility of sequential in-situ processing options including pre-oxidation surface conditioning. Corona-Kelvin metrology (C-KM) provided a fast, non-destructive method for electrical evaluation of oxide films and semiconductor surfaces. Non-contact C-KM oxide capacitance-voltage characteristics combined with direct measurement of SiC surfaces using C-KM depletion surface barrier monitoring and XPS analysis of surface chemistry were interpreted relating the impact of afterglow conditioning on the surface and its influence on subsequent oxide thin film growth. Afterglow oxide films of thicknesses 50-500 angstroms were fabricated on SiC epi-layers at low growth temperatures in the range 600-850°C, an achievement not possible using conventional atmospheric oxidation techniques. The inclusion of pre-oxidation surface conditioning in forming gas (N2:H2)* afterglow was found to produce an increase in oxide growth rate (10-25%) and a significant improvement in oxide film thickness uniformity. Analysis of depletion voltage transients on conditioned SiC surfaces revealed the highest degree of surface passivation, uniformity, and elimination of sources of charge compensation accomplished by the (N2:H2)* afterglow treatment for 20 min. at 600-700°C compared to other conditioning variations. The state of surface passivation was determined to be very stable and resilient when exposed to a variety of temporal, electrical, and thermal stresses. Surface chemistry analysis by XPS gave evidence of nitrogen incorporation and a reduction of the C/Si ratio achieved by the (N2:H2)* afterglow surface treatment, which was tied to the improvements in passivation, uniformity, and growth rate observed by non-contact C-KM measurements. Collective results were used to suggest a clean, uniform, passivated, Si-enriched surface created by afterglow conditioning of 4H-SiC as a sequential preparation step for subsequent oxidation or dielectric formation processing.

Made available in DSpace on 2014-06-11T19:28:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-07-26Bitstream added on 2014-06-13T18:58:09Z : No. of bitstreams: 1 amaral_r_me_sjc.pdf: 3501879 bytes, checksum: f350dffbc6a2244de5a8f806e30513e5 (MD5) / O objetivo deste trabalho foi avaliar a durabilidade da resistência adesiva entre um cimento resinoso e uma cerâmica feldspática, o pH e o ângulo de contato da superfície cerâmica, submetida à diferentes tratamentos de superfície. Para análise do pH de superfície foram confeccionados 96 discos (8X3mm) da cerâmica feldspática (Vita VM7), os quais, foram divididos em 12 grupos (n=8): CS1- sem condicionamento; CS2- ácido fluorídrico (HF) 9% 1 min; CS3- CS2+lava/seca; CS4- CS3+silano (S); CS5- HF 4% 1 min; CS6- CS5+lava/seca; CS7- CS6+silano; CS8- HF 5% 1 min; CS9- CS8+lava/seca; CS10- CS9+silano 20 5min; CS11- CS9+neutralização+lava/seca+ultra-som; CS12- CS11+siano. Após, o pH foi medido com um peagâmetro digital. Para a análise do ângulo de contato foram confeccionados 40 discos com as mesmas dimensões (n=8): CS1- sem condicionamento; CS2- HF 9%; CS3- HF 4%; CS4- HF 5%; CS5- HF 5%+neutralização+lava/seca+ultra-som. As medidas foram realizadas com um Goniômetro. Para a resistência de união, foram confeccionados 40 blocos (6,4X6,4X4,8mm), os quais foram submetidos aos tratamentos (n=10): CS1- HF 9% 1 min; CS2- HF 4% 1 min; CS4- HF 5% 1 min; CS5- CS3+neutralização+lava/seca+ultra-som. Os espécimes foram armazenados em água destilada (37°C) por 24h e seccionados nos sentidos x e y. Os corpos-deprova obtidos foram divididos em 2 condições (Seco- ensaio imediato; TCarmazenagem + termociclagem) e submetidos ao teste de microtração. Na análise do pH, CS6 obteve o maior resultado e CS5, CS8 e CS2, obtiveram os menores valores estatisticamente. Para o ângulo de contato, CS1 obteve médias maiores comparados aos outros grupos. Para resistência de união, CS2=CS1>CS3=CS4, independente do fator armazenagem. Somente o CS4 sofreu redução na resistência adesiva após TC. Conclui-se que a neutralização parece afetar negativamente a resistência adesiva... / The aim of this study was to evaluate the tensile bond strength of a resin-based cement to a feldspathic ceramic (Vita VM7), the pH and the contact angle on a ceramic surface, after submitted to surface conditioning methods. To analyze the pH of the ceramic surface, ninety six disks (8x3mm) of VM7 were fabricated and divided into 12 groups (n=8) according to each treatment condition (CS): CS1- without surface conditioning; CS2- hidrofluoridric acid (HF) 9% 1 min; CS3- CS2+wash/dry; CS4- CS3+silane (S); CS5- AHF 4% 1 min; CS6- CS5+wash/dry; CS7- CS6+silane; CS8- HF 5% 1 min; CS9- CS8+wash/dry; CS10- CS9+silane 5min; CS11- CS9+neutralizer+wash/dry+ ultrasonic cleaning; CS12- CS11+silane. Then, pH was measure using a digital peagameter. Another forty disks (8X3mm) were fabricated and divided into 5 groups to analyze the contact angle: CS1-without conditioning; CS2- HF 9%; CS3- HF 4%; CS4- HF 5%; CS5- HF 5%+ neutralizer +wash/dry+ultra-som, all groups were analyzed by means of a Goniômetro. Forty blocks (6,4x6,4x4,8mm) were fabricated, divided into 5 groups (n=10) and submitted to surface treatments to evaluate the bond strength: CS1- HF 9% 1 min; CS2- HF 4% 1 min; CS4- HF 5% 1 min; CS5- CS3+ neutralizer +wash/dry+ ultrasonic cleaning. The specimens were storage in distilled water at 37°C for 24 hours and cut into to axes (x and y), then the bar specimens obtained were submitted to 2 conditions (Dry - immediate test; TC - storage + thermocycling) and to the microtensile bond strength test. pH values were significantly high for CS6 compared to that of CS5, CS8 and CS2. CS1 had the highest contact angle. In the microtensile bond strength, CS2=CS1>CS3=CS4, independently from the storage condition. CS4 had the lowest microtensile bond strength value after TC. The neutralization decrease the bond strength significantly, which was evidenced by the high contact angles after the surface neutralization.

O objetivo deste estudo foi avaliar o efeito do condicionamento de superfície de uma vitrocerâmica 100% cristalina e altamente bioativa (Biosilicato®) e de seus produtos de dissolução iônica sobre diferentes parâmetros do desenvolvimento do fenótipo osteogênico in vitro. Previamente ao plaqueamento de células osteogênicas de calvárias de ratos, discos de Biosilicato® foram condicionados, por 3 dias, em meio de cultura suplementado, com ou sem soro fetal bovino a 10%. Células osteogênicas expostas aos produtos de dissolução iônica do Biosilicato® foram também cultivadas sobre lamínulas de vidro bioinerte. Discos de Biosilicato e lamínulas de vidro foram utilizados como controles. Os resultados mostraram que o tratamento de superfície de Biosilicato® aumenta expressivamente a concentração de silício e cálcio no meio de cultura. Em 1, 3 e 7 dias, foram determinados os maiores valores de viabilidade celular em superfícies de Biosilicato® condicionado, enquanto que entre os grupos de lamínulas de vidro, observou-se menor viabilidade em culturas expostas aos produtos de dissolução iônica do Biosilicato®. Em 3 dias, células sobre todas as superfícies de Biosilicato® apresentavam-se menos espraiadas quando comparadas àquelas sobre lamínulas de vidro; neste período, a topografia das superfícies dos grupos de Biosilicato® caracterizava-se por rede de cavidades na submicro e nanoescala, enquanto que a lamínula apresentava superfície plana. Alterações no padrão de marcação das proteínas citoesqueléticas actina, vimentina, tubulina e vinculina, da subunidade de integrina α5 e da fibronectina eram observadas apenas em células crescidas sobre as superfícies de Biosilicato®. Ao final da fase proliferativa (7 dias), foram observados maiores níveis relativos de expressão de RNA mensageiro para Runx2, sialoproteína óssea (BSP) e fosfatase alcalina (ALP) em culturas crescidas sobre superfícies condicionadas de Biosilicato®; a exposição aos produtos de dissolução iônica aumentou a expressão de Runx2 e ALP nos grupos de lamínula de vidro. Em 14 dias, culturas sobre Biosilicato® condicionado em meio de cultura com soro exibiam áreas mais extensas de mineralização. Os resultados deste estudo mostraram que o condicionamento de superfícies de Biosilicato® previamente ao plaqueamento celular favorece aspectos da interação célula-substrato, promovendo maior viabilidade celular e aumentando e/ou acelerando o desenvolvimento do fenótipo osteogênico in vitro. A exposição aos produtos de dissolução iônica do Biosilicato® inibe a progressão de culturas osteogênicas sobre lamínulas de vidro bioinerte, apesar de aumentar a expressão de marcadores osteoblásticos. / The aim of the present study was to evaluate the effect of surface conditioning of a highly bioactive, fully crystalline glass-ceramic in the Na2O-CaO-SiO2-P2O5 system (Biosilicate®) and of its ionic dissolution products on key parameters of the development of the osteogenic phenotype in vitro. Rat calvaria-derived osteogenic cells were plated on Biosilicate® discs that were pre-conditioned either with supplemented culture medium or serum-free medium for 3 days. In addition, osteogenic cells grown on bioinert glass coverslips were exposed to the ionic dissolution products of the Biosilicate®. The results showed that the supplemented culture medium used for the Biosilicate® surface conditioning exhibited a high concentration silicium and calcium. At 1, 3, and 7 days, cell viability was significantly higher for the conditioned Biosilicate® sufaces, whereas reduced cell viability was observed for cultures grown on glass coverslips and exposed to the ionic dissolution products of Biosilicate®. At day 3, cells grown on Biosilicate® groups were less spread compared with those on glass coverslips. At the same time point, whereas the surface topography of glass coverslips was smooth, Biosilicate® discs exhibited a network of submicron and nanoscale pits. Changes in the labeling pattern of the cytoskeleton proteins actin, vimentin, tubulin and vinculin, and of α5 integrin and fibronectin were only observed for cells grown on Biosilicate® surfaces. At the end of the proliferative phase (day 7), expression levels of Runx2, alkaline phosphatase (ALP) and bone sialoprotein (BSP) mRNAs were significantly higher for cultures grown on conditioned Biosilicate® surfaces; the exposure of cells to the ionic dissolution products increased Runx2 and ALP mRNA levels. At day 14, significantly more extensive areas of matrix mineralization were detected for cultures grown on Biosilicate® discs that were pre-conditioned with supplemented culture medium. The results showed that the conditioning of Biosilicate® surfaces with culture medium prior to cell plating supports key aspects of cell-substrate interactions, increasing and/or accelerating expression of the osteoblastic cell phenotype. Furthermore, the exposure of cells to the ionic dissolution products of Biosilicate® inhibits the progression of osteogenic cell cultures on bioinert glass coverslips, despite its positive effect on expression of osteoblastic markers.

O objetivo deste estudo foi avaliar o efeito do condicionamento de superfície de uma vitrocerâmica 100% cristalina e altamente bioativa (Biosilicato®) e de seus produtos de dissolução iônica sobre diferentes parâmetros do desenvolvimento do fenótipo osteogênico in vitro. Previamente ao plaqueamento de células osteogênicas de calvárias de ratos, discos de Biosilicato® foram condicionados, por 3 dias, em meio de cultura suplementado, com ou sem soro fetal bovino a 10%. Células osteogênicas expostas aos produtos de dissolução iônica do Biosilicato® foram também cultivadas sobre lamínulas de vidro bioinerte. Discos de Biosilicato e lamínulas de vidro foram utilizados como controles. Os resultados mostraram que o tratamento de superfície de Biosilicato® aumenta expressivamente a concentração de silício e cálcio no meio de cultura. Em 1, 3 e 7 dias, foram determinados os maiores valores de viabilidade celular em superfícies de Biosilicato® condicionado, enquanto que entre os grupos de lamínulas de vidro, observou-se menor viabilidade em culturas expostas aos produtos de dissolução iônica do Biosilicato®. Em 3 dias, células sobre todas as superfícies de Biosilicato® apresentavam-se menos espraiadas quando comparadas àquelas sobre lamínulas de vidro; neste período, a topografia das superfícies dos grupos de Biosilicato® caracterizava-se por rede de cavidades na submicro e nanoescala, enquanto que a lamínula apresentava superfície plana. Alterações no padrão de marcação das proteínas citoesqueléticas actina, vimentina, tubulina e vinculina, da subunidade de integrina α5 e da fibronectina eram observadas apenas em células crescidas sobre as superfícies de Biosilicato®. Ao final da fase proliferativa (7 dias), foram observados maiores níveis relativos de expressão de RNA mensageiro para Runx2, sialoproteína óssea (BSP) e fosfatase alcalina (ALP) em culturas crescidas sobre superfícies condicionadas de Biosilicato®; a exposição aos produtos de dissolução iônica aumentou a expressão de Runx2 e ALP nos grupos de lamínula de vidro. Em 14 dias, culturas sobre Biosilicato® condicionado em meio de cultura com soro exibiam áreas mais extensas de mineralização. Os resultados deste estudo mostraram que o condicionamento de superfícies de Biosilicato® previamente ao plaqueamento celular favorece aspectos da interação célula-substrato, promovendo maior viabilidade celular e aumentando e/ou acelerando o desenvolvimento do fenótipo osteogênico in vitro. A exposição aos produtos de dissolução iônica do Biosilicato® inibe a progressão de culturas osteogênicas sobre lamínulas de vidro bioinerte, apesar de aumentar a expressão de marcadores osteoblásticos. / The aim of the present study was to evaluate the effect of surface conditioning of a highly bioactive, fully crystalline glass-ceramic in the Na2O-CaO-SiO2-P2O5 system (Biosilicate®) and of its ionic dissolution products on key parameters of the development of the osteogenic phenotype in vitro. Rat calvaria-derived osteogenic cells were plated on Biosilicate® discs that were pre-conditioned either with supplemented culture medium or serum-free medium for 3 days. In addition, osteogenic cells grown on bioinert glass coverslips were exposed to the ionic dissolution products of the Biosilicate®. The results showed that the supplemented culture medium used for the Biosilicate® surface conditioning exhibited a high concentration silicium and calcium. At 1, 3, and 7 days, cell viability was significantly higher for the conditioned Biosilicate® sufaces, whereas reduced cell viability was observed for cultures grown on glass coverslips and exposed to the ionic dissolution products of Biosilicate®. At day 3, cells grown on Biosilicate® groups were less spread compared with those on glass coverslips. At the same time point, whereas the surface topography of glass coverslips was smooth, Biosilicate® discs exhibited a network of submicron and nanoscale pits. Changes in the labeling pattern of the cytoskeleton proteins actin, vimentin, tubulin and vinculin, and of α5 integrin and fibronectin were only observed for cells grown on Biosilicate® surfaces. At the end of the proliferative phase (day 7), expression levels of Runx2, alkaline phosphatase (ALP) and bone sialoprotein (BSP) mRNAs were significantly higher for cultures grown on conditioned Biosilicate® surfaces; the exposure of cells to the ionic dissolution products increased Runx2 and ALP mRNA levels. At day 14, significantly more extensive areas of matrix mineralization were detected for cultures grown on Biosilicate® discs that were pre-conditioned with supplemented culture medium. The results showed that the conditioning of Biosilicate® surfaces with culture medium prior to cell plating supports key aspects of cell-substrate interactions, increasing and/or accelerating expression of the osteoblastic cell phenotype. Furthermore, the exposure of cells to the ionic dissolution products of Biosilicate® inhibits the progression of osteogenic cell cultures on bioinert glass coverslips, despite its positive effect on expression of osteoblastic markers.

Indiana University-Purdue University Indianapolis (IUPUI) / Repair is an alternative treatment option in many cases to replacement of resin matrix composite restoration. However, aged resin matrix composites have a limited number of carbon-carbon double bonds to adhere to a new layer of rein. Therefore, surface treatments of the aged resin matrix composite surface prior to repairing could improve the repair bond strength. The objectives of this study were to: 1) To evaluate various surface treatments on shear bond strength of repair between aged and new microhybrid resin matrix composite, and 2) To assess the influence of applying a silane coupling agent after surface treatments. Eighty disk-shaped resin matrix composite specimens were fabricated and thermocycled 5000 times prior to surface treatment. Specimens were randomly assigned to one of the three surface treatments (n = 20): 1) Airborne abrasion with 50 μm aluminum oxide, 2) Tribochemical silica coating (CoJet), or 3) Er,Cr:YSGG laser and control group (n = 20). Specimens were cleaned with 35-percent phosphoric acid, rinsed, and dried. Each group was assigned into two subgroups (n =10): a) no silanization, and b) with silanization. Adhesive agent was applied and new resin matrix composite was bonded to each conditioned surface. Bond strength was evaluated by shear test. Data were analyzed with a two-way ANOVA model. The interaction between conditioning and silanization was significant(p = 0.0163), indicating that comparisons of silanization must be evaluated for each conditioning method, and that comparisons of conditioning methods must be evaluated separately with and without silanization. Airborne particle abrasion showed significantly higher repair bond strength than Er,Cr:YSGG laser without silanization (p < 0.0001) and with silanization(p = 0.0002), and higher repair bond strength than the control without silanization (p < 0.00001) and with silanization (p < 0.00001). Airborne particle abrasion did not have significantly different in repair bond strength than Tribosilica coating without silanization (p = 0.70) or with silanization (p = 0.33). Tribosilica coating had significantly higher repair bond strength than Er,CR:YSGG laser without silanization (p < 0.0001) and with silanization (p < 0.0001), and significantly higher repair bond strength than control without silanization (p < 0.0001), but not with silanization (p =0.16). Er,CR:YSGG laser and control did not have significantly different repair bond strength without silanization (p = 1.00) or with silanization (p = 0.11). There was no effect of silanization on repair bond strength overall (p = 0.34) for any of the surface conditioning methods (p = 0.76 for airborne particle abrasion; p = 0.39 for tribosilica coating; p = 1.00 for Er,Cr:YSGG laser, or p = 0.39 for control). Airborne particle abrasion with 50-μm aluminum oxide particle and tribochemical silica coating followed by the application of bonding agent provided the highest shear bond strength values, suggesting that they might be adequate methods to improve the quality of the repairs of resin-matrix composites.