Made available in DSpace on 2015-09-17T15:24:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-12-02. Added 1 bitstream(s) on 2015-09-17T15:47:32Z : No. of bitstreams: 1 000843143.pdf: 1842870 bytes, checksum: 17eef18d8303e51e77d82360b9f3de64 (MD5) / O objetivo do estudo foi verificar a distribuição de tensões nas facetas cerâmicas confeccionadas com dois tipos de material: feldspato e dissilicato de lítio em quatro diferentes tipos de preparos limitados ao esmalte dental: (1) vestibular; (2) vestibular com redução incisal; (3) vestibular com cobertura incisal e (4) estendido, em duas situações oclusais: carga aplicada no terço incisal e no terço médio palatino, obtidas por meio de análise por elementos finitos. Os modelos tridimensionais foram realizados no software CAD Rhinoceros 4.0® utilizando um arquivo stl (estereolitografia) de um incisivo central superior, com dimensões médias encontradas na literatura, onde foram simuladas as condições utilizadas para realização de um teste experimental. Os modelos foram compostos por esmalte, dentina, polpa, poliéter (para simular ligamento periodontal), cerâmica e base e foram submetidos a cargas de 100 N sob angulação de 45º em relação ao plano oclusal. O pré-processamento e pós-processamento foram realizados pelo programa de elementos finitos Ansys® v.13.0. Os resultados foram apresentados em gráficos de tensão máxima principal, com seus respectivos valores numéricos representados em escala de cores. A análise de elementos finitos mostrou que os desenhos mais conservadores apresentaram uma melhor distribuição de tensão nos laminados cerâmicos de dissilicato de lítio em comparação à cerâmica feldspática, no entanto, a mais alta concentração de tensão foi encontrada nas facetas desse mesmo material no grupo estendido quando submetido à carga no terço médio palatino. O tipo do contato oclusal causou diferente distribuição de tensão entre os diferentes tipos de preparos, sendo que, o contato incisal promoveu uma maior concentração de tensão nas facetas realizadas com ambos materiais exceto no preparo estendido confeccionado com a porcelana de dissilicato de lítio / The purpose of this study was to verify the stress distribution in the ceramic veneers made with two types of porcelain: feldspathic and lithium disilicate in four different design types limited to dental enamel:(1) buccal preparation, (2) buccal preparation with incisal reduction, (3) buccal preparation with coverage incisal and (4) extended preparation in two different occlusal situations: load on the incisal third and the middle third palatine, through mathematical finite element method. Three-dimensional CAD models were performed in CAD Rhinoceros 4.0® using a stl file of a maxillary central incisor with average dimensions found in the literature, where conditions used for conducting an experimental test. The models were composed of enamel, dentin, pulp, polyether (to simulate the periodontal ligament), and ceramic base and underwent loads of 100 N under an angle of 45 degrees to the occlusal plane in the incisal and middle thirds of the palatal tooth region. Preprocessing and post processing by ANSYS® version 13.0 finite element program were performed. The results were presented in plots by principal maximum stress with their respective numerical values represented by the color scale. The finite element analysis showed that for the most conservative designs present a better stress distribution on veneers of lithium disilicate, nevertheless, the higher tensile stresses concentrations were found on veneers of same material for group subjected to palatal chamfer design when subjected to load in the middle third palate. The type of occlusal contact contact caused different distribution of tension among the different types of preparations design, and the incisal contact promoted higher stress concentration in both facets except the extended preparation performed with porcelain lithium disilicate

Orientador: Clovis Pagani / Co-orientador: Alexandre Luiz Souto Borges / Banca: Eduardo Bresciani / Banca: Eron Toshio Colato Yamamoto / Resumo: O objetivo do estudo foi verificar a distribuição de tensões nas facetas cerâmicas confeccionadas com dois tipos de material: feldspato e dissilicato de lítio em quatro diferentes tipos de preparos limitados ao esmalte dental: (1) vestibular; (2) vestibular com redução incisal; (3) vestibular com cobertura incisal e (4) estendido, em duas situações oclusais: carga aplicada no terço incisal e no terço médio palatino, obtidas por meio de análise por elementos finitos. Os modelos tridimensionais foram realizados no software CAD Rhinoceros 4.0® utilizando um arquivo stl (estereolitografia) de um incisivo central superior, com dimensões médias encontradas na literatura, onde foram simuladas as condições utilizadas para realização de um teste experimental. Os modelos foram compostos por esmalte, dentina, polpa, poliéter (para simular ligamento periodontal), cerâmica e base e foram submetidos a cargas de 100 N sob angulação de 45º em relação ao plano oclusal. O pré-processamento e pós-processamento foram realizados pelo programa de elementos finitos Ansys® v.13.0. Os resultados foram apresentados em gráficos de tensão máxima principal, com seus respectivos valores numéricos representados em escala de cores. A análise de elementos finitos mostrou que os desenhos mais conservadores apresentaram uma melhor distribuição de tensão nos laminados cerâmicos de dissilicato de lítio em comparação à cerâmica feldspática, no entanto, a mais alta concentração de tensão foi encontrada nas facetas desse mesmo material no grupo estendido quando submetido à carga no terço médio palatino. O tipo do contato oclusal causou diferente distribuição de tensão entre os diferentes tipos de preparos, sendo que, o contato incisal promoveu uma maior concentração de tensão nas facetas realizadas com ambos materiais exceto no preparo estendido confeccionado com a porcelana de dissilicato de lítio / Abstract: The purpose of this study was to verify the stress distribution in the ceramic veneers made with two types of porcelain: feldspathic and lithium disilicate in four different design types limited to dental enamel:(1) buccal preparation, (2) buccal preparation with incisal reduction, (3) buccal preparation with coverage incisal and (4) extended preparation in two different occlusal situations: load on the incisal third and the middle third palatine, through mathematical finite element method. Three-dimensional CAD models were performed in CAD Rhinoceros 4.0® using a stl file of a maxillary central incisor with average dimensions found in the literature, where conditions used for conducting an experimental test. The models were composed of enamel, dentin, pulp, polyether (to simulate the periodontal ligament), and ceramic base and underwent loads of 100 N under an angle of 45 degrees to the occlusal plane in the incisal and middle thirds of the palatal tooth region. Preprocessing and post processing by ANSYS® version 13.0 finite element program were performed. The results were presented in plots by principal maximum stress with their respective numerical values represented by the color scale. The finite element analysis showed that for the most conservative designs present a better stress distribution on veneers of lithium disilicate, nevertheless, the higher tensile stresses concentrations were found on veneers of same material for group subjected to palatal chamfer design when subjected to load in the middle third palate. The type of occlusal contact contact caused different distribution of tension among the different types of preparations design, and the incisal contact promoted higher stress concentration in both facets except the extended preparation performed with porcelain lithium disilicate / Mestre

O objetivo deste trabalho foi avaliar, in vitro, a influência de diferentes preparos dentais e dois diferentes tipos de cerâmica, sobre a resistência à fratura e o vedamento marginal de dentes restaurados com facetas laminadas. Foram utilizados 56 incisivos centrais, divididos em 7 grupos (incluindo grupo controle de dentes hígidos), diferenciados pelo preparo: preparos tipo janela, preparos com término em bordo reto e preparos com término em bordo envelopado e cerâmica utilizada: feldspática (Vita VM7 – Vita) e à base de dissilicato de lítio (IPS Empress II – Ivoclar Vivadent). Os dentes foram preparados com pontas diamantadas de forma padronizada, conforme os grupos acima, após foram moldados com silicona de adição para confecção dos laminados com os materiais citados. Após a cimentação dos laminados com cimento resinoso, os espécimes foram termociclados e moldados novamente para obtenção de réplicas em resina epóxi que foram avaliadas quanto à presença de fenda marginal em microscopia eletrônica de varredura (MEV). Os espécimes (dentes restaurados) foram submetidos ao teste de resistência à fratura em máquina de ensaio universal com velocidade de 1 mm/min. Os resultados foram tabulados e analisados estatisticamente pelos testes ANOVA e Qui², com nível de significância de 5%. O grupo controle apresentou a maior resistência à fratura. A resistência dos dentes restaurados com laminados foi influenciada significativamente pelo tipo de preparo (p=0,03) e pelo tipo de cerâmica (p=0,011) empregados. Quando comparados os dois tipos de cerâmica empregados, o desempenho superior foi para o sistema cerâmico à base de dissilicato de lítio, quando da presença de bordos reto e envelope. Com relação aos preparos, houve diferença para as cerâmicas feldspáticas, sendo superior o preparo janela. Para a avaliação de vedamento marginal, os grupos com preparo em bordo reto e envelopado associados à cerâmica à base de dissilicato de lítio não apresentaram fendas marginais. Porém, o grupo com preparo do tipo janela e cerâmica à base de dissilicato de lítio e o grupo com preparo em bordo reto e cerâmica feldspática apresentaram 75% de fendas presentes. Conclui-se que quando a cerâmica utilizada for feldspática, o preparo janela apresentou melhor resistência à fratura. Por outro lado, se a cerâmica utilizada for à base de dissilicato de lítio, o tipo de preparo não influenciou na resistência. Os laminados confeccionados com a cerâmica à base de dissilicato de lítio associados ao tipo de preparo reto ou envelopado apresentaram ausência de fenda (100%) e melhores resultados em relação à resistência à fratura para estes tipos de preparo. / The aim of this study was to evaluate in vitro the influence of different dental tooth preparations and two different types of ceramics on the fracture resistance and marginal sealing of teeth restored with veneers. 56 central incisors were divided into 7 groups (including the control group of sound teeth), by preparation: according to window, ending in straight edge and ending in overlap and ceramic used: feldspathic (Vita VM7 – Vita) and lithium disilicate (IPS Empress II – Ivoclar Vivadent). Teeth were prepared with diamond burs in a standardized manner, according above groups and were impressed with vinyl polysiloxane for the fabrication of veneers with the materials cited. After cementation of veneers with resin cement, specimens were thermocycled and molded again to obtain replicas in epoxy resin that were evaluated for the presence of marginal gap in scanning electron microscopy (SEM). The specimens (restored teeth) were tested for resistance to fracture in a universal testing machine with a crosshead speed of 1 mm / min. The results were statistically analyzed by ANOVA and Chi square test, with a significance level of 5%. The control group showed the highest fracture resistance. Restored teeth resistance was significantly influenced by the type of preparation (p = 0.03) and the ceramic type (p = 0.011). When comparing the two ceramic types, the superior performance was optained with lithium disilicate ceramic, associated with straight edges and overlap preparations. Regarding preparations showed differences within the feldspathic ceramics, being higher for the window preparation. Regarding marginal sealing, groups with board preparation in straight and overlap associated with lithium disilicate ceramic showed no marginal gaps. However, the group with window preparation and lithium disilicate ceramic and group preparation on board straight and feldspathic ceramic showed 75% of gap presence. It is concluded that when the ceramic used was felsdpathic the window preparation showed better fracture resistance. On the other hand, if the ceramic used was lithium disilicate, the type of preparation didn’t influence the fracture resistance. Laminates made with lithium disilicate ceramic associated with in straight or overlap preparation showed no gap formation (100%), presented the best results in relation to fracture resistance.

O objetivo deste trabalho foi avaliar, in vitro, a influência de diferentes preparos dentais e dois diferentes tipos de cerâmica, sobre a resistência à fratura e o vedamento marginal de dentes restaurados com facetas laminadas. Foram utilizados 56 incisivos centrais, divididos em 7 grupos (incluindo grupo controle de dentes hígidos), diferenciados pelo preparo: preparos tipo janela, preparos com término em bordo reto e preparos com término em bordo envelopado e cerâmica utilizada: feldspática (Vita VM7 – Vita) e à base de dissilicato de lítio (IPS Empress II – Ivoclar Vivadent). Os dentes foram preparados com pontas diamantadas de forma padronizada, conforme os grupos acima, após foram moldados com silicona de adição para confecção dos laminados com os materiais citados. Após a cimentação dos laminados com cimento resinoso, os espécimes foram termociclados e moldados novamente para obtenção de réplicas em resina epóxi que foram avaliadas quanto à presença de fenda marginal em microscopia eletrônica de varredura (MEV). Os espécimes (dentes restaurados) foram submetidos ao teste de resistência à fratura em máquina de ensaio universal com velocidade de 1 mm/min. Os resultados foram tabulados e analisados estatisticamente pelos testes ANOVA e Qui², com nível de significância de 5%. O grupo controle apresentou a maior resistência à fratura. A resistência dos dentes restaurados com laminados foi influenciada significativamente pelo tipo de preparo (p=0,03) e pelo tipo de cerâmica (p=0,011) empregados. Quando comparados os dois tipos de cerâmica empregados, o desempenho superior foi para o sistema cerâmico à base de dissilicato de lítio, quando da presença de bordos reto e envelope. Com relação aos preparos, houve diferença para as cerâmicas feldspáticas, sendo superior o preparo janela. Para a avaliação de vedamento marginal, os grupos com preparo em bordo reto e envelopado associados à cerâmica à base de dissilicato de lítio não apresentaram fendas marginais. Porém, o grupo com preparo do tipo janela e cerâmica à base de dissilicato de lítio e o grupo com preparo em bordo reto e cerâmica feldspática apresentaram 75% de fendas presentes. Conclui-se que quando a cerâmica utilizada for feldspática, o preparo janela apresentou melhor resistência à fratura. Por outro lado, se a cerâmica utilizada for à base de dissilicato de lítio, o tipo de preparo não influenciou na resistência. Os laminados confeccionados com a cerâmica à base de dissilicato de lítio associados ao tipo de preparo reto ou envelopado apresentaram ausência de fenda (100%) e melhores resultados em relação à resistência à fratura para estes tipos de preparo. / The aim of this study was to evaluate in vitro the influence of different dental tooth preparations and two different types of ceramics on the fracture resistance and marginal sealing of teeth restored with veneers. 56 central incisors were divided into 7 groups (including the control group of sound teeth), by preparation: according to window, ending in straight edge and ending in overlap and ceramic used: feldspathic (Vita VM7 – Vita) and lithium disilicate (IPS Empress II – Ivoclar Vivadent). Teeth were prepared with diamond burs in a standardized manner, according above groups and were impressed with vinyl polysiloxane for the fabrication of veneers with the materials cited. After cementation of veneers with resin cement, specimens were thermocycled and molded again to obtain replicas in epoxy resin that were evaluated for the presence of marginal gap in scanning electron microscopy (SEM). The specimens (restored teeth) were tested for resistance to fracture in a universal testing machine with a crosshead speed of 1 mm / min. The results were statistically analyzed by ANOVA and Chi square test, with a significance level of 5%. The control group showed the highest fracture resistance. Restored teeth resistance was significantly influenced by the type of preparation (p = 0.03) and the ceramic type (p = 0.011). When comparing the two ceramic types, the superior performance was optained with lithium disilicate ceramic, associated with straight edges and overlap preparations. Regarding preparations showed differences within the feldspathic ceramics, being higher for the window preparation. Regarding marginal sealing, groups with board preparation in straight and overlap associated with lithium disilicate ceramic showed no marginal gaps. However, the group with window preparation and lithium disilicate ceramic and group preparation on board straight and feldspathic ceramic showed 75% of gap presence. It is concluded that when the ceramic used was felsdpathic the window preparation showed better fracture resistance. On the other hand, if the ceramic used was lithium disilicate, the type of preparation didn’t influence the fracture resistance. Laminates made with lithium disilicate ceramic associated with in straight or overlap preparation showed no gap formation (100%), presented the best results in relation to fracture resistance.

The study was designed to evaluate the relative importance of certain factors influencing the strength properties of cold-pressed Douglas fir plywoods normal to glueline. In addition, estimates of strength values were also sought. Rotary-cut veneers were obtained from plywood mills; sawn veneers were prepared from lumber. A 2 x 3 x 3 factorial design was followed using veneer thicknesses of 1/10, 1/7, and 1/5 inch, and gluing pressures of 50, 200, and 350 psi. A cold-setting modified polyvinyl adhesive (Duro-Lok 50) was used in all 18 plywood blocks fabricated. From each of these, 8 tension, 4 compression and 3 glue shear specimens were prepared. Their dimensions were ½ x 1 x 4 1/2 inches, 1 x 1 x 4 1/2 inches and 1 x 3 1/4 x 3/5 inch, respectively. Plywoods of sawn veneers were only half as strong as solid wood in both compression and tension. Solid wood exceeded the compressive strength of rotary-cut veneer blocks by two, and tensile values by seven times. Stiffness of sawn veneers was twice that of rotary cut ones. The ratio of moduli of elasticity in compression to those in tension was found to approximate seven and six for the two veneer types, respectively. The difference between solid wood and sawn-veneer block strength might be attributed mainly to the influence of a suspected acid hydrolysis at the gluelines or possibly to specimen geometry. The much lower strength values of rotary-cut veneers must have resulted from the presence of lathe checks, and the lower quality of veneer surfaces. The functional dependence of all strength properties upon some independent factors, and the ranking of the latter, was established and evaluated by multiple regression analyses. The combination of the 16, 17 or 18 most important veneer and plywood variables accounted for practically all the variation, especially for rotary-cut veneers. In addition, the complete dependence of some plywood variables on independent veneer characteristics and gluing techniques were shown by regression equations. It should be noted that the three experimentally controlled factors, veneer type, veneer thickness and gluing pressure, were not always all included in the six most significant ones. The rank of variables was found to differ for each of the various strength properties observed. Analyses of variance were performed for both observed and adjusted values within each veneer type, both providing almost identical results. The high significance of veneer thickness has been shown for all strength properties, barring shear. This was explained by its strong correlation with a number of independent variables, such as glue content and specific gravity. Gluing pressure exerted a highly significant influence on all strength properties of rotary-cut veneer blocks, and in compressive stress and strain of sawn-veneer plywood construction. Its influence was attributed to the strong correlations indicated between it and other variables, for example, full compression and plastic deformation. Finally, the exploratory nature of the experiment was emphasized. / Forestry, Faculty of / Graduate

The influence of lathe checks on shear strength of Douglas fir plywood was investigated by means of impregnating lathe checks of rotary-cut veneer to various depths using a phenol-formaldehyde resin. Comparative tensile shear strength tests were conducted on a Table Model Instron machine and photographs taken at various stages of load application to illustrate the varied manner of failure. Strength of rotary-cut veneer plywood was about 60 to 70% that of sawn veneer plywood, but after the lathe checks of core veneer were impregnated by resin there was no significant difference between them. The shear strength (Y) was found to be highly correlated with penetration depth of adhesive into lathe checks (X). The linear relationship between these factors was: Y = 228.22 + 1.28052X (SE[subscript]E = 21.82; r = 0.893). Per cent wood failure estimated by conventional methods failed to relate to shear strength. Rather, the per cent wood failure occurring within 10$ of the initiation of an annual increment was found to be a better indicator of shear strength. Use of photography helped to explain more clearly stress distribution and wood failure in the specimens. It was found that the ultimate strength was reached in conventional plywood when the lathe checks were just opening. Core-impregnated plywood was used in a test to compare the tensile shear resistance when tight-side and loose-side of veneer was next to the glue line. Neither strength nor wood failure were significantly different between the two. Tensile shear strength for plywood made of impregnated core veneer and untreated face veneer was two to three times as high as that of conventional plywood. The per cent wood failure in core veneer and shear strength varied inversely. Results obtained in this study indicated that it is feasible to develop a plywood which has shear strength as high as 500 psi while remaining economical to manufacture. / Forestry, Faculty of / Graduate

Thesis (M.S.)--University of Michigan, 2003. / Includes bibliographical references.

Os objetivos deste trabalho foram avaliar a estabilidade de cor e capacidade de mascaramento até 1.000.000 de ciclos termomecânicos das facetas de cerâmica híbrida e cerâmica reforçada com dissilicato de lítio processadas pelo método de fresagem CAD/CAM; verificar a influência da cor do cimento em relação a cor final das facetas e a correspondência entre as pastas try-in; e as respectivas cores dos cimentos. Foram confeccionadas 60 facetas cerâmicas, pelo método de fresagem, que foram cimentadas com cimento fotopolimerizável (Variolink Esthetic LC), seguindo as orientações dos fabricantes, em réplicas de incisivos centrais escurecidos (C4) e não escurecidos (A2) e distribuídas nos grupos experimentais (n=10) DA2N, DC4N, DC4L, HA2N, HC4N, HC4L de acordo com o tipo de cerâmica dissilicato de lítio (D) e híbrida (H), cor do substrato A2 e C4, e cor do cimento neutral (N) e ligth (L). As leituras com espectrofotômetro foram realizadas previamente à cimentação das facetas, facetas + pastas Try-In, imediatamente após cimentação da faceta, após 48h, 72h e após ciclos termomecânicos (250.000, 500.000, 750.000 e 1.000.000) em máquina de ciclagem. Os dados foram analisados pelo teste ANOVA-2 medidas repetidas e teste Tukey (5%). Observou-se que ambas as cerâmicas apresentaram estabilidade de cor e capacidade de mascaramento, pois apesar de ocorrer diferença estatística em alguns grupos, todos os valores de E apresentaram-se abaixo de 1,7, ou seja, não são perceptíveis. Da mesma forma, verificou-se que a cor dos cimentos (neutral e light) não influenciou na cor final das restaurações, pois não houve diferença estatística significante comparando-se os grupos DC4N e DC4L como também entre HC4N e HC4L. Correlacionando-se as pastas try-in com as cores dos respectivos cimentos todos os valores obtidos para E ficaram abaixo de 3,3 que é considerado o limite como perceptível por observadores não treinados. Concluiu-se que as facetas de cerâmica híbrida e dissilicato de lítio apresentam muito boa estabilidade de cor ao longo do tempo e capacidade de mascaramento. Assim como, as diferentes cores de cimento não influenciam a cor final das facetas e as pastas try-in apresentam fidelidade em relação às respectivas cores dos cimentos. / The objectives of this work were to evaluate the color stability and masking ability up to 1,000,000 thermomechanical cycles of hybrid and reinforced with lithium disilicate ceramics processed by the CAD/CAM method; to verify the influence of cement color in relation to the final color of the veneers; and the correspondence between try-in and respective colors of the cements. 60 ceramic veneers were prepared using the milling method, which were cemented by light-curing cement (Variolink Esthetic LC) according to the manufacturer\'s instructions on replicates of darkened (C4) and nondarkened central incisors (A2) and distributed in the experimental groups (n=10) - DA2N, DC4N (D), DC4L, HA2N, HC4N, HC4L according to ceramic - lithium disilicate (D) and hybrid (H), substrate color - A2 and C4, and cement color - neutral (N) and ligth (L). The spectrophotometer measurements were performed prior to veneers cementation, veneers + try-In, immediately after cementing, after 48h, 72h and after thermomechanical cycles (250,000, 500,000, 750,000 and 1,000,000) in a cycling machine. Data were analyzed by ANOVA-2 repeated measures and Tukey test (5%). It was observed that both ceramics presented color stability and masking ability, because although there was a statistical difference in some groups, all values of E were below 1.7, ie, they are not perceptible. Likewise, it was found that the color of the cements (neutral and light) did not influence the final color of the restorations, since there was no significant statistical difference comparing the groups DC4N and DC4L as well as between HC4N and HC4L. By correlating the tryin with the colors of the respective cements all values obtained for E were below 3.3 which is considered the limit as perceived by untrained observers. It was concluded that hybrid ceramics and lithium disilicate veneers exhibit very good color stability over time and masking ability. As well as, the different cement colors do not influence the final color of the veneers and try-in pastes show similarity to the respective colors of the cements.

Orientador: Eduardo Passos Rocha / Banca: Paulo Henrique dos Santos / Banca: Reanto Herman Sundfeld / Banca: Gilberto Antônio Borges / Banca: Oswaldo Scopin de Andrade / Resumo: Com a evolução da adesão sobre tecidos dentários e cerâmicas vítreas na década de 80, tratamentos com abordagem mais conservadora em prótese dentária tem sido crescentemente sugeridos, com ênfase no uso de laminados cerâmicos, incluindo, mais recentemente, a possibilidade de tratamento sem a necessidade de desgaste na estrutura dentária. Embora sua possibilidade de aplicação seja real, poucos estudos longitudinais demonstram sua efetividade clínica. Assim, o objetivo deste estudo é fazer uma análise retrospectiva de 5 anos de experiência com restaurações laminados cerâmicos aplicados sobre dentes com ou sem preparo dentário. Materiais e Métodos: Um total de 240 restaurações foi realizado em 40 pacientes no segmento anterior superior, compreendendo de canino a canino, onde, em 29 pacientes, um total de 174 restaurações laminadas cerâmicas de dissilicato de lítio (LS2) foram realizadas sobre dentes com preparo dentário e, em 11 pacientes, 66 restaurações foram realizadas sobre dentes sem preparo dentário, entre os anos de 2007 e 2013. Estas restaurações foram avaliadas sobre os critérios de estabilidade de cor e integridade da restauração, descoloração e integridade da margem através dos critérios de Ryge modificados, California Dental Association (CDA/Ryge criteria). Resultados: Nos critérios de base utilizados, uma ampla porcentagem de restaurações foi classificada como A, e apenas 2 (1,15%) restaurações realizadas sobre dentes com preparo dentário falharam por fratura com a necessidade de troca (D), 4 (2,3%) tiveram pequenas alterações de cor, 1 (0,6%) teve descoloração superficial da margem (B) e 2 (1,15%) tiveram pequenas alterações na margem cervical (B). No grupo de restaurações sobre dentes sem preparo dentário, 7 (10,6%) restaurações tiveram descoloração superficial da margem (B) e nenhuma... / Abstract: Based on scientific and clinical evidence of adhesion to dental tissues and glass-ceramics in the 80s, more conservative treatment approach for dental prosthesis has been increasingly suggested. Among the most used therapies, the technique of ceramic laminate veneers are widely used in different clinical situations. Currently, from experience of applying the laminate restorations on teeth with dental preparation, some clinical situations have allowed the application of these restorations directly to the teeth without having to wear on tooth structure. Although the possibility of their application to real, few longitudinal studies have demonstrated the clinical effectiveness. The main of this study was to evaluate in a long-term of up to 5 years. In this study were evaluated ceramic laminate restorations applied to teeth with or without preparation. Materials and Methods: A total of 240 restorations were performed in 40 patients in the upper anterior segment, comprising from canine to canine, where in 29 patients, a total of 174 restorations laminated ceramic lithium disilicate (LS2) were performed on teeth with preparation, and 11 patients, 66 restorations were performed on teeth without preparation, between 2007 and 2013 at private clinic. Color stability and integrity of restoration, discoloration and integrity of the border were evaluated following modified California Dental Association (CDA / Ryge criteria). Results: a large percentage of restorations were classified as A, and only 2 (1.15%) restorations on teeth with preparation failed by fracture with the need to change (D), 4 (2, 3%) had minor color changes, 1 (0.6%) had superficial discoloration of the margin (B) and 2 (1.15%) had minor changes in the cervical margin (B). In the group of teeth without dental restorations, 7 preparation (10.6%) had superficial discoloration of restoration... / Doutor

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