The aim of this study was to evaluate color change of ultrathin ceramic laminates cemented with photocuring and dual resin cement by means of a split-mouth randomized clinical trial. The research subjects were 10 post graduation studentsfrom the Program in Dental Sciences, Federal University of Santa Maria. Two 0,3 mm-thick ceramic laminates built with lithium dissilicate ceramic IPS e.max Press (Ivoclar Vivadent) were cemented on the buccal surface of the participants second right and left premolars with the transparent shade of Variolink II (Ivoclar Vivadent), using the dual activation at one side and photoactivation at the other side, by a blind operator regarding the activation mode, after randomizing. The subjects were blind for the groups. Visual color evaluation was performed with a color scale Vita 3D-Master (Vita Zahnfabrik) by a calibrated and blind evaluator; a clinical spectrophotometer Vita Easyshade (Vita Zahnfabrik) was used for instrumental color evaluation 24 hours, 2 months, 4 months and 6 months after cementation. ΔE, Δa*, Δb* and ΔL* between the first and the other evaluations were calculated. Cement marginal staining was also evaluated. Considering visual evaluation, there was no alteration for the parameters value, hue and chroma in the groups. Paired sample t test did not show statistical difference between the groups for the parameters ΔE, Δa*, Δb* e ΔL* during the evaluated intervals. After 6 months, the photocuring group presented a mean ΔE=2,68 (±1,57) and the dual group, ΔE=2,36 (±0,69). Marginal discoloration was not observed. Longer follow-up results are necessary in order to determine if the two curing modes of Variolink II can be used for ceramic veneer cementation. / O objetivo do trabalho foi avaliar a alteração de cor de laminados cerâmicos ultrafinos cimentados com um cimento resinoso polimerizado por fotoativação e de forma dual, por meio de um ensaio clínico randomizado de boca dividida. Os participantes do estudo foram 10 estudantes do Programa de Pós-Graduação em Ciências Odontológicas da Universidade Federal de Santa Maria. Dois laminados cerâmicos de 0,3 mm de espessura, confeccionados com a cerâmica à base de dissilicato de lítio IPS e.max Press (Ivoclar Vivadent), foram cimentados, com o cimento Variolink II (Ivoclar Vivadent) transparente, sobre a face vestibular dos segundos pré-molares superiores direito e esquerdo dos participantes, em um lado com o modo de ativação dual e no lado oposto com o modo de ativação fotopolimerizável por um operador cegado quanto ao tipo de polimerização, após randomização. Os participantes estavam cegados para os grupos. Foi realizada avaliação visual da cor com escala de cores Vita 3D-Master (Vita Zahnfabrik) por um examinador calibrado e cegado e avaliação instrumental com o espectrofotômetro clínico Vita Easyshade (Vita Zahnfabrik) 24 horas, 2 meses, 4 meses e 6 meses após a cimentação, sendo calculados o ΔE, Δa*, Δb* e ΔL* entre a primeira e as demais leituras. Também foi feita avaliação da alteração de cor marginal do cimento. Para a avaliação visual, não houve alteração dos parâmetros valor, matiz e croma em nenhum grupo. O teste t para amostras pareadas não revelou diferença estatística entre os grupos para os parâmetros ΔE, Δa*, Δb* e ΔL nos intervalos avaliados, sendo que, após 6 meses, a média para o grupo fotoativado foi ΔE=2,68 (±1,57) e a média para o grupo dual foi ΔE=2,36 (±0,69). Não houve alteração de cor marginal. Resultados com maior tempo de acompanhamento são necessários para concluir se o cimento Variolink II pode ser utilizado nos dois modos de ativação para a cimentação de laminados cerâmicos.

Made available in DSpace on 2014-06-11T19:35:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-10-31Bitstream added on 2014-06-13T20:06:16Z : No. of bitstreams: 1 archangelo_cm_dr_araca.pdf: 3340208 bytes, checksum: 53b104f834f13f3fac3b5838d3d64527 (MD5) / Objetivo: O objetivo do presente estudo foi avaliar através do método dos elementos finitos tridimensional (3D FEA), o comportamento mecânico de uma faceta laminada de cerâmica e do cimento resionoso em um 1o pré-molar maxilar, variando a redução (parcial ou total) da cúspide vestibular. Material e método: Baseado em imagens micro-tomográficas (μCT) 2 modelos (M) tridimensionais foram construídos no programa Solidworks 2007 variando a redução da cúspide vestibular, sendo Mp o modelo composto pelo dente pré-molar restaurado com uma faceta laminada de cerâmica, com redução parcial da cúspide vestibular e Mt, o modelo semelhante ao Mp, porém com redução total da cúspide vestibular. O programa de elementos finitos ANSYS Workbench 10.0 foi utilizado para realizar as análises. O carregamento (150 N) foi aplicado próximo à ponta de cúspide vestibular, com 45º de inclinação. Foram utilizados os critérios da máxima tensão principal ( max) e da máxima tensão cisalhante ( shear) na faceta laminada e na camada de cimento resinoso. Resultados: O Mt mostrou menor shear em 9 das 12 áreas analisadas quando comparado ao Mp. O Mp mostrou menor variação da max (de -3,13 para 14,4 MPa) que o Mt para a lâmina de cerâmica (de -2,08 para 24,3 MPa) A camada de cimento apresentou variação de max semelhante entre os Mp e Mt. Os critérios de tensões utilizados não evidenciaram valores além dos limites estabelecidos para a falha estrutural do material estudado. Conclusão: O laminado cerâmico e a camada de cimento resinoso apresentaram comportamento mecânico favorável para a restauração do pré-molar frente ao carregamento adotado. O tipo de redução de cúspide não influenciou no aumento expressivo das tensões principal e cisalhante. O Mp apresentou menores valores de max em tração quando comparado ao Mt. O Mp e o Mt apresentaram comportamento favorável com relação as forças cisalhantes, sendo as maiores tensões. / Objectives: Using 3-D finite element analysis (FEA) and μCT data, the aim of this study was to evaluate the behavior of the laminate veneer and the resin luting cement in a maxillary premolar with the buccal cusp partially or completed covered. Material and method: 2 3-D FEA models of a maxillary premolar were built from μCT data. All models were restored with a feldspathic laminate veneer using Solidworks. A similar tooth reduction (0.5mm) was applied for two models. The buccal cusp reduction of the premolar followed two configurations: Model (Mt) - buccal cusp completely covered by veneer; and Model (Mp) - buccal cusp partially covered by veneer. The loading (150N, in 45o) was performed on the buccal cusp of each premolar. Appropriate boundary condition was applied at the periodontal ligament surfaces and ANSYS (10.0) was used to obtain the maximum shear stress ( shear) and maximum principal stress ( max) for the laminate veneer and resin luting cement layer. Results: The Mp showed higher shear than Mt in 9 to 12 analyzed areas. The Mp showed smallest variation of max in laminate veneer (from -3,13 to 14,4 MPa) compared with Mt (from - 2,08 to 24,3 MPa). The resin luting cement showed similar variation of max between Mp and Mt (from -3.13 to 12.2 MPa) and (from -1.61 to 14.1 MPa), respectively. None of the structures exceeded the ultimate tensile strength or the shear bond strength to dentin and enamel. Conclusion: The laminate veneer and the resin luting cement layer showed an adequate behavior when veneer was applied in premolars. Cusp reduction did not affect significant increase in max and shear. In general, the Mp showed better behavior ( max) than Mt. The Mt showed better behavior ( shear) than Mp.

Orientador: Eunice Teresinha Giampaolo / Banca: Gelson Luis Adabo / Banca: Carlos Eduardo Vergani / Banca: Maria da Glória Chiarello de Mattos / Banca: Ricardo Faria Ribeiro / Resumo: Este estudo teve como objetivo avaliar a efetividade de quatro condicionadores de metal (Metal Photo Primer, MPP; Cesead II Opaque Primer, OP; Targis Link, TL e Siloc, S) aplicados sobre diferentes superfícies das ligas de Ni-Cr, Co-Cr e do metal Ti Cp. Após o polimento metalográfico e jateamento com Al2O3, foram obtidos três grupos experimentais para cada metal : Grupo polimento (P) - controle; Grupo (J50), jateado com Al2O3 de 250 um. A esses grupos foram aplicados os condicionadores e as resinas opaca e de revestimento estético (Artglass). Decorridos 24 horas de armazenamento em água a 37ºC, cada grupo foi dividido em dois grupos e submetidos aos ensaios mecânicos de cisalhamento (0,5 mm/min.), um antes e outro após 500 ciclos térmicos (60ºC e 4ºC). As superfícies fraturadas foram analisadas e o padrão de falhas determinado. Adicionalmente foram feitas análises de MEV e EDS. Seguem os resultados para cada metal: Liga de Ni-Cr: para os Grupos P e J50, não foram observadas diferenças (p>0,05) nos valores médios de tensão de cisalhamento entre os condicionadores OP e TL e entre MPP e S, sendo maiores as médias dos dois primeiros. Não foram encontradas diferenças (p>0,05) entre as médias de tensão para os condicionadores do Grupo J250. No entanto, esses valores foram superiores aos do Grupo J50. Após a termociclagem, as médias para os condicionadores OP, S e TL não apresentaram aumento significante (p>0,05), enquanto a média para o MPP aumentou (p<0,05). Liga de Co-Cr, para o Grupo P, não foram observadas diferenças (p>0,05) nos valores médios de tensão entre os condicionadores OP e TL e entre MPP e S, sendo superiores as médias dos dois primeiros. As médias de tensão para o Grupo J250 foram estatisticamente maiores às do Grupo J50, ...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of the study was to evaluated the effect of three adhesive primers (Metal Photo Primer, MPP; Cesead II Opaque Primer, OP; Targis Link, TL) and a bonding system (Siloc, S) on the shear bond strength between a prosthetic composite material (Artglass) to Ni-Cr alloy (Wiron 99), Co-Cr alloy (Wironit), and CP Ti (Tritan). Disk patterns were cast of the 3 alloys. All the disk surfaces were abraded with No. 80, 320, and 600 SiC paper, respectively and three different surface treatment were applied: No. 600 SiC polishing, P; 50 mm Al2O3 sandblasting, S50; 250 mm Al2O3 sandblasting, S250. The composites (Artglass opaque and dentin) were applied using a cylindrical stainless steel split according to manufacturer's instructions then light polymerized. Specimens without primer and bonding system were also prepared as control. The specimens were stored in water a 37oC for 24 h and then shear bond strengths were determined both before and after immersed alternately in water baths at 4oC and 60oC for 15 seconds each for up to 500 thermal cycles before shear mode testing at a crosshead speed of 0.5 mm/min. Data were statistically analyzed using 3-way ANOVA and 1-way ANOVA, followed by Tukey multiple range intervals calculated at the 0.05 significance level. Fractured interfaces were analyzed by use of light microscopy and SEM. Results: Ni-Cr alloy: The bond strength of the P-OP/J50-OP group and P-TL/J50- TL group were statistically comparable (p>0,05) and exhibited greater strength than the P-MPP/J50-MPP group and P-S/J50-S (p<0,05). No significant differences were found among the four conditioners for J250 group (p>0,05), and these group showed the greater strength than the J50 group (p<0,05). After thermocycling, no significant differences (p>0,05) were found among the three primers (OP, S, TL) and the bond strength of MPP increased...(Complete abstract, click electronic access below) / Doutor

No description available.

Indiana University-Purdue University Indianapolis (IUPUI) / Statement of problem: Yttria-partially stabilized tetragonal zirconia polycrystal (Y-TZP) all-ceramic restorations have been reported to suffer from chipping or cracking of the veneering porcelain (VP) as the most common complication. There is little information in the literature regarding the influence of surface treatment on VP shear bond strength to Y-TZP after cyclic loading. Purpose of this study: The goals of this study were (1) to investigate the influence of zirconia surface treatments on veneering porcelain shear bond strength and (2) to investigate the influence of cyclic loading on the shear bond strength between VP and Y-TZP. Materials and Methods: 48 cylinder–shaped specimens (6mm in diameter and 4mm in height) were divided into 4 groups containing 12 specimens each according to the surface treatment. As a control group (C), no further treatment was applied to the specimens after grinding. Group H was heat-treated as a pretreatment according to the manufacturer’s recommendations. Group S was airborne-particle abraded with 50 µm alumina (Al2O3) particles under a pressure of 0.4 MPa for 10 seconds. In the group SH, the heat-treatment was performed after the airborne-particle abrasion. A VP cylinder (2.4 mm in diameter and 2 mm in height) was applied and fired on the prepared Y-TZP specimens. The shear bond strength was tested using a universal testing machine. Six specimens from each group were subjected to fatigue (10,000cycles, 1.5Hz, 10N load) before testing. Results: The 3-way ANOVA showed no statistically significant effect of surface treatment and cyclic loading on shear bond strength. The highest mean shear bond strength was recorded for the air-particle abrasion group without cyclic loading (34.1 + 10 MPa). The lowest mean shear bond strength was the air-particle abrasion group with cyclic loading (10.7 ± 15.4 MPa). Sidak multiple comparisons procedure demonstrated cyclic loading specimens had significantly lower shear bond strength than non-cyclic loading specimens after air-particle abrasion without heat treatment (p=0.0126) Conclusion: Within the limitations of this study, (1) Shear bond strength between Y-TZP and VP is not affected statistically by surface treatment using heat treatment, airborne-particle abrasion, and heat treatment after airborne-particle abrasion. (2) There is significant difference in shear bond strength with air-particle abrasion between with and without cyclic loading groups. This difference suggested that air-particle abrasion should be avoided in clinical situations as a surface treatment without heat treatment.

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Face checking in decorative maple veneered plywood panels is a significant problem for hardwood plywood manufacturers, furniture makers, cabinetmakers, and consumers. Efforts made by panel producers and researchers to minimize checking conducted to-­‐date have been limited, and produced contradictory results. In this study the impact of four manufacturing factors believed to contribute to check development in decorative maple veneer panels were determined. The factors investigated were face veneer thickness and preparation, lathe-­‐check orientation, adhesive and core type. An efficient, automated, optical technique based on digital image correlation principles was developed and used to detect and measure checks as they develop. The novel new method for characterizing check severity and development was effective in efficiently measuring checking for a substantial number of samples. The results of the factor screening analysis reveal intricate four way interactions between factor levels contribute to check development, and that some combinations are likely to exhibit much more checking than others. / Graduation date: 2013

I mitt examensarbete undersöker jag vilken putsmetod som lämpar sig bäst för putsning av infärgat faner utan att infärgat damm fastnar på oönskade områden. Testområdet har varit avgränsat till att undersöka detta problem tillsammans med andra, icke infärgade faner. Frågan är om det finns en metod som på ett effektivt och ergonomiskt sätt garanterar ett bra resultat? Mina tester utgår från om val av material, fiberriktning och snittyta har betydelse för hur det infärgade dammet fastnar på ytan. Min förhoppning är att hantverkare och formgivare ska ta hjälp av denna undersökning för att lättare kunna göra medvetna val där infärgade faner kombineras med andra träslag. Genom intervjuer med andra hantverkare, om deras erfarenheter har ett problemområde kartlagts utifrån vad som är mest relevant för undersökningen. Även litterära studier har gjorts för att bättre förstå träts anatomiska egenskaper. För att uppnå optimala förutsättningar för att infärgat damm inte ska fasta på oönskade områden visar testerna, genom att kombinera infärgat faner med ett bandporigt träslag som har en radiell snittyta tillsammans med en fiberriktning som ligger i samma riktning som putsriktningen, med en putsmetod där direkt sug över putsytan verkar samtidigt som putsningen ger bäst förutsättning för att infärgat damm inte fastnar på oönskade områden.