Foram confeccionados corpos-de-prova para testar a resistência flexural (MF), para testar a sorção de água (Wsp) e material solúvel (Ws) em resina quimicamente ativada (RAAQ), baseados nas especificações no 12 da ADA e ISO 1567 utilizando matrizes especiais à temperatura de 37±1oC. Os espécimes foram preparados em contato com um papel contaminado ou não com 20 mg de eugenol e em cinco condições de tratamento superficial: controle (C), Vaselina (V), PanOxyl 10% (P), PanOxyl 10% + DMT (P10D) e PanOxyl 20% + DMT (P20D). Foram utilizados dois tipos de monômero: MMA, como fornecido pelo fabricante, e com EGDMA. O teste de resistência flexural foi aplicado aos 30 minutos ou com 50 horas a partir do início da mistura. A análise de Wsp e Ws foi aplicada sobre espécimes com 7 dias. A análise dos resultados mostrou que a presença do eugenol afetou a polimerização das RAAQ quando não se utilizou nenhum tratamento paliativo, resultando em queda significativa do módulo flexural aos 30 minutos, enquanto que para a idade de 50 horas, houve apenas uma tendência de diminuição dos valores de módulo flexural. O eugenol, provocou uma diminuição significativa da sorção de água, aumentando porém a solubilidade dos espécimes. Os tratamentos superficiais P10D e P20D aplicados durante a polimerização da resina, conseguiram reverter os efeitos negativos da presença do eugenol sobre o módulo flexural, independentemente da presença do agente de ligação cruzada no monômero. Nesses casos, a sorção de água e solubilização não são afetadas significativamente quando comparadas com os espécimes controle. O tratamento com vaselina provocou uma diminuição significativa do módulo flexural independentemente da idade ou presença de EGDMA, embora não tenha aumentado a sorção de água, nem a solubilidade da resina quando o EGDMA esteve presente. Na ausência de EGDMA, este tratamento aumentou a solubilidade. O tratamento P10 apresentou um comportamento pouco seguro, uma vez que não conseguiu anular os efeitos da presença do eugenol em todas as propriedades e situações estudadas, provocando ainda, uma queda significativa do módulo flexural na idade de 50 horas. / Specimens for flexural strength test (FS), water sorption test (Wsp) and soluble matter test (Ws) were built using a chemically-activated acrylic resin, according to ADA\'s no 12 and ISO 1567 specifications. Using a metallic mould under room temperature of 37±1oC, specimens were prepared with the mould placed on contaminated paper slab or not by 20 mg of eugenol. Five experimental conditions were tested: control (C), petrolatum (P), PanOxyl 10% (P10), PanOxyl 10% + DMT (P10D), PanOxyl 20% + DMT (P20D). Two types of monomer were tested: MMA as supplied by manufacturer and MMA + EGDMA. Flexural test was performed at 30 minutes or at 50 hours, after resin manipulation start. The Wsp and Ws analyses were performed after 7 days. The results showed that eugenol significantly reduced the FS at 30 minutes. At 50 hours, only a trend of decrease was found. The presence of eugenol reduced the water sorption and increased the solubility of the specimens. P10D and P20D applied during polymerization reverted the negative effect of eugenol on FS, regardless of the presence of the crosslinking agent. Wsp and Ws were not significantly altered. Petrolatum application reduced FS significantly, regardless of the storage time or the presence of EGDMA. Nevertheless when EGDMA was present, the petrolatum did not interfere with Wsp and Ws. In the absence of EGDMA, petrolatum increased resin solubility. Treatment with P10 was not reliable, because it was not effective for all the properties studied and, moreover, it led to a significant decrease in FS at 50 hours.

A resina acrílica encontra-se entre os materiais mais utilizados na odontologia. Apesar de suas qualidades, o polimetilmetacrilato ainda mostra-se um material com resistência comprometida. Para tanto, diversos reforços têm sido propostos na literatura e entre eles encontram-se as fibras de vidro e aramida. Apesar de acrescerem na resistência da matriz acrílica pouco se sabe sobre como os esforços aplicados sobre a resina reforçada por fibras são transmitidos e distribuídos às áreas de sustentação, o que motivou a realização deste estudo. Foram confeccionados dez corpos-de-prova em resina acrílica termopolimerizável divididos em cinco grupos segundo o reforço utilizado: fibras de vidro filamentares tratadas por imersão no monômero acrílico (Grupo F), fibras de vidro em malha submetidas ao mesmo tratamento (Grupo M), fibras de vidro trançadas com aramida e tratadas por imersão na mistura monômero/polímero (Grupo H) e fibras de vidro trançadas com aramida e tratadas por silanização (Grupo HS). Como grupo controle (C) foram utilizadas amostras de resina acrílica termicamente ativada sem a associação de fibras de reforço. Após a adaptação dos corpos-de-prova à matriz fotoelástica os mesmos foram submetidos a ensaio de flexão através da Máquina Universal de Ensaios (EMIC-modelo DL 2000, S. J. dos Pinhais, PR, Brasil) acoplada ao Polariscópio Circular (Desenvolvido na Faculdade de Engenharia Mecânica - UFU, Uberlândia, MG, Brasil). Os resultados mostraram valores para a Energia de Distorção, em Kgf/mm2, de 223,124 para o grupo F; de 218,710 para o grupo H; 217,692 para o grupo M; 215,810 para o grupo HS e de 210,122 para o grupo C. Também foi observado que a energia de distorção apresentou distribuição homogeneamente crescente em todos os grupos estudados. Concluímos que a associação de fibras à resina acrílica gerou aumento da energia acumulada na área de sustentação protética sendo que os maiores valores foram observados para o grupo de fibras de vidro filamentares. Observamos também que a silanização da fibra híbrida contribuiu para uma menor transmissão de tensão à matriz fotoelástica. / Acrylic resin is found among the most used materials in dentistry. Despite its qualities, the polymetilmetacrylate yet shows itself as a material with questionable resistance. Therefore, lots of reinforcements have been proposed in literature and among them we find glass fibers and aramid. Although they add to the resistance of the acrylic matrix, little is known about how the efforts applied upon the resin strengthened by the fibers are transmitted and distributed over the sustaining areas, which motivated the course of this study. Ten specimens made of termcured acrylic resin were created and divided into five groups according to the reinforcement used: roving glass fibers treated by immersion in the acrylic monomer (Group F), mesh glass fibers given the same treatment above (Group M), glass fibers braided with aramid and treated by immersion in the blending momer/polimer (Group H) and glass fibers braided with aramid and treated by signalization (Group HS). As control group (C) were used samples of acrylic resin termically activated without the addition of fibers. After adapting the specimens to the photoelastic matrix, the former were submitted to flexural tests through the Universal Machine of Rehearsal (EMIC-model DL 2000, S. J. Dos Pinhais, PR, Brazil) joint to the Circular Polariscope ( developed in the Mechanical Engineering College ? UFU, Uberlândia, MG, Brazil. The results show values to the Distortion Energy, in Kgf /mm2, of 223,124 for group F; 218,710 for group H; 217,692 for group M; 215,810 for group HS and 210,122 for group C. It was also observed that the distortion energy presented homogeneous growing distribution in al the groups studied. We conclude that the association of fibers to the acrylic resin generated an increase of the energy accumulated in the area of prosthetic support, thus the highest values were observed in the group with roving glass fibers. We noticed that the silanization of the hibrid fiber contributed to a smaller tension transmission to the photoelastic matrix.

Orientador: Marco Antonio Compagnoni / Banca: Débora Barros Barbosa / Banca: Lucimar Falavinha Vieira / Resumo: O objetivo do presente trabalho foi avaliar a porosidade em bases de resina acrílica de prótese total maxilar, processadas em diferentes ciclos de polimerização e confeccionadas em três espessuras (2,0, 3,5 e 5,0 mm). Cinco grupos foram estabelecidos, de acordo com os ciclos de polimerização: A) Onda-Cryl, ciclo curto em microondas; B) Onda-Cryl, ciclo longo em microondas; C) Onda-Cryl, ciclo do fabricante; T) Clássico, banho de água; Q) Jet, ciclo em câmara de pressão. Após o seu processamento, as bases de resina acrílica foram pesadas em ar e em água e a porcentagem de porosidade foi relacionada com a absorção de água no interior desse material. Os dados de % de porosidade foram submetidos ao teste de Kruskal-Wallis para a comparação entre os grupos (a= 5%). Dentro das limitações do presente estudo, concluiu-se que os ciclos de polimerização e a espessura do espécime de resina acrílica têm influência na porosidade, já que diferenças estatisticamente significantes foram encontradas entre os ciclos e espessuras avaliados. Não houve diferença de porosidade entre as bases de resina polimerizadas no ciclo T para qualquer uma das espessuras. / Abstract: The aim of this study was to evaluate the porosity on (acrylic resin) maxilar complete denture bases, processed through diferent polimerization cycles, procedure done in three different kinds of thickness (2,0, 3,5 e 5,0 mm). Five groups were proposed, according to the polimerization cycles: A) Onda-Cryl, short microwave cycle; B) Onda-Cryl, long microwave cycle; C) Onda-Cryl, manufacturing microwave cycle; T) Clássico, water bath; Q) Jet, press chamber cycle. After the process, the denture bases were weighted in air and in water, and the percent of porosity was related to the water absorption within this material. The porosityþs % data were submitted to the Kruskal-Wallis test to promote the comparison among the groups. In despite of the present paperþs limitations, we have concluded that the polimerization cycles and the specimenþs thickness of acrylic resin really influence the porosity. This result was reached because statistically significant differences were found in the cycles and thickness evaluated. It has been not observed porosity differences in the polimerized resin bases in T cycle in relation to any thickness. / Mestre

Universidade Federal do Cearà / A possÃvel presenÃa de microorganismos potencialmente patogÃnicos em prÃteses dentÃrias recÃm-chegadas dos laboratÃrios protÃticos deve ser considerada. Este estudo avaliou o nÃvel de contaminaÃÃo bacteriana e fÃngica de espÃcimes de resina acrÃlica confeccionados em 14 laboratÃrios de prÃtese dentÃria, inscritos no Conselho Regional de Odontologia do CearÃ, na cidade de Fortaleza. Cada laboratÃrio foi solicitado a confeccionar 10 espÃcimes de resina acrÃlica, a partir de modelos padronizados de silicona de adiÃÃo estÃreis, desconhecendo os objetivos da pesquisa. Os espÃcimes recebidos dos laboratÃrios foram colocados em tubos individuais contendo BHI caldo e incubados a 37ÂC por 48 horas e, em seguida, removidos, lavados, colocados em soluÃÃo salina estÃril e agitados para desprendimento microbiano. A suspensÃo obtida foi diluÃda em 1:100, 1:1000 e semeada em placas com Ãgar Sangue, Sabouraud Dextrose Ãgar e HICrome UTI ÃgarÂ, para incubaÃÃo por 48 horas a 37ÂC. Foi obtido o nÃmero de unidades formadoras de colÃnias (UFC) bacterianas e fÃngicas viÃveis, alÃm da identificaÃÃo e quantificaÃÃo de algumas espÃcies de bactÃrias, comparando-se os laboratÃrios por meio dos testes de Kruskall-Wallis e Dunn (&#945;=0.05). Houve contaminaÃÃo advinda de todos os laboratÃrios analizados, com uma contagem de UFC mÃdia de 101438 de bactÃrias e 71047 de fungos. Pseudomonas spp foi o microorganismo a mais prevalente identificado (p<0,05). Foi concluido que existe risco de contaminaÃÃo por bactÃrias potencialmente patogÃnicas e fungos em dispositivos protÃticos recÃm chegados dos laboratÃrios. / The possible presence of potentially pathogenic microorganisms in denture newly arrived from prosthetic laboratories should be considered. This study evaluated the level of bacterial and fungal contamination of specimens of acrylic resin made in 14 dental laboratories registered with the Regional Council of Dentistry of CearÃ, Fortaleza. Each laboratory was asked to fabricate 10 specimens of acrylic resin, from standard models of sterile silicone addition, unaware of the research objectives. Specimens received from laboratories were placed in individual tubes containing BHI broth, incubated at 37ÂC for 48 hours and then removed, washed and placed in sterile saline and stirred for microbial detachment. The suspension obtained was diluted (1:100, 1:1000) and plated on blood agar plates, and Sabouraud Dextrose Agar and Agar HiCrome ICU by incubation for 48 hours at 37ÂC. The number of colony forming units (CFU) bacterial and fungal viable was obtained, besides the identification and quantification of some species of bacteria, comparing the laboratory by means of the Kruskal-Wallis and Dunn (&#945; = 0.05) tests. There was contamination originating from all laboratories analyzed, with a mean CFU counts of 101438 bacteria and 71047 fungi. Pseudomonas spp was the most prevalent microorganism identified (p < 0.05). It was concluded that there is a risk of contamination with potentially pathogenic bacteria and fungi in prosthetic devices newly arrived from dental laboratories.

Foram confeccionados corpos-de-prova para testar a resistência flexural (MF), para testar a sorção de água (Wsp) e material solúvel (Ws) em resina quimicamente ativada (RAAQ), baseados nas especificações no 12 da ADA e ISO 1567 utilizando matrizes especiais à temperatura de 37±1oC. Os espécimes foram preparados em contato com um papel contaminado ou não com 20 mg de eugenol e em cinco condições de tratamento superficial: controle (C), Vaselina (V), PanOxyl 10% (P), PanOxyl 10% + DMT (P10D) e PanOxyl 20% + DMT (P20D). Foram utilizados dois tipos de monômero: MMA, como fornecido pelo fabricante, e com EGDMA. O teste de resistência flexural foi aplicado aos 30 minutos ou com 50 horas a partir do início da mistura. A análise de Wsp e Ws foi aplicada sobre espécimes com 7 dias. A análise dos resultados mostrou que a presença do eugenol afetou a polimerização das RAAQ quando não se utilizou nenhum tratamento paliativo, resultando em queda significativa do módulo flexural aos 30 minutos, enquanto que para a idade de 50 horas, houve apenas uma tendência de diminuição dos valores de módulo flexural. O eugenol, provocou uma diminuição significativa da sorção de água, aumentando porém a solubilidade dos espécimes. Os tratamentos superficiais P10D e P20D aplicados durante a polimerização da resina, conseguiram reverter os efeitos negativos da presença do eugenol sobre o módulo flexural, independentemente da presença do agente de ligação cruzada no monômero. Nesses casos, a sorção de água e solubilização não são afetadas significativamente quando comparadas com os espécimes controle. O tratamento com vaselina provocou uma diminuição significativa do módulo flexural independentemente da idade ou presença de EGDMA, embora não tenha aumentado a sorção de água, nem a solubilidade da resina quando o EGDMA esteve presente. Na ausência de EGDMA, este tratamento aumentou a solubilidade. O tratamento P10 apresentou um comportamento pouco seguro, uma vez que não conseguiu anular os efeitos da presença do eugenol em todas as propriedades e situações estudadas, provocando ainda, uma queda significativa do módulo flexural na idade de 50 horas. / Specimens for flexural strength test (FS), water sorption test (Wsp) and soluble matter test (Ws) were built using a chemically-activated acrylic resin, according to ADA\'s no 12 and ISO 1567 specifications. Using a metallic mould under room temperature of 37±1oC, specimens were prepared with the mould placed on contaminated paper slab or not by 20 mg of eugenol. Five experimental conditions were tested: control (C), petrolatum (P), PanOxyl 10% (P10), PanOxyl 10% + DMT (P10D), PanOxyl 20% + DMT (P20D). Two types of monomer were tested: MMA as supplied by manufacturer and MMA + EGDMA. Flexural test was performed at 30 minutes or at 50 hours, after resin manipulation start. The Wsp and Ws analyses were performed after 7 days. The results showed that eugenol significantly reduced the FS at 30 minutes. At 50 hours, only a trend of decrease was found. The presence of eugenol reduced the water sorption and increased the solubility of the specimens. P10D and P20D applied during polymerization reverted the negative effect of eugenol on FS, regardless of the presence of the crosslinking agent. Wsp and Ws were not significantly altered. Petrolatum application reduced FS significantly, regardless of the storage time or the presence of EGDMA. Nevertheless when EGDMA was present, the petrolatum did not interfere with Wsp and Ws. In the absence of EGDMA, petrolatum increased resin solubility. Treatment with P10 was not reliable, because it was not effective for all the properties studied and, moreover, it led to a significant decrease in FS at 50 hours.

Tunable nanostructures have many important uses in thin film applications. Tunability can be achieved by creating a film that has features that respond to external stimuli, such as temperature, humidity, or pH. However, the response can vary greatly between a confined and unconfined case. In the case of confined materials, this response can be greatly reduced, even completely suppressed, which indicates that separate studies must be conducted on confined states in order to better understand their use for real applications. Microgels have been previously shown to have exceptional responsive properties that depend on their chemical structure and synthesis. Unlike solid thin hydrogel films that respond on the order of hours, microgels arrange on a surface with no external force and create a highly porous layer which responds rapidly, on the order of minutes, to outside stimuli. These properties make microgels a promising candidate for use in tunable thin films. Although the responsive properties of microgels have been extensively studied in solution and unconfined films, this is not indicative of conditions that would most likely have the microgels placed between two stiffer layers of material. Microgels have been shown to respond to glucose concentration, temperature, pH, and light. One well-studied microgel is poly-N-isopropylacrylamide copolymerized with Acrylic Acid (pNIPAM-co-AAC). These microgels use the thermal response of pNIPAM combined with the pH sensitivity of pAAC to create a dually-responsive material. To study the effects of confinement on pNIPAM-co-AAC microgels, we encapsulated these particles within bi-layers of poly(allylamine hydrochloride)-poly(sodium 4-styrenesulfonate) (PAH-PSS) in order to simulate their response within a polyelectrolyte material. Our samples were prepared with a method called tilt-drying, which creates a microgel concentration gradient. This allowed us to study both the confinement caused by the multi-layered film as well as the effects of microgels on each other. Our results have shown that the change in particle height is unaffected by the concentration of the film, but the thermal response of pNIPAM-co-AAC microgels is significantly suppressed by the encapsulation of microgels into nanoscale layers.

Baigiamajame darbe suteikti įspūdį, kuris išreiškiamas per spalvas, dėmes, šešėlius ir judesį. Baigiamojo darbo atlikimo technika yra gana nauja, nes tokio tipo darbų nėra. Ieškant pavyzdžių, jų nebuvo rasta. Technika buvo atrasta remiantis bandomųjų darbų eskizais. Pasirinkus pastozinę tapybą, galima nutapyti įvairias temas išreiškiant jas abstrakcijomis, judesiu, spalvomis. Abstrakcija prasideda nuo tikrovės, kuri apkarpoma atsikratant pertekliaus, ir galiausiai atsiskleidžia vertinga, dažnai netikėta esmė, sukuriamas minimalus žodynas, perteikiantis kuo daugiau pojūčių ir jausmų. / To create an impression witch is expressed by colors, splashes, shadows and movements. The technique of my bachelor is quite new, because there aren’t such types of works. In searching such works it was not found. This technique was found with reference to experimental sketch of work. In selecting the postoso action painting is possible to paint various themes expressing it with abstractions, movements, colors. The abstraction starts from reality which get a rid of abundance and ultimately dehisce valuable, frequently unexpected essentiality. Is creating a minimal vocabulary witch convey more sensations and sensibilities.

Controlled free radical polymerization facilitates the production of polymers with highly defined microstructures like traditional ionic polymerization; but in contrast allows for previously unattainable monomer combinations such as acrylic acid in its non-protected form. Incorporation of acrylic acid into styrene was done by random copolymerization of acrylic acid (directly and in its protected form as tert-butyl acrylate) with styrene. Styrene/tert-butyl acrylate (S/t-BuA) as well as styrene/acrylic acid (S/AA) mixtures were copolymerized to form tapered or gradient copolymers. Using an alkoxyamine unimolecular initiator, 2-[N- tert-butyl-2,2-(dimethylpropyl)aminooxy] propionic acid (BlocBuilder RTM), along with additional free nitroxide (SG1), the effect of acid protection on polymerization kinetics and copolymer composition was determined. Adding 4.5 mol% SG1/BlocBuilderRTM greatly improved the control of S/t-BuA copolymerization with low polydispersities (1.14-1.22) whereas the S/AA required higher levels of SG1 to produce polymers with low polydispersities that were comparatively still broader compared to the S/t-BuA system (polydispersities &sim; 1.3-1.4 at 9 mol% SG1/BlocBuilderRTM). S/AA copolymerization required higher SG1 concentrations to compensate for degradation of SG1 by attack from the acrylic acid monomer.

It was demonstrated for the first time that RAFT polymerizations of NIPAAm can be carried out directly in water at room temperature without photo initiator under UV radiation. Under these conditions, the controlled/living features could be proven for a large range of monomer/RAFT agent ratios. Moreover, even at a monomer conversion exceeding 80%, polymerization control (PDI<1.2) is maintained. It is also demonstrated that the RAFT polymerization of AA can be carried out without photo initiator in water at ambient temperature in the presence of TRITT at short wavelength. At these wavelengths, the controlled/ living characteristics is maintained even at a monomer to polymer conversions exceeding 80%. UV/Vis spectrometry was employed to monitor the functional group (-S(C=S)S-) changes of the employed trithiocarbonate RAFT agent S,S???-Bis(??,?????-dimethyl-acetic acid)-trithiocarbonate (TRITT) in aqueous solution when exposed to UV radiation. It is shown that the degradation pattern of TRITT alone as well as TRITT in the presence of NIPAAm deviate from each other. Surprisingly, it is found that TRITT completely decomposed at 254 nm while the addition of monomer prevented the decomposition of TRITT at the same wavelength. Nuclear magnetic resonance (NMR) techniques were applied to study the decomposition products of TRITT in solution without the addition of monomer. Methanol-d4 was selected as the solvent. In addition, high-resolution soft ionization mass spectrometry techniques were used to map the product species generated during UV radiation induced RAFT polymerizations of NIPAAm and AA in aqueous media, allowing for the tentative assignment of end groups. The NMR analysis suggests that the decomposition of TRITT in methanol-d4 under UV radiation has three cleavage patterns. These three cleavage patterns (described in the current thesis in detail) all occur at the ???S(C=S)S- group, which is the weakest structural unit in TRITT molecule. iii However, polymerization occurs prior to decomposition, if monomer is present. The mass spectrometric analysis suggests that the initial radicals result from the dissociation of TRITT, as well as monomer. Trithiocarbonate end group degradation leading to the formation of thiol terminated chains is also occurring. In the case of NIPAAm polymerization, a peak which may be associated with a cross termination product of the intermediate radical was observed under both 302 nm and 254 nm wavelength irradiation. Interestingly, this peak does not occur in AA polymerization at any wavelength (nor is it expected to form under conventional RAFT conditions and was not observed in previous mass spectrometry studies in thermal or ??-initiated polymerizations of NIPPAm with TRITT) and thus this assignment should be treated as very tentative only.

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.