Orientador: Regina Maria Puppin-Rontani / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-17T08:50:32Z (GMT). No. of bitstreams: 1 Sacramento_PatriciaAlmada_D.pdf: 3198869 bytes, checksum: 35adfba6168c7cf3012e88e5e9c2c3c5 (MD5) Previous issue date: 2010 / Resumo: Os objetivos nesta tese, apresentada em dois capítulos, foram avaliar o efeito da clorexidina-CHX e do monômero antibacteriano 12-metacriloxidodecilpiridíneo-MDPB na resistência e degradação da união resina/dentina desmineralizada por até doze meses de armazenamento. Capítulo 1: O objetivo deste estudo in vitro foi avaliar o efeito da CHX e/ou de diferentes sistemas adesivos na penetração dos monômeros na dentina desmineralizada, na formação e espessura da camada híbrida utilizando a técnica de Microscopia Confocal de Varredura a Laser (MCVL). Foram utilizados 3 sistemas adesivos: Clearfil SE Bond- SE (Kuraray), Clearfil Protect Bond - PB (Kuraray) e Adper Single Bond 2- SB (3M/ESPE) e um agente antimicrobiano: solução de digluconato de clorexidina 2% (FGM) preconizado para a limpeza da cavidade. Trinta terceiros molares hígidos foram distribuídos aleatoriamente em 6 grupos de acordo com os sistemas adesivos SE, PB e SB, com ou sem aplicação prévia da CHX. A dentina média foi exposta e desmineralizada artificialmente com gel ácido de carboximetilcelulose previamente ao procedimento de união. Os dados de MCVL foram analisados pelo teste estatístico Análise de Variância e teste de Tukey (P<0,05). A CHX e os sistemas adesivos não interferiram com a penetração dos monômeros na dentina desmineraliza. Todas as amostras apresentaram formação de camada híbrida, sendo mais espessa e menos homogênea nos grupos do SB, independente do uso da CHX. Concluiu-se que a CHX e os diferentes sistemas adesivos não afetaram a penetração dos monômeros em dentina desmineralizada. Somente o sistema adesivo interferiu com a espessura e homogeinidade da camada híbrida. Capítulo 2: O objetivo deste estudo in vitro foi: avaliar a influência CHX, do MDPB e o tempo de armazenamento na resistência e degradação da união resina/dentina desmineralizada através do teste de microcisalhamento (µSBS) e análise da nanoinfiltração. Foram utilizados 2 sistemas adesivos: Clearfil SE Bond- SE (Kuraray), Clearfil Protect Bond - PB (Kuraray). Cento e vinte terceiros molares hígidos foram distribuídos aleatoriamente em 12 grupos de acordo com os sistemas adesivos SE e PB, com ou sem aplicação prévia da CHX na superfície de união e tempo de armazenamento de 24 horas, 6 e 12 meses. A dentina média foi exposta e desmineralizada artificialmente. Após 24 horas de armazenamento o SE apresentou os menores valores de µSBS, não havendo diferença após 6 e 12 meses de armazenamento. A CHX não afetou os valores de µSBS. O modo de falha e a avaliação da nanoinfiltração foram analisados de forma descritiva. A nanoinfiltração da interface resina/dentina foi verificada em todos os grupos, havendo maior penetração da prata nos grupos de CHX. Um aumento no depósito de prata e decréscimo nos valores de µSBS foi notado em todos os grupos após 6 meses de armazenamento. A CHX e o MDPB não foram capazes de inibir a nanoinfiltração e o decréscimo na resistência de união. Conclui-se que a CHX não afetou a penetração dos sistemas adesivos na dentina desmineralizada, afetou a formação da camada híbrida, porém, não afetou os valores de resistência de união imediatos, que foram alterados pelo tempo de armazenamento, bem como a nanoinfiltração da prata na interface adesiva, após 6 e 12 meses. / Abstract: The objective of this Thesis, presented in two chapters, was to evaluate the effect of chlorhexidine-CHX and the antibacterial monomer 12-metacriloxydodecylpiridinium-MDPB on the bond strength and bonding degradation of the resin/demineralized dentin interface over twelve months of storage time. Chapter 1: The objective of this in vitro study was to evaluate the effect of CHX and/or different adhesive systems, in the penetration of monomers in demineralized dentin, as well as on the formation and thickness of the hybrid layer using Confocal Laser Scanning Microscopy (CLSM). Three adhesive systems were used: Clearfil SE Bond- (Kuraray), Clearfil Protect Bond - PB (Kuraray) and Adper Single Bond 2 - SB (3M/ESPE), and an antibacterial agent: 2% chlorhexidine solution (FGM) used for cavity disinfectant. Thirty sound third molars were randomly distributed into 6 groups according the adhesive systems SE, PB and SB, with or without previous CHX application. The middle dentin was exposed and the artificial caries lesion was developed with a carboxymethylcellulose acid gel previously the bonding procedure. CLSM images were analysed by the Analysis of Variance and Tukey's post hoc tests (P<0.05). The CHX and the MDPB did not interfere with the penetration of the adhesive systems in demineralized dentin. All the groups presented a hybrid layer formation, with significantly thicker and lower homogeneity in the SB groups, regardless of the CHX application. It was concluded that the CHX and the different adhesive system did not affect the penetration of monomers in the demineralized dentin. Only the adhesive system affected the thickness and homogeneity of hybrid layer. Chapter 2: The objective of this in vitro study was to evaluate the influence of CHX, MDPB and storage time in regard to the bond strength and the bonding degradation of resin/demineralized dentin interface by microshear (µSBS) and nanoleakage evaluation.Two adhesive systems were used: Clearfil SE Bond- SE (Kuraray), Clearfil Protect Bond- PB (Kuraray). One hundred twenty sound third molars were randomly distributed into 12 groups according to the adhesive systems, SE and PB, with or without previous CHX application on the bonding surface, and storage time of 24h, 6 and 12 months. The middle dentin was exposed and a artificial caries lesion was developed artificially. After 24h of storage, the SE groups presented the lower µSBS values, but they did not have statistical significant differences after 6 and 12 months of storage. The failure mode and the nanoleakage were evaluated descripitivelly. The nanoleakage of the resin/dentin interface was verified in all the groups, having a greater silver deposit in the CHX groups. An increase in the silver deposit and decrease in the µSBS values were noticed in all the groups after 6 months of storage. The CHX and the MDPB were not able to inhibit the nanoleakage and a decrease in bond strength. It was concluded that the CHX did not affect the penetration of the adhesive systems in the demineralized dentin, affected the hybrid layer formation, but it did not affect the imediate values of the bond strength, which were modified with the storage time, as was the nanoleakage in bonding interface, after 6 and 12 months. / Doutorado / Odontopediatria / Doutor em Odontologia

Orientador: Konradin Metze / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T20:44:11Z (GMT). No. of bitstreams: 1 Ferro_DanielaPeixoto_D.pdf: 2964245 bytes, checksum: 202d309cf65f632d47c7811d4958535d (MD5) Previous issue date: 2015 / Resumo: A aplicação integrada de técnicas modernas, como a Geração do Segundo Harmônico (SHG) e os tempos de vida da fluorescência (FLIM), com análise de imagens matemáticas nos permitem visualizar detalhes não vistos por microscopia de luz convencional. O objetivo deste estudo foi investigar se isto também pode ser aplicado para a investigação de tecido cicatricial. Foram estudados 28 casos de preparações histológicas de rotina, de quelóides, cicatrizes hipertróficas e normais. A Fluorescência de dois fótons e SHG foram obtidas por um microscópio multifóton (LSM 780 NLO-Zeiss), em objetiva de 40X e excitados por um laser Mai Tai de Ti: Safira (comprimento de onda de 940 nm). Foram adquiridas imagens em 3D e foram criadas imagens justapostas a fim de comparar diferentes cicatrizes ou várias regiões no interior da mesma cicatriz com análise de imagens informatizadas. Variáveis de Textura derivadas a partir da matriz de coocorrência das imagens de fluorescência mostraram diferenças significativas entre as cicatrizes normais, cicatrizes hipertróficas e quelóides. Para a análise do FLIM, foi utilizado um sistema composto por um microscópio confocal (LSM780-NLO- Zeiss), com objetiva de 40x e um sistema FLIM acoplado. As amostras foram excitadas por um laser de diodo a 405nm. Estudamos secções não coradas de 32 casos processados rotineiramente de tecido cicatricial incluídos em parafina. As áreas das regiões centrais e periféricas foram selecionadas aleatoriamente e comparadas. Os tempos de vida de fluorescência das hemácias serviram como padrão interno. Os tempos de vida do colágeno em áreas centrais em todos os tipos de cicatrizes foram significativamente mais longo do que em áreas periféricas. Houve correlação positiva entre os tempos de vida de fluorescência das hemácias e as fibras de colágeno entre os casos. Em resumo, o SHG e a técnica Flim revelam em cicatrizes rotineiramente processadas, características morfológicas dos tecidos, que não podem ser detectadas por microscopia de luz convencional / Abstract: The integrated application of modern techniques such as Second Harmonic Generation (SHG) and fluorescence lifetime imaging (FLIM) with mathematical image analysis enable us to visualize details not seen by conventional light microscopy. The aim of this study was to investigate whether this could also be true for the investigation of scar tissue. 28 routine histological preparations of keloids, hypertrophic and normal scars were studied. Two-photon fluorescence and SHG was obtained by a multiphoton microscope (LSM 780 NLO-Zeiss (at 40X objective magnification) and a Mai Tai Ti: Sapphire laser with excitation at 940 nm wavelength. 3D reconstructed patchwork images were created in order to compare different scars or various regions inside the same scar with computerized image analysis. Texture variables derived from the co- occurrence matrix of the fluorescence images showed significant differences between normal scars, hypertrophic scars and keloids. For FLIM analysis we used a system composed of a confocal microscope Zeiss LSM780 Upright-NLO with the 40x objective and a FLIM detection system. The samples were excited by a laser diode at 405nm. We studied unstained sections of 32 routinely processed and paraffin-embedded cases of scar tissue. Randomly selected areas of the central and peripheral regions were compared. The fluorescence lifetimes of red blood cells served as internal standard. Lifetimes of collagen in central areas of all scar types were significantly longer than in the periphery. There was a significant positive correlation between the fluorescence lifetimes of red blood cells and collagen fibers among the cases. In summary, SHG and FLIM techniques reveal in routinely processed scar tissue morphological characteristics, which cannot be detected by conventional light microscopy / Doutorado / Biologia Estrutural, Celular, Molecular e do Desenvolvimento / Doutora em Fisiopatologia Médica

Orientador: José Roberto Cury Saad / Resumo: A crescente demanda por tratamentos estéticos tem impulsionado o desenvolvimento de novos materiais e técnicas para tratamentos restauradores. Este estudo teve como objetivo avaliar o efeito de diferentes materiais restauradores e términos de preparo sobre a integridade marginal de coroas unitárias confeccionadas pelo sistema CAD/CAM (Computer Aided Desing/Computer Aided Manufacturing). Quarenta coroas unitárias foram confeccionadas utilizando quatro materiais: cerâmica vítrea a base de dissilicato de lítio (IPS e.max CAD, Ivoclar Vivadent), composto híbrido a base de cerâmica feldspática reforçada com polímeros (Vita Enamic, Vita Zahnfabrik), cerâmica de silicato de lítio reforçada com zircônia (Vita Suprinity, Vita Zahnfabrik) e compósito vítreo nanohíbrido (Brava Blocks, FGM) a partir de um preparo com quatro términos diferentes: chanfro (espessura de borda 0.8 mm), chanfro raso (0.4 mm), chanfro profundo (1.2 mm) e ombro (1.2 mm). O dente preparado foi escaneado com um scanner intraoral (CEREC Omnicam, Dentsply Sirona) e um projeto de restauração foi confeccionado com o uso de um software (CEREC SW 4.4, Dentsply Sirona). As coroas foram obtidas a partir da fresagem (Dental Milling Machine MC XL, Dentsply Sirona) de blocos para CAD/CAM dos materiais incluídos no estudo. Em seguida, as coroas obtidas a partir de dois materiais (IPS e.max CAD e Vita Suprinity) foram levadas a forno (Programat CS2The, Ivoclar Vivadent) para queima de cristalização. A integridade de borda das ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The crescent demand for aesthetic treatments has driven the development of new materials and techniques for restorative treatments. The aim of this study was to evaluate the effect of different restorative materials and finish line designs on the marginal integrity of single crowns obtained by CAD/CAM (Computer Aided Desing/Computer Aided Manufacturing). Forty crowns were made using four materials: Lithium disilicate-based vitreous ceramics (IPS e.max CAD, Ivoclar Vivadent), hybrid composite based on polymere-reinforced feldspathic ceramics (Vita Enamic, Vita Zahnfabrik), silicate ceramics lithium reinforced with zirconia (Vita Suprinity, Vita Zahnfabrik) and composite vitreous nanohybrid (Brava Blocks, FGM) from a preparation with four different finish line designs: chamfer (0.8 mm edge thickness), shallow chamfer (0.4 mm), deep chamfer (1.2 mm) and shoulder (1.2 mm). The prepared tooth was scanned with an intraoral scanner (CEREC Omnicam, Dentsply Sirona) and a restoration project was made using a software (CEREC SW 4.4, Dentsply Sirona). Crowns were obtained from milling (Dental Milling Machine MC XL, Dentsply Sirona) from CAD/CAM blocks of materials included in the study. Then, the crowns obtained from two materials (IPS e.max CAD and Vita Suprinity) were submitted (Programat CS2The, Ivoclar Vivadent) for burning of crystallization. The marginal integrity of the crowns was measured using the Laser Confocal Scanning Microscope (Lext OLS 4100, 3D measuring laser microscope,... (Complete abstract click electronic access below) / Mestre

Diss. (sammanfattning) Stockholm : Karol. inst., 2003. / Härtill 8 uppsatser.

In recent years, the confocal and two photon microscopes have become ubiquitous tools in life science laboratories. The reason for this is that both these systems can acquire three dimensional image data from biological specimens. Specifically, this is done by acquiring a series of two-dimensional images from a set of equally spaced planes within the specimen. The resulting image stack can be manipulated and displayed on a computer to reveal a wealth of information. These systems can also be used in time lapse studies to monitor the dynamical behaviour of specimens by recording a number of image stacks at a sequence of time points. The time resolution in this situation is, however, limited by the maximum speed at which each constituent image stack can be acquired. Various techniques have emerged to speed up image acquisition and in most practical implementations a single, in-focus, image can be acquired very quickly. However, the real bottleneck in three dimensional imaging is the process of refocusing the system to image different planes. This is commonly done by physically changing the distance between the specimen and imaging lens, which is a relatively slow process. It is clear with the ever-increasing need to image biologically relevant specimens quickly that the speed limitation imposed by the refocusing process must be overcome. This thesis concerns the acquisition of data from a range of specimen depths without requiring the specimen to be moved. A new technique is demonstrated for two photon microscopy that enables data from a whole range of specimen depths to be acquired simultaneously so that a single two dimensional scan records extended depth of field image data directly. This circumvents the need to acquire a full three dimensional image stack and hence leads to a significant improvement in the temporal resolution for acquiring such data by more than an order of magnitude. In the remainder of this thesis, a new microscope architecture is presented that enables scanning to be carried out in three dimensions at high speed without moving the objective lens or specimen. Aberrations introduced by the objective lens are compensated by the introduction of an equal and opposite aberration with a second lens within the system enabling diffraction limited performance over a large range of specimen depths. Focusing is achieved by moving a very small mirror, allowing axial scan rates of several kHz; an improvement of some two orders of magnitude. This approach is extremely general and can be applied to any form of optical microscope with the very great advantage that the specimen is not disturbed. This technique is developed theoretically and experimental results are shown that demonstrate its potential application to a broad range of sectioning methods in microscopy.

Over the past few decades, fluorescence microscopy has proven to become the most widely used imaging technique in the field of life sciences. Unfortunately, all classical optical microscopy techniques have one thing in common: their resolution is limited by the diffraction. Thankfully, due to the very strong interest, development of fluorescent microscopy techniques is very intense, with novel solutions surfacing repeatedly. The major breakthrough came with the appearance of super-resolution microscopy techniques, enabling imaging well below the diffraction barrier and opening the new era of nanoscopy. Among the fluorescent super-resolution techniques, Stimulated Emission Depletion (STED) microscopy has been particularly interesting, as it is a purely optical technique which does not require post image processing. STED microscopy has proven to resolve structures down to the molecular resolution. However, super-resolution microscopy is not a cure to all the problems and it also has its limits. What has shown to be particularly challenging, was the super-resolution imaging of thick samples. With increased thickness of biological structures, the aberrations increase and signal-to-noise (SNR) decreases. This becomes even more evident in the super-resolution imaging, as the nanoscopic techniques are especially sensitive to aberrations and low SNR. The aim of this work is to propose and develop a 3D STED microscope that can successfully image thick biological samples with nanoscopic resolution. In order to achieve that, adaptive optics (AO) has been employed for correcting the aberrations, using the indirect wavefront sensing approach. This thesis presents a custom built 3D STED microscope with the AO correction and the resulting images of thick samples with resolution beyond diffraction barrier. The developed STED microscope achieved the resolution of 60nm in lateral and 160nm in axial direction. What is more, it enabled super-resolution imaging of thick, aberrating samples. HeLa, RPE-1 cells and dopaminergic neuron differentiated from human IPS cells were imaged using the microscope. The results shown in this thesis present 3D STED imaging of thick biological samples and, what is particularly worth to highlight, 3D STED imaging at the 80μm depth, where the excitation and depletion beams have to propagate through the thick layer of tissue. 3D STED images at such depth has not been reported up to date.

Diss. (sammanfattning) Uppsala : Univ., 2002. / Härtill 7 uppsatser.

Thesis (Ph. D.)--University of Missouri--Columbia, 2004. / "May 2004." Typescript. Vita. Includes bibliographical references (leaves 166-179). Also issued on the Internet.

Orientadores: Altair Antoninha Del Bel Cury, Renata Cunha Matheus Rodrigues Garcia / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T01:31:00Z (GMT). No. of bitstreams: 1 Silva_WanderJoseda_D.pdf: 1629717 bytes, checksum: f107da940294da2fae00b7cf2e873b2b (MD5) Previous issue date: 2009 / Resumo: Os biofilmes de Cândida albicans formados sobre a superfície de resina de poli (metil metacrilato) (PMMA) apresentam alta virulência em função da liberação de enzimas hidrolíticas e são responsáveis pela candidose oral, infecção fúngica mais comum em usuários de próteses dentais removíveis. A organização do biofilme em várias camadas celulares envoltos por matriz de polissacarídeos extracelulares leva estas camadas celulares a estado metabólicos diferenciados e, portanto o uso da técnica de redução XTT ( 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide), cuja reação é dependente da atividade celular, pode ser questionada. Assim, objetivou-se no primeiro estudo que compõem este trabalho, padronizar e aperfeiçoar esta técnica através da suplementação de glicose. Para isso, biofilmes de Cândida albicans ATCC 90028 com tempos de crescimento de 24, 48 e 72 h foram avaliados. Para estabelecer o melhor tempo de incubação do XTT, este foi mantido a temperatura de 37 °C, em tempos de 90, 180 e 270 minutos. A fórmula padrão do teste XTT (controle) foi modificada com a adição de 50, 100 e 200 mM de glicose para os grupos experimentais. Os melhores resultados para a incubação foram observados com tempo de 180 minutos e para a suplementação de glicose à concentração de 200 mM (p<0,001). Uma vez determinada a melhor condição de leitura da bioatividade dos biofilmes, foi idealizado o segundo estudo, que objetivou a mensuraçâo da bioatividade e a análise morfológica de biofilmes de Cândida albicans desenvolvidos sobre a superfície de PMMA. Duas resinas a base de PMMA (banho de água e microondas) foram utilizadas como substrato para o desenvolvimento de biofilmes de duas cepas de Cândida albicans (ATCC 90028 e SC5314). A atividade metabólica destes biofilmes foi mensurada com a técnica modificada de redução mitocondrial do XTT. A análise da morfologia da fase de adesão e dos biofilmes de 24, 48 e 72 horas foi avaliada com o auxilio do microscópio de varredura confocal a laser e o microscópio eletrônico de transmissão A combinação das análises da morfologia com a mensuraçâo da bioatividade, permitiu verificar o desenvolvimento do biofilme, desde a fase de adesão, com alta atividade metabólica, evoluindo para a constituição de uma comunidade microbiana de alta complexidade estrutural com a presença de matriz de polissacarídeos extracelulares, através da qual os nutrientes se difundem, porém dotados de pouca atividade metabólica. O método de ativação das resinas não interferiu na bioatividade do biofílme e com a morfologia do biofllme formado para a cepa de Candida albicans SC 5314. Com base nestes estudos concluiu-se que a incubação de 180 minutos utilizando a suplementação de 200 mM de glicose apresenta resultados de atividade metabólica celular com a menor variação para o estudo de biofilmes de Candida albicans e que a morfologia do biofílme de ambas as espécies foi fator fundamental para as diferenças na estrutura do biofílme / Abstract: Candida albicans biofilms, developed on poly (methyl methacrylate) (PMMA) resin surfaces show high virulence index due to hydrolytic enzyme secretion and are responsible for oral candidosis in removable denture wearer. Since biofilms are surrounded by an extracellular polysaccharides matrix, the nutrients diffusion across the cell layers is difficulted, occasioning cell with different metabolic states. Thus, considering that the XTT reduction assay is dependent of cellular activity, its use for evaluating mature biofilms may lead to inaccuracies since biofilm bottom cells layers tends to be relatively quiescent at later stages of biofilm formation. The aim of the first study was the improvement of the XTT reduction assay by using glucose supplements in the standard XTT formulation. Candida albicans ATCC 90028 was used to form 24, 48 and 72 hours biofilm. The oxidative activity at 90, 180 and 270 minutes of incubation was evaluated. The standard XTT composition was modified by the addition of 50, 100 and 200 mM of glucose. The control comprised XTT formulation without glucose supplements. Biofilm growth yield after 180 min incubation, when evaluated with the 200 mM glucose supplemented XTT produced the most consistent readings on repetitive testing (pO.001), After the results of the determination of the oxidative activity assay using XTT supplemented by 200 mM glucose second study was conducted in which it was evaluated the characteristics of biofilm development of Candida albicans on two different poly (methyl methacrilate) resins (PMMA). Thus, two different Candida albicans strain (ATCC 90028 and SC5314) were allowed to develop its biofilm in two PMMA surfaces with different polymerization method: waterbath (WB) and microwave (MW). Different time points (adhesion, 24, 48 and 72 hours) were compared. Surface roughness (SR) and surface free energy (SFE) of PMMA specimens were previously measured. Oxidative activity was measured by XTT. Confocal images were used to measure bio-volume, thickness, biofilm roughness, diffusion and the of live/dead cells proportion in the different biofilm development stages. Cell counts were used to estimate the number of cells, and a combination of these techniques allowed to describe the Candida albicans biofilms development, starting from a small amount of cells with high oxidative activity, reaching to microbial community of complexity structural prosperities, with the presence of a matrix of polysaccharide, however with low oxidative activity. WB and MW showed no difference regards SR. and SFE means (p>0,05) and oxidative activity showed different results for each specie (p<0.001). Based on both studies, it can be conclude that 180 min incubation with the 200 mM glucose supplemented XTT generates more accuracy in oxidative activity results and also that the different polymerization method of PMMA are not able to interfere with biofilm development and main differences detected were related to the intrinsic characteristic of each Candida strain and biofilm development time / Doutorado / Protese Dental / Doutor em Clínica Odontológica

Orientador: Marcelo Giannini / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T10:19:14Z (GMT). No. of bitstreams: 1 Oliveira_MarceloTavaresde_D.pdf: 15233943 bytes, checksum: f6125d2132f3fd48d81be1d3cda778aa (MD5) Previous issue date: 2009 / Resumo: O uso de técnicas alternativas para preparo cavitário vem ganhando grande importância na Odontologia moderna. Entre estas tecnologias, o laser tem sido alvo de inúmeros estudos e para a realização de preparos cavitários o laser de Er:YAG é um dos mais indicados. Os objetivos deste estudo foram avaliar os efeitos de diferentes parâmetros de irradiação do substrato dentinário com laser de Er:YAG nos procedimentos restauradores adesivos e suas conseqüências sobre o substrato e sobre a união resina-dentina. Os testes foram realizados em superfícies dentinárias planificadas de terceiros molares humanos hígidos unidos a três diferentes sistemas adesivos (Single Bond 2 - 3M ESPE, Clearfil Protect Bond - Kuraray Medical Inc. e Clearfil Tri-S Bond - Kuraray Medical Inc.). Estas avaliações compreenderam o estudo da permeabilidade dentinária, da resistência de união, da longevidade e qualidade da união, além da análise da ultra-estrutura da interface de união através de microscopia eletrônica de transmissão e microscopia de varredura confocal laser. Os dados de permeabilidade e resistência de união foram analisados e submetidos à análise estatística com ANOVA 1-critério e ANOVA 3-critérios, respectivamente; ao encontrar diferenças significativas, o teste de Tukey foi utilizado. O nível de significância foi fixado em 5%. Os resultados mostraram ocorrer uma redução significativa na permeabilidade dentinária e que o parâmetro de 120mJ/4Hz foi o que promoveu a maior redução. Quanto à resistência de união, este estudo demonstrou que inicialmente, a irradiação com laser de Er:YAG reduz os valores de resistência de união, no entanto após 6 meses os valores são semelhantes tanto para o grupo controle, quanto para os grupos que foram irradiados. Além disso, pôde ser observado, que os sistemas autocondicionantes foram menos susceptíveis aos efeitos da irradiação do substrato, apresentando um comportamento mais uniforme. O sistema autocondicionante de dois passos também se mostrou mais estável ao longo do tempo. As imagens em microscopia eletrônica de transmissão e microscopia de varredura confocal laser, mostraram a formação de camada híbrida para todos os adesivos estudados com diferentes espessuras, quando aplicados sobre a dentina abrasionada. Não foi possível identificar camada híbrida uniforme e bem definida quando os sistemas foram aplicados em dentina irradiada com laser de Er:YAG, independentemente do parâmetro utilizado. Diante disso, os resultados sugerem que a irradiação da dentina com laser de Er:YAG reduz a permeabilidade dentinária, podendo influenciar na união dos adesivos à dentina nos períodos iniciais, entretanto após 6 meses os grupos irradiados foram iguais ao grupo controle. O exame ao microscópio revelou que a formação da camada híbrida é irregular e não-uniforme quando a dentina foi irradiada. / Abstract: The use of alternative techniques for cavity preparation is more common nowadays. Among these technologies, laser is the target of a great number of studies. The objectives of this study were to evaluate the effects of different parameters of dentin irradiation with Er:YAG laser on the adhesive procedures and their consequences over the substrate and resin dentin interface. Procedures were performed over flat dentin surfaces of human third molars bonded to three different adhesive systems ((Single Bond 2 - 3M ESPE, Clearfil Protect Bond - Kuraray Medical Inc. e Clearfil Tri-S Bond - Kuraray Medical Inc.). The evaluation tests were: dentin permeability, microtensile bond strengths, durability and the analysis of the ultra-structure using transmission electron microscope (TEM) and confocal laser scanning microscope (CSLM). Dentin permeability data and microtensile bond strength data were analyzed with one-way ANOVA and three-way ANOVA, respectively. Tukey test was used to point out differences among the tested groups. The significance level was fixed at 5%. Results showed a significative reduction on the dentin permeability and the 120mJ/4Hz parameter promoted the greatest reduction. For the microtensile bond strength test, this study showed that the irradiation with Er:YAG laser reduce the bond strength values at the baseline. After six months all groups became similar. Furthermore, self-etching systems were less affected by the Er:YAG laser irradiation. The two-step self-etching system seemed the more stable over time. TEM and CLSM images showed the hybrid-layer formation for all adhesive tested. The hybrid-layers had different thicknesses when the adhesive systems were bonded to abraded dentin. The observation of a uniform and well defined hybrid-layer was not possible when the adhesive systems were bonded to laser irradiated dentin, regardless of the used parameter. According to the data presented, dentin irradiation with Er:YAG laser reduce the permeability of the substrate, interfering on the bonding strength to dentin at the baseline, however, after six months laser irradiated groups were similar to control groups. Microscope analysis revealed that hybrid layer formation was irregular and non-uniform when dentin was laser irradiated. / Doutorado / Doutor em Materiais Dentários