Les travaux présentés dans ce manuscrit abordent l’étude de deux familles distinctes de molécules photoactivables induisant des processus biologiques différents sous excitation 2-photon : les triphénylamines (TPAs) et les Nanotriggers de deuxième génération (NTs). Les TPAs présentent un grand intérêt pour la thérapie photodynamique (PDT) 2-photon, grâce à leur section efficace d’absorption 2-photon élevées (325-764 GM) et leur capacité à induire la mort cellulaire, médiée par la production d’espèces réactives de l’oxygène (ROS) sous excitation 1- ou 2-photon. De plus, leur forte fluorescence permet d’imager la mort cellulaire grâce à un comportement singulier dans les cellules : les TPAs sont initialement localisés dans le cytoplasme des cellules vivantes, principalement au niveau mitochondrial, mais se re-localisent dans le noyau des cellules en apoptose. Les NTs de deuxième génération ont été conçus suivant le modèle de NT1, le premier Nanotrigger synthétisé. Leur structure générale a été conceptualisée pour se fixer à la protéine NO synthase (NOS) et générer un potentiel redox élevé uniquement sous excitation lumineuse, initiant ainsi un transfert d’électron à travers la NOS aboutissant à une production de NO. Les structures chimiques des sept molécules nouvellement synthétisées diffèrent à plusieurs niveaux. Cette étude a permis d’identifier, parmi les sept NT de deuxième génération, deux molécules ayant la capacité de pénétrer dans les cellules endothéliales, de cibler la eNOS et d’initier le transfert d’électron à travers la eNOS sous excitation 1- ou 2-photon. Les expériences réalisées au cours de cette thèse sur les deux familles de composés, ont également permis de mettre en évidence les relations entre la structure des molécules et les différents mécanismes induits par leur photo-activation. / The presented works in this manuscript approach the study of two distinct families of photoactivatable molecules that induce different biological processes under 2-photon excitation : triphenylamines (TPAs) and second generation Nanotriggers (NTs). TPAs present a great interest for 2-photon photodynamic therapy (PDT), thanks to their high 2-photon absorption cross-sections (325-764 GM) and their ability to induce cell death mediated by reactive oxygen species (ROS) production under 1- or 2-photon excitation. Moreover, their high fluorescence allows the imaging of cell death due to their particular behaviour in cells: TPAs initially localize in the cytoplasm of living cells, but translocate to the nucleus of apoptotic cells. Second generation NTs were designed based on the model of NT1, the first synthesized Nanotrigger. Their general structure has been designed to bind to the NO Synthase protein (NOS) and generate a high redox potential under excitation only, leading to the initiation of the electron flow through the protein and resulting in NO production. The chemical structures of the seven newly synthesized molecules differ on many levels. This study has identified, among the seven second generation NTs, two molecules which are able to penetrate in endothelial cells, target eNOS and initiate the electron transfer at the eNOS level under 1- or 2-photon excitation. The experiments presented in this thesis allowed to establish structure-activity relationships for each compound family regarding the different mechanisms induced by their photoactivation.

O objetivo deste trabalho foi investigar a otimização da fotocura de uma resina composta odontológica por meio da fotoativacão conjugada. A fotoativação foi realizada com LED e ultrassom e LED em resina pré-aquecida. Foi utilizado LED com comprimento de onda centrado em 470 nm com densidade de potência de 600 mW/cm2 para os testes com ultrassom e pré-aquecimento associados. A aplicação de ondas mecânicas (ultrassom) ocorreu com frequência de 30 kHz (modo contínuo) e 1 MHz (modo contínuo e pulsado), e o pré-aquecimento foi feito com as temperaturas de 37oC, 50oC e 60oC. Foi avaliada também a influência da irradiância de luz na contração de polimerização por meio da técnica de variação de contraste Speckle. A resina composta utilizada foi a Filtek Z250TM (3M ESPE) na cor A2. Foram realizados os testes de microdureza Vickers e grau de conversão para a aplicação de ultrassom conjugado com LED. Para a resina pré-aquecida fotoativada com LED foram realizados realizado os testes de microdureza Vickers, grau de conversão, fluorescência, estabilidade de cor, contração e adaptação marginal. Os resultados mostraram-se promissores para a otimização da fotocura. / The aim of this study was to investigate the optimization of photo-cure of dental composite resin by combined curing methods. The curing was performed associating ultrasound and LED and LED with pre-heating composite resin. The irradiation performed was centered at 470 nm with power density of 600 mW/cm2 for the ultrasound and pre-heating association. The application of mechanical waves (ultrasound) was performed using 30 kHz (continuous mode) and 1 MHz (continuous and pulsed), and pre-heating with temperatures of 37oC, 50oC and 60oC. The influence on polymerization shrinkage was also evaluated through the variation of speckle contrast. The composite resin used was FiltekTM Z250 (3M ESPE) shade A2. Vickers microhardness and degree of conversion for the application of ultrasound in conjunction with LED were investigated. For the pre-heating composite resin and LED photo-activation, the Vickers microhardness, degree of conversion, fluorescence, color stability, shrinkage and marginal adaptation were performed. The results showed to be promising for the optimization of photo-cure of dental resins.

O objetivo deste trabalho foi investigar a otimização da fotocura de uma resina composta odontológica por meio da fotoativacão conjugada. A fotoativação foi realizada com LED e ultrassom e LED em resina pré-aquecida. Foi utilizado LED com comprimento de onda centrado em 470 nm com densidade de potência de 600 mW/cm2 para os testes com ultrassom e pré-aquecimento associados. A aplicação de ondas mecânicas (ultrassom) ocorreu com frequência de 30 kHz (modo contínuo) e 1 MHz (modo contínuo e pulsado), e o pré-aquecimento foi feito com as temperaturas de 37oC, 50oC e 60oC. Foi avaliada também a influência da irradiância de luz na contração de polimerização por meio da técnica de variação de contraste Speckle. A resina composta utilizada foi a Filtek Z250TM (3M ESPE) na cor A2. Foram realizados os testes de microdureza Vickers e grau de conversão para a aplicação de ultrassom conjugado com LED. Para a resina pré-aquecida fotoativada com LED foram realizados realizado os testes de microdureza Vickers, grau de conversão, fluorescência, estabilidade de cor, contração e adaptação marginal. Os resultados mostraram-se promissores para a otimização da fotocura. / The aim of this study was to investigate the optimization of photo-cure of dental composite resin by combined curing methods. The curing was performed associating ultrasound and LED and LED with pre-heating composite resin. The irradiation performed was centered at 470 nm with power density of 600 mW/cm2 for the ultrasound and pre-heating association. The application of mechanical waves (ultrasound) was performed using 30 kHz (continuous mode) and 1 MHz (continuous and pulsed), and pre-heating with temperatures of 37oC, 50oC and 60oC. The influence on polymerization shrinkage was also evaluated through the variation of speckle contrast. The composite resin used was FiltekTM Z250 (3M ESPE) shade A2. Vickers microhardness and degree of conversion for the application of ultrasound in conjunction with LED were investigated. For the pre-heating composite resin and LED photo-activation, the Vickers microhardness, degree of conversion, fluorescence, color stability, shrinkage and marginal adaptation were performed. The results showed to be promising for the optimization of photo-cure of dental resins.

Made available in DSpace on 2017-07-10T14:57:32Z (GMT). No. of bitstreams: 1 HELOUISE_ RIGHI.pdf: 781690 bytes, checksum: e73794e76d42164775e107e6f2160613 (MD5) Previous issue date: 2016-03-02 / With the ample craving for teeth whitening, it is fundamental the production of increasingly clearer materials and also a good color stability, before the possible degradation which are exposed. The camphorquinone (CQ) is the photo initiator most widely applied on the dental composite, but it has the yellow coloration and suffers darkening when exposed to ultraviolet light (UV), endangering the maintenance of the esthetics harmony. The goal of this study was to evaluate in vitro the effect of the photo initiator Phenylpropanodione, singly or in association with the CQ, about the color stability of the resinous photoactive cement and its bond adhesive resistence, by microshear. The null hypotheses are: i) the photo initiator PPD does not interfere with the color changing of the resin cement, after the photoaging motivated by prolonged exposure to UV light; and ii) the photo initiator PPD does not interfere with the resistance of the adhesive bond of resin cement to the ceramic. Four resinous cements where used, which one of them was commercial (RelyX Venner, 3M/ESPE) and three experimental, differing each other's photo initiator's concentration. For the color analysis, ceramic discs were cemented above the bovine dentine, simulating the indirect restorations (n=8), being exposed to 120 h of UV, and tested about the color alterations which were measured applying the CIELab scale, by spectrophotometer of reflectance. The obtained datas were verified about the normal distribution, for then being submited to ANOVA and to the complementary test Tukey, all with 5% significance. The results of color analysis do not statistically significant difference to E of 4 cements studied neither to L , a and b . For the Union of Resistance of all cements studied showed statistically significant differences among themselves, with the highest for commercial cement RelyX Venner® (29.07 MPa), followed by cement with CQ (21.74 MPa) , and cement CQ + PPD (19.09 MPa); and the lowest result was obtained with the cement using only the PPD as photoinitiator (13.99 MPa) . Therefore to the parameters studied in this work, the PDD was not advantageous as photoinitiator resin cements, because made low bond strength value ceramics and not demonstrated superiority as for color stability . / Com o amplo anseio pelo branqueamento dental, é fundamental a produção de materiais cada vez mais claros e que também possuam boa estabilidade de cor, ante às possiveis degradações a que ficam expostos. A Canforoquinona (CQ) é o fotoiniciador mais amplamente empregado nos compósitos odontológicos, porém tem coloração amarelada e sofre escurecimento ao ser exposta à luz ultra violeta (UV), comprometendo a manutenção da harmonia estética. O objetivo deste estudo foi avaliar in vitro o efeito do fotoiniciador Phenilpropanodiona (PPD), isoladamente ou em associação com a CQ, sobre a estabilidade de cor de cimentos resinosos fotoativados, e sua resistência de união adesiva à cerâmica, por teste de microcisalhamento. As hipóteses nulas testadas são: i) o fotoiniciador PPD não interfere na alteração de cor de cimentos resinosos, após o foto envelhecimento provocado por exposição prolongada a luz UV; e ii) o fotoiniciador PPD não interfere na resistência da união adesiva de cimentos resinosos à cerâmica. Foram utilizados 4 cimentos resinosos, sendo um comercial (RelyX Venner®) e 3 experimentais, diferindo entre si quanto ao tipo e concentração dos fotoiniciadores. Para a análise de cor, foram cimentados discos cerâmicos sobre dentina bovina, simulando restaurações indiretas (n=8), sendo expostos a 120 h de UV, e testados quanto às alterações de cor, que foram mensuradas empregando a escala CIELab, por meio de espectrofotômetro de reflectância. Os dados obtidos foram verificados quanto a distribuição normal, para então serem submetidos a ANOVA e ao teste complementar Tukey, todos com significância de 5%. Os resultados do teste de cor não apresentam diferença estatisticamente significante para o E dos 4 cimentos estudados, nem tampouco para L, a e b. Para a resistência de união, todos os cimentos estudados apresentaram diferenças estatisticamente significantes entre si, com o maior resultado para o cimento comercial RelyX Venner® (29,07 Mpa), seguido pelo cimento com CQ (21,74 Mpa), e então pelo cimento de CQ+PPD (19,09 Mpa); e o menor resultado foi obtido com o cimento utilizando apenas o PPD como fotoiniciador (13,99 Mpa). Portanto, para os parâmetros estudados neste trabalho, o PDD não se mostrou vantajoso como fotoiniciador de cimentos resinosos, já que apresentou baixo valor de resistência de união à cerâmica e não demonstrou superioridade quanto à estabilidade de cor.

Halorhodospira halophila photoactive yellow protein (PYP) is a promising candidate to act as a photoswitching domain in engineered proteins due to the structural changes that occur during its photocycle. Absorption of a photon of wavelength 446 nm triggers trans to cis isomerization of its 4-hydroxycinnamic acid chromophore leading to large structural perturbations in the protein, particularly in the N-terminus. In the dark, a slower cis to trans reisomerization of the chromophore restores the protein’s native fold. The fusion of proteins to PYP’s N-terminus may therefore enable photomodulation of the activity of the attached protein. To test this hypothesis, this thesis descibes genetically encoded photoswitchable DNA-binding proteins that were developed by fusing the prototypical leucine-zipper type DNA-binding protein GCN4 bZIP to the N-terminus of PYP. Five different fusion constructs of full length or truncated GCN4 bZIP and full length PYP as well as fusion constructs of full length GCN4 bZIP and N-terminally truncated PYP mutants were designed in a structure-based approach to determine if the dimerization and DNA binding activities could be controlled by the PYP photocycle. Extensive biophysical characterization of the fusion constructs in the dark and under blue light irradiation using electronic absorption, circular dichroism and fluorescence spectroscopic techniques were performed. As all the fusion proteins could complete photocycles, the DNA binding abilities of the dark and light-adapted states of the proteins were characterized using spectroscopic techniques as well as by the electrophoretic mobility shift assay. All the fusion constructs maintained DNA-binding abilities, however they each differed in their affinities and the extent to which they were activated by blue light irradiation. The reasons for these differences in DNA-binding abilities and photoactivation are explored. Using the results from the characterization of these constructs, proposals are also made to develop more robust genetically encoded photoactivatable DNA-binding proteins of the same type.

Halorhodospira halophila photoactive yellow protein (PYP) is a promising candidate to act as a photoswitching domain in engineered proteins due to the structural changes that occur during its photocycle. Absorption of a photon of wavelength 446 nm triggers trans to cis isomerization of its 4-hydroxycinnamic acid chromophore leading to large structural perturbations in the protein, particularly in the N-terminus. In the dark, a slower cis to trans reisomerization of the chromophore restores the protein’s native fold. The fusion of proteins to PYP’s N-terminus may therefore enable photomodulation of the activity of the attached protein. To test this hypothesis, this thesis descibes genetically encoded photoswitchable DNA-binding proteins that were developed by fusing the prototypical leucine-zipper type DNA-binding protein GCN4 bZIP to the N-terminus of PYP. Five different fusion constructs of full length or truncated GCN4 bZIP and full length PYP as well as fusion constructs of full length GCN4 bZIP and N-terminally truncated PYP mutants were designed in a structure-based approach to determine if the dimerization and DNA binding activities could be controlled by the PYP photocycle. Extensive biophysical characterization of the fusion constructs in the dark and under blue light irradiation using electronic absorption, circular dichroism and fluorescence spectroscopic techniques were performed. As all the fusion proteins could complete photocycles, the DNA binding abilities of the dark and light-adapted states of the proteins were characterized using spectroscopic techniques as well as by the electrophoretic mobility shift assay. All the fusion constructs maintained DNA-binding abilities, however they each differed in their affinities and the extent to which they were activated by blue light irradiation. The reasons for these differences in DNA-binding abilities and photoactivation are explored. Using the results from the characterization of these constructs, proposals are also made to develop more robust genetically encoded photoactivatable DNA-binding proteins of the same type.

Durante o processo inicial da reação de presa, o cimento de ionômero de vidro modificado por resina (CIVMR) apresenta baixo módulo de elasticidade, característica importante quando utilizado como base de restaurações com resina composta, por diminuir o estresse de contração de polimerização nas paredes cavitárias. O presente estudo teve como objetivo analisar a influência da técnica de polimerização de uma base CIVMR (VitrebondTM) por resina na interface dente/restauração de resina composta, através de teste de microtração e análise em microscopia confocal. Foram utilizados 30 dentes molares humanos hígidos extraídos, nos quais foram confeccionadas cavidades padronizadas em sua face oclusal (5mm de comprimento x 3mm de largura x 4,5mm profundidade). O sistema adesivo utilizado AdperTM Single Bond 2 foi marcado previamente com Rodamina B (0,16mg/ml), para possibilitar a análise em microscópio confocal. Os dentes foram divididos em 3 grupos: Grupo 1 (controle): base de CIVMR VitrebondTM + fotoativação + sistema adesivo + resina composta FiltekTM Z250; Grupo 2: base de CIVMR VitrebondTM + sistema adesivo + fotoativação por 30 segundos simultânea dos dois materiais + resina composta FiltekTM Z250; Grupo 3: base de CIVMR por resina VitrebondTM + tempo de espera de 60 segundos + fotoativação + sistema adesivo + resina composta FiltekTM Z250. Após a restauração, os dentes permaneceram em água deionizada em estufa a 37 ºC por 24 horas. Em seguida, foram seccionados com disco de diamante em fatias de aproximadamente 0,8mm no sentido vestíbulo-lingual. Uma fatia de cada dente foi separada aleatoriamente para análise da presença de fendas na interface dentina/resina composta em microscopia confocal. As demais fatias foram seccionadas para a confecção de palitos, para os testes de microtração. Os resultados de resistência de união foram submetidos à análise de variância a um critério ANOVA a 5% e teste de qui-quadrado para as variáveis de presença de fendas marginais e tipo de fratura resultante (p<0,05). Não houve diferença estatisticamente significante entre os três grupos (p=0,644) com relação à resistência adesiva e tipo de fratura, predominando a fratura do tipo adesiva para todos os grupos. Quanto à presença de fendas marginais internas, foi evidenciada sua presença nos grupos 2 e 3, sem diferença estatisticamente significante entre os três grupos testados (p=0,082). Conclui-se, portanto, que a técnica de polimerização da base de cimento de ionômero de vidro modificado por resina não influencia na resistência adesiva da interface dente/restauração de resina composta. / During the initial process of setting reaction, the resin-modified glass-ionomer cement (RMGIC) shows low modulus of elasticity, which is an important characteristic when RMGIC is used as a liner in resin composites restorations, because it decreases the polymerization shrinkage stress in cavity walls. The aim of this study was to analyze the influence of polymerization techniques of resin-modified glass-ionomer cement used as a liner on the adhesive interface dentin/resin by microtensile test and confocal microscopic analysis. Standardized occlusal cavity preparations (5mm length x 3mm wide x 4.5mm depth) were prepared in 30 human extracted molars. For the analysis at the confocal microscope, the adhesive system AdperTM Single Bond 2 was previously marked with rodhamine B (0.16mg/ml). The tooth were divided into three groups: Group 1 (control): RMGIC liner VitrebondTM + photoactivation for 30 seconds + adhesive system + resin composite Filtek TM Z250; Group 2: RMGICs liner VitrebondTM + adhesive system + simultaneous photoactivation of both materials + resin composite FiltekTM Z250; Group 3: RMGICs liner VitrebondTM+ 60 seconds delay time + photoativation for 30 seconds + adhesive system + resin composite FiltekTMZ250. Specimens were stored at 37ºC in deionized water for 24 hours. After this period, tooth was sectionated in 0.8mm slices (buco-lingual). One slice of each tooth was randomly selected for confocal microscopy for analysis of the interface resin/dentin. The other slices were sectionated in sticks (mesio-distal) for microtensile test. One-way ANOVA (p<0.05) showed no significant statistical difference among groups 1, 2 and 3 (p=0.644). Quisquare test showed no significant statistical difference of type of fracture (adhesive fracture was predominant) and presence of gap at the interface dentin/resin among groups. (p=0.082). It can be concluded, that polymerization technique of resin-modified glassionomer cement (RMGIC) did not influence bond strength and dentin/resin composite interface.

Le monoxyde d’azote (NO), dont le rôle biologique a été découvert à la fin du 20ème siècle, est impliqué dans la régulation de nombreux processus à l’échelle de la cellule et de l’organisme. Sa biosynthèse est réalisée par les enzymes NO synthases (NOS), et met en jeu la liaison de NADPH à leur domaine réductase suivie d’une série de transfert d’électrons vers leur domaine oxygénase, où la formation de NO se produit par oxydation de la L-arginine. En s’inspirant de mimes photo-activables de NADPH précédemment décrits dans la littérature, appelés nano-déclencheurs (NT, de l’anglais nanotriggers), induisant la production de NO par illumination, nous avons conçu et synthétisé de nouvelles générations de composés potentiellement capables d’initier l’activité catalytique de NOS sous irradiation. Ils comportent une unité de reconnaissance de NOS dérivée de l’adénosine et une unité chromophorique de type diaminophényl butadiène, liées entre elles par un groupement triazole. Ces structures modulables, facilement assemblées par chimie « click » ont permis la préparation d’une librairie de nano-déclencheurs, dont les propriétés photophysiques et la stabilité dans des conditions physiologiques ont été évaluées. Ces nouvelles générations de composés offrent des perspectives intéressantes pour le contrôle de processus biologiques par la lumière. / Nitric oxide (NO), whose biological role has been discovered in the late 20th century, is involved in the regulation of many processes in cell and organism. Its biosynthesis is carried out by enzymes named nitric oxide synthases (NOS) and involves NADPH binding to their reductase domain followed by a series of electron transfers to their oxygenase domain, where the formation of NO takes place by oxidation of L-arginine. Inspired by photoactivatable NADPH mimics called nano-triggers (NT), previously described in the literature, able to produce NO upon illumination, we designed and synthesized new generations of compounds potentially capable of initiating the catalytic activity of NOS under irradiation. They contain a recognition unit for NOS derived from adenosine and a diaminophenyl butadiene chromophoric moiety, linked together by a triazole group. These modular structures, easily assembled by "click" chemistry allowed the preparation of a library of nano-triggers, whose photophysical properties and stability under physiological conditions were evaluated. These new generations of compounds offer interesting perspectives for the control of biological processes by light.

Durante o processo inicial da reação de presa, o cimento de ionômero de vidro modificado por resina (CIVMR) apresenta baixo módulo de elasticidade, característica importante quando utilizado como base de restaurações com resina composta, por diminuir o estresse de contração de polimerização nas paredes cavitárias. O presente estudo teve como objetivo analisar a influência da técnica de polimerização de uma base CIVMR (VitrebondTM) por resina na interface dente/restauração de resina composta, através de teste de microtração e análise em microscopia confocal. Foram utilizados 30 dentes molares humanos hígidos extraídos, nos quais foram confeccionadas cavidades padronizadas em sua face oclusal (5mm de comprimento x 3mm de largura x 4,5mm profundidade). O sistema adesivo utilizado AdperTM Single Bond 2 foi marcado previamente com Rodamina B (0,16mg/ml), para possibilitar a análise em microscópio confocal. Os dentes foram divididos em 3 grupos: Grupo 1 (controle): base de CIVMR VitrebondTM + fotoativação + sistema adesivo + resina composta FiltekTM Z250; Grupo 2: base de CIVMR VitrebondTM + sistema adesivo + fotoativação por 30 segundos simultânea dos dois materiais + resina composta FiltekTM Z250; Grupo 3: base de CIVMR por resina VitrebondTM + tempo de espera de 60 segundos + fotoativação + sistema adesivo + resina composta FiltekTM Z250. Após a restauração, os dentes permaneceram em água deionizada em estufa a 37 ºC por 24 horas. Em seguida, foram seccionados com disco de diamante em fatias de aproximadamente 0,8mm no sentido vestíbulo-lingual. Uma fatia de cada dente foi separada aleatoriamente para análise da presença de fendas na interface dentina/resina composta em microscopia confocal. As demais fatias foram seccionadas para a confecção de palitos, para os testes de microtração. Os resultados de resistência de união foram submetidos à análise de variância a um critério ANOVA a 5% e teste de qui-quadrado para as variáveis de presença de fendas marginais e tipo de fratura resultante (p<0,05). Não houve diferença estatisticamente significante entre os três grupos (p=0,644) com relação à resistência adesiva e tipo de fratura, predominando a fratura do tipo adesiva para todos os grupos. Quanto à presença de fendas marginais internas, foi evidenciada sua presença nos grupos 2 e 3, sem diferença estatisticamente significante entre os três grupos testados (p=0,082). Conclui-se, portanto, que a técnica de polimerização da base de cimento de ionômero de vidro modificado por resina não influencia na resistência adesiva da interface dente/restauração de resina composta. / During the initial process of setting reaction, the resin-modified glass-ionomer cement (RMGIC) shows low modulus of elasticity, which is an important characteristic when RMGIC is used as a liner in resin composites restorations, because it decreases the polymerization shrinkage stress in cavity walls. The aim of this study was to analyze the influence of polymerization techniques of resin-modified glass-ionomer cement used as a liner on the adhesive interface dentin/resin by microtensile test and confocal microscopic analysis. Standardized occlusal cavity preparations (5mm length x 3mm wide x 4.5mm depth) were prepared in 30 human extracted molars. For the analysis at the confocal microscope, the adhesive system AdperTM Single Bond 2 was previously marked with rodhamine B (0.16mg/ml). The tooth were divided into three groups: Group 1 (control): RMGIC liner VitrebondTM + photoactivation for 30 seconds + adhesive system + resin composite Filtek TM Z250; Group 2: RMGICs liner VitrebondTM + adhesive system + simultaneous photoactivation of both materials + resin composite FiltekTM Z250; Group 3: RMGICs liner VitrebondTM+ 60 seconds delay time + photoativation for 30 seconds + adhesive system + resin composite FiltekTMZ250. Specimens were stored at 37ºC in deionized water for 24 hours. After this period, tooth was sectionated in 0.8mm slices (buco-lingual). One slice of each tooth was randomly selected for confocal microscopy for analysis of the interface resin/dentin. The other slices were sectionated in sticks (mesio-distal) for microtensile test. One-way ANOVA (p<0.05) showed no significant statistical difference among groups 1, 2 and 3 (p=0.644). Quisquare test showed no significant statistical difference of type of fracture (adhesive fracture was predominant) and presence of gap at the interface dentin/resin among groups. (p=0.082). It can be concluded, that polymerization technique of resin-modified glassionomer cement (RMGIC) did not influence bond strength and dentin/resin composite interface.

During recent decades metallic nanoparticles have been found very interesting due to their unique characteristics which make them suitable for different applications. In this research, for the very first time, we tried to perform selective surface photo activation chemistry on the targeted facets of nanoparticles while they are in suspension. This technique enabled us to form desired assemblies of nanoparticles. We focused on elongated shaped gold nanorod due to its unique surface plasmon resonance and probable biomedical applications. In this research we formed a dumbbell shape assembly of nanoparticles in suspension. A probable application for these assemblies can be in vivo imaging. Initially, we reproduced gold nanorods using existing techniques in prior papers and optimized them according to our research needs. A low rpm centrifugal separation technique was developed to efficiently separate synthesized gold nanorods from other shapes. Several characterization techniques were utilized to characterize nanoparticles at each step including UV-absorbance, zeta potential, and dynamic light scattering. Different generations of oligomers were synthesized to be used as gold nanorods coating, and each coating was tested and characterized using appropriate techniques. Our two-step coating replacement method using one of these photocleavable oligomers enabled us to achieve, for the very first time, selective UV photo activation of gold nanorod tips. The photo activated tips were then exposed to oppositely charged gold nanospheres to form dumbbell shape assemblies of gold nanorods and nanospheres. Furthermore, dumbbell shape assembly of nanoparticles was investigated and characterized. / Master of Science