Purpose: To determine microleakage and microtensile bond strength (µTBS) of composite restorations bonded with self-adhesive resin-cements. Methods: Six groups of molars were assigned to cements: RelyX-Unicem, Breeze, Monocem, PanaviaF-2.0, Filtek-LS, and Scotch-Bond-Multipurpose (adhesive). For microleakage, Class II preparations were made. Cements were applied onto all cavity walls. Preparations were restored, specimens themocycled and then immersed in red dye. Dye penetration was assessed according to 5-point scale. For µTBS test, 6 mm composite buildups were made over tooth surfaces. Rectangular rods were cut and subjected to tensile force. Mean µTBS and SDs were calculated. Results: RelyX-Unicem and Breeze showed low microleakage, however, they had lower µTBS values. Filtek-LS showed the least microleakage and the highest µTBS with dentin. Conclusion: RelyX-Unicem, Breeze and Filtek-LS will improve marginal seal when used in subgingival Class II composite restorations.

Purpose: To determine microleakage and microtensile bond strength (µTBS) of composite restorations bonded with self-adhesive resin-cements. Methods: Six groups of molars were assigned to cements: RelyX-Unicem, Breeze, Monocem, PanaviaF-2.0, Filtek-LS, and Scotch-Bond-Multipurpose (adhesive). For microleakage, Class II preparations were made. Cements were applied onto all cavity walls. Preparations were restored, specimens themocycled and then immersed in red dye. Dye penetration was assessed according to 5-point scale. For µTBS test, 6 mm composite buildups were made over tooth surfaces. Rectangular rods were cut and subjected to tensile force. Mean µTBS and SDs were calculated. Results: RelyX-Unicem and Breeze showed low microleakage, however, they had lower µTBS values. Filtek-LS showed the least microleakage and the highest µTBS with dentin. Conclusion: RelyX-Unicem, Breeze and Filtek-LS will improve marginal seal when used in subgingival Class II composite restorations.

Bis-GMA-containing resin-composites undergo biodegradation by human saliva derived esterases, yielding Bis-hydroxy-propoxy-phenyl-propane (Bis-HPPP). The hypothesis of this study is that the exposure of dental restorations to saliva-like esterase activities accelerates marginal bacterial microleakage. Resin-composites (Scotchbond, Z250, 3M) bonded to human dentin were incubated in either buffer, or dual-esterase media (pseudocholinesterase/cholesterol-esterase; PCE-CE) with activity levels simulating that of human saliva, for up to 90 days. Incubation solutions were analyzed for resin degradation by-products using high-performance liquid-chromatography. Post-incubation, specimens were suspended in a chemostat-based biofilm fermentor cultivating Streptococcus mutans NG8 for 7 days. Bacterial microleakage was assessed by confocal laser scanning microscopy. Bis-HPPP production, as well as depth and spatial volume of bacterial cell penetration within the interface increased with incubation time. Biodegradation and bacterial microleakage were significantly higher for 30 and 90 day PCE-CE vs. buffer incubated groups (p<0.05). Conclusion: An overall decline in interfacial integrity was observed following exposure to human saliva-like esterases over time.

Bis-GMA-containing resin-composites undergo biodegradation by human saliva derived esterases, yielding Bis-hydroxy-propoxy-phenyl-propane (Bis-HPPP). The hypothesis of this study is that the exposure of dental restorations to saliva-like esterase activities accelerates marginal bacterial microleakage. Resin-composites (Scotchbond, Z250, 3M) bonded to human dentin were incubated in either buffer, or dual-esterase media (pseudocholinesterase/cholesterol-esterase; PCE-CE) with activity levels simulating that of human saliva, for up to 90 days. Incubation solutions were analyzed for resin degradation by-products using high-performance liquid-chromatography. Post-incubation, specimens were suspended in a chemostat-based biofilm fermentor cultivating Streptococcus mutans NG8 for 7 days. Bacterial microleakage was assessed by confocal laser scanning microscopy. Bis-HPPP production, as well as depth and spatial volume of bacterial cell penetration within the interface increased with incubation time. Biodegradation and bacterial microleakage were significantly higher for 30 and 90 day PCE-CE vs. buffer incubated groups (p<0.05). Conclusion: An overall decline in interfacial integrity was observed following exposure to human saliva-like esterases over time.

Self-etching dentine bonding agents are a recent addition to the choice of bonding agents which a clinician has available to bond resin restorations to tooth structure. The so-called ‘traditional’, total-etch fourth and fifth generation dentine bonding agents have proven their clinical abilities and the question now remains whether these ‘new’ self-etching dentine bonding agents will clinically perform as well as the ‘proven’ total-etch dentine bonding agents. For the purpose of this dissertation the author completed three research projects which were performed to evaluate the efficacy of a selection of dentine bonding agents and then used the results to compare some properties (shear bond strength, microleakage, and anti-bacterial properties) of total-etch dentine bonding agents with some self-etching dentine bonding agents. All discussions will focus on the three dentine bonding agent properties evaluated by the three research projects performed. The three specific aims of this study were: <ul> <li> To compare the dentine shear bond strength of a selection of self-etching dentine bonding agents with that of a total-etch dentine bonding agent control.</li> <li> To compare dentine and enamel microleakage values of a selection of self-etching bonding agents with that of a total-etch dentine bonding agent control.</li> <li> To evaluate the possible anti-bacterial properties of a selection of dentine bonding agents, with focus placed on the self-etching dentine bonding agent ABFb (Clearfil Protect Bond).</li></ul> The studies performed by the author achieved comparative/similar results to some studies described in the literature but it is clear from the literature that some studies provide conflicting results, especially leakage of enamel margins when using self-etching bonding agents. Taking into consideration the limitations of the three studies performed, it can be concluded that as far as the three evaluated properties of self-etching dentine bonding agents are concerned, they should prove to be acceptable clinical alternatives for use in place of total-etch dentine bonding agents. Copyright / Dissertation (MSc(Odont))--University of Pretoria, 2010. / Odontology / unrestricted

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A finalidade deste estudo foi avaliar “in vitro" a microinfiltração marginal presente na interface da parede gengival de cavidades classe II em molares decíduos, restaurados com resina composta (auto e fotopolimerizável), com a utilização de uma solução corante. Os preparos cavitários apresentavam a parede gengival em esmalte, sendo restaurados segundo 4 diferentes técnicas: resina composta fotopolimerizável; resina composta autopolimerizável; técnica mista (resina composta auto e fotopolimerizável) e ionômero de vidro/resina composta. Em seguida, procedeu-se à ciclagem térmica (5oC e 55oC, 700 ciclos), impermeabilização, imersão em solução corante e seccionamento. A avaliação quanto à microinfiltração, foi feita seguindo-se uma escala preestabelecida (graus de 0 a 4). Após a análise estatística dos resultados, concluiu-se que todos os grupos apresentaram microinfiltração, em graus variados, todavia os grupos que utilizaram a técnica mista e o ionômero/resina fotopolimerizável apresentaram os menores graus de infiltração, e que não se observou microinfiltração na interface resina composta autopolimerizável/fotopolimerizável. / The purpose of this study was evaluation “in vitro" of marginal microleakings, present on gum’s edges of class II cavities of deciduous molars, restored with composite resin (auto and light-cured), with the use of a staining solution to verify the leaking. Cavities prepared presented enamel on gum’s edges and were restored according to four different techniques: lightcured composite resin; auto-cured composite resin; mixed technique (auto and light-cured composite resin) and glass-ionomer/composite resin. Next, we proceeded to thermo-cycling (5°C and 55°C, 700 cycles), turning impermeable, immersion in staining solution and slicing. The microleaking evaluation was done according to a pre-established scale (from 0 a 4 degrees). After the statical analysis of the results, it was concluded that all the groups presented microleaking, in varying degrees. However, the groups which used the mixed technique and light-cured resin presented the smallest levels of leaking, and microleaking was not observed on the auto-cured composite resin/light-cured composite resin edge.

O objetivo deste trabalho foi avaliar a microinfiltração de restaurações classe V em preparos de cavidades obtidos com diferentes potências do laser Er;Cr:YSGG e as cavidades preparadas convencionalmente (ponta diamantada em alta rotação). Sessenta amostras de dentina foram divididas em seis grupos (n = 10). O primeiro grupo serviu como um controle padronizado com preparo de ponta diamantada (G1), os demais grupos foram irradiados com laser de Er;Cr:YSGG com diferentes parâmetros: G2- 2,0W; G3- 2,25W; G4- 2,5W; G5- 2,75W; G6- 3,0W. Este laser emite comprimento de onda de 2,78m e tem largura de pulso de 140m e taxa de repetição fixa de 20Hz. A energia do laser foi entregue através de um sistema de fibra óptica para um terminal de ponta de safira de 6mm de comprimento e 600m de diâmetro, utilizando modo não contato. O sistema adesivo autocondicionante (Clearfil SE Bond- Kuraray, Japan) e a resina composta microhíbrida (Z-250, 3M/ESPE, St.Paul, USA) foram utilizados para compor os corpos de prova. Após as restaurações, os espécimes foram submetidos a teste de microinfiltração com solução de azul de metileno a 2% em pH 7,0, durante 4 horas, a 37°C. Os resultados mostraram não haver di ferença estatística (p=0,203) entre os grupos experimentais em que os preparos das cavidades foram realizados com ponta diamantada ou com diferentes parâmetros de energia do laser de Er;Cr:YSGG. A partir do presente estudo, pode-se concluir que a microinfiltração foi semelhante em todos os grupos experimentais independente do método de preparo cavitário de classe V usado - laser Er;Cr:YSGG ou ponta diamantada. / The aim of this work was to evaluate dye penetration of Class V restorations in cavity preparations obtained with different power setting of an Er;Cr:YSGG laser or with diamond bur and high-speed handpiece. Sixty samples of dentin were divided into six groups (n=10). The first group served as a control with standardized diamond bur cut (G1); the other groups were irradiated with an Er;Cr:YSGG laser with different power parameters: G2- 2.0W; G3- 2.25W; G4- 2.5W; G5- 2.75W; G6- 3.0W. This laser emitting at a wavelength of 2.78m and had pulse duration of 140m and fixed pulse repetition rate of 20Hz. Laser energy was delivered through a fiberoptic system to a sapphire tip terminal 6mm long and 600m in diameter, using non-contact mode. Self-etching adhesive system (Clearfil SE Bond- Kuraray, Japan) and microhybrid composite resin (Z-250, 3M/ESPE, St. Paul, USA) were used to compose the samples. After restoration, specimens were submitted to a microleakage test with 2% methylene blue solution at pH 7.0, for 4 h at 37°C. Results showed no statistical difference (p=0.203) between experimental groups in which cavity preparations were performed by diamond bur or different power settings of Er;Cr:YSGG laser. From the present study, it can be concluded that microleakage were similar to all experimental groups irrespective of the Class V cavity preparation method used - Er;Cr:YSGG laser system or diamond bur.

O objetivo do presente trabalho foi avaliar o grau de conversão, bem como o padrão de microinfiltração, de uma resina composta frente às seguintes variações nas condições de fotopolimerização: intensidade de luz X tempo e distância fonte de luz-superfície do compósito. Espécimes cilíndricas do material Esthet-X A2 (5mm de diâmetro e 2mm de altura) foram polimerizadas de acordo com os seguintes parâmetros: 600mW/cm2 por 40s, 400mW/cm2 por 60s ou 200mW/cm2 por 20s + 500mW/cm2 por 40s; distância fonte-resina de 0, 3 ou 7mm, resultando em nove grupos experimentais (n=3). A densidade de energia (intensidade X tempo) para todos os grupos foi de 24J/cm 2 . Os corpos de prova foram então submetidos à análise através do espectrofotômetro FT-Raman (RFS 100/S, Bruker; resolução de 4 cm -1 e 64 scans) para o cálculo da quantidade de duplas ligações remanescentes no material, tanto da face irradiada (FI) como da não-irradiada (FNI). A razão entre os picos relativos às bandas de 1610 e 1640 cm -1 (duplas ligações aromáticas e alifáticas, respectivamente) foi utilizada para estimar o grau de conversão. A análise estatística (ANOVA, com a<0,05, e teste de Tukey) mostrou significância dos fatores distância da fonte, face analisada e da interação modo de irradiação X distância. As médias de grau de conversão (em%) para 600, 400 e 200+500mW/cm2 foram respectivamente de 58,29 (±2,87); 57,99 (±2,94) e 58,32 (±2,46). Para as distâncias de 0, 3 e 7mm os valores obtidos foram: 59, 13 (±2,32); 58,61 (±3,08) e 56,85 (±2,24). As faces irradiadas apresentaram grau de conversão médio de 59,01 (±2,56) enquanto as não irradiadas de 57,40 (±2,67). Para o teste de microinfiltração, cavidades classe V foram confeccionadas em 90 incisivos bovinos. O substrato foi condicionado com ácido fosfórico a 37% durante 15 segundos, lavado e seco para a remoção do excesso de água, deixando-se, entretanto, a dentina úmida. Foi então aplicado o sistema adesivo Prime & Bond NT (Dentsply/Caulk). O preenchimento da cavidade foi feito em um só incremento, seguindo o mesmo padrão de polimerização proposto para o estudo do grau de conversão. Após a restauração, os dentes foram ar mazenados e então submetidos ao protocolo de teste com nitrato de prata. Foi utilizado para a análise dos escores de microinfiltração o teste de Kruskal -Wallis, não-paramétrico. Assim, foi observado que o modo de irradiação em dois passos causou uma diminuição na microinfiltração; tal redução também foi observada com o aumento da distância fonte de luz-compósito, com exceção dos grupos irradiados com 400mW/cm2. As médias dos escores de microinfiltração variaram entre 0,25 (±0,17) para o grupo com irradiação em dois passos, 7mm de distância e 2,0 (±0,96) para o grupo de 600mW/cm, 0mm. Não houve correlação entre grau de conversão e microinfiltração, bem como não houve influência da densidade de energia sobre esses testes. Por outro lado, pode-se concluir que a forma de fornecimento da energia na fotoativação correlaciona-se com a conversão e a microinfiltração. / The aim of this study was to assess the degree of conversion and microleakage of a restorative composite in relation to the following variations on the photoactivation conditions: light intensity x exposure time and distance from the light source. Degree of conversion was analyzed on cylindrical specimens (5 mm in diameter and 2 mm in height), photoactivated according to one of the following methods: 600mW/cm 2 x 40s; 400 mW/cm 2 x 60 s or 200 mW/cm 2 x 20s, followed by 500 mW/cm 2 x 40s. The distance from the light source was also variable: 0, 3 or 7 mm. Therefore, nine experimental groups (n=3) were obtained. Energy density (power density x exposure time) for all groups was kept constant (24 J/cm 2 ). Specimens were then submitted to FT-Raman analyses (RFS 100/S, Burker, 4cm -1 , 64 scans) for remaining double-bonds estimative, both on the top and on the bottom surfaces. The relation between 1610 and 1640 cm -1 peaks (aromathic and aliphatic bonds, respectively) was taken into account. Statistical analyses (ANOVA and Tukey test, a=0,05) found significance for the distance from the light source, the surface considered and the interaction between photoactivation mode and distance from the light source. Degree of conversion (in %) was 58,29 (±2,87), 57,99 (±2,94) and 58,32 (±2,46) for 600, 400 and 200+500 mW/cm 2 , respectively. For source distances of 0, 3 and 7 mm, values were 59,13 (±2,32) , 58,61 (±3,08) and 56,85 (±2,24), respectively. Top surfaces showed degree of conversion of 59,01 (±2,56), while for the bottom surface it was 57,40 (±2,67). For the microleakage test, the same composite was used for the restoration of class V cavities, made in 90 bovine incisors. The substrate was conditioned for 15 s with phosphoric acid (37%), then rinsed and gently dried. Prime & Bond NT (Dentsply/ Caulk) was then applied, according to the manufacturer’s instructions. Preparations were restored in bulk and photoactivated according to the procedures described for the degree of conversion analyses. The teeth were then stored for 24 in distilled water (37ºC) before being submitted to the silver-nitrate microleakage protocol. The results were analyzed using scores, submitted to the Kruskall-Wallis test. It could be observed that the two-step irradiation mode lead to less microleakage, when compared to the continuous modes. With exception to the specimens irradiated with 400mW/cm 2 , higher microleakage was observed for smaller distances from the light source. Means for the microleakage scores ranged from 0,25 (±0,17) for the two-step groups, 7mm from the light source to 2,0 (±0,96) for 600mW/cm 2 , 0mm. Power density did not influence neither the degree of conversion nor the microleakage. It could be concluded that photoactivation mode has an influence on the degree of conversion and on the microleakage.

A infiltração de fluido e bactérias nos espaços internos dos implantes foi observada em pilares intermediários parafusados, tanto em situações in vitro quanto in vivo devido à microfenda existente entre o implante e o pilar intermediário. Esse fato pode estar relacionado com a inflamação dos tecidos periimplantares e também com a produção de mau odor. O objetivo do presente estudo in vitro foi avaliar e comparar a ocorrência de infiltração de fluidos pela interface implante-pilar intermediário em três sistemas de implante com conexão do tipo cone Morse, e a capacidade de vedação de um adesivo anaeróbico, utilizando o radioisótopo Tecnécio-99m como marcador. Na primeira etapa, dez conjuntos implante-pilar intermediário de cada sistema foram imersos em solução contendo esse marcador, após a aplicação do torque recomendado pelo fabricante, e foram mantidos em pressão constante de 2 atm por um minuto. Na segunda etapa, um adesivo anaeróbico foi aplicado no pilar intermediário antes do mesmo ser parafusado ao seu respectivo implante. Após a aplicação da pressão, o infiltrado presente no interior dos implantes foi coletado com pontas de papel. Esse material foi depositado em tubos de ensaio para posterior leitura da radioatividade presente. A infiltração de fluido pela interface implante-pilar intermediário mostrou ser um fenômeno mensurável em todas as amostras dos três sistemas de implante com conexão do tipo cone Morse testados. A quantidade de infiltrado variou entre os sistemas e entre as amostras. A inconstância das amostras foi observada em todos os sistemas, no entanto, foi observado que o valor de infiltrado encontrado no Grupo 1 foi significantemente maior (p<0,05) do que o encontrado no Grupo 2, e não houve diferença estatística significante entre os Grupos 1 e 3, e entre os Grupos 2 e 3. Também foi observado que, com o uso do adesivo anaeróbico, os sistemas apresentaram diminuição da quantidade de infiltrado, sendo que a análise estatística dos valores obtidos com e sem o seu uso, mostraram significância a 1%. Além disso, com o uso do adesivo anaeróbico os três sistemas de implante testados passaram a ter comportamento semelhante, não tendo sido encontrada diferença estatística significante entre eles (p=0,5451). Considerando os limites deste estudo, pode-se concluir que os três sistemas de implante com conexão do tipo cone Morse testados permitiram a passagem de fluido do meio externo para o interior dos implantes, e que o material testado não foi capaz de impedir a penetração de fluido, apesar de ter reduzido significantemente a quantidade de infiltrado em todos os sistemas. / It has been observed that in implants with screw-retained abutments, in in vitro as well as in vivo conditions, bacteria and fluids can penetrate the inner implant space as consequence of an existing microgap at the implant-abutment interface. This fact can be related to peri-implant tissue inflammation and malodor. The aim of the present study was to evaluate and compare the occurrence of fluid penetration throught implant-abutment interface in three cone Morse implant systems and sealing ability of an anaerobic adhesive using a radioisotope as trace. In the first phase, ten implant-abutment sets of each system were immersed in a solution with radioisotope, after manufacture recommended torque application. All assemblies were kept in a constant pressure of 2 atm for one minute. In the second phase, an anaerobic adhesive was applied before the abutments been torque-tightened to the same implant. After the pressure application, material inside implant bodies was colleted using a paper cone that was transferred to tubes for posterior verification of radioactivity. Fluid penetration at the implant-abutment interface was seen to be a recordable phenomenon in each assembly of the three cone Morse systems tested in this study. The quantity of infiltrated varied between systems and assemblies. The variable of the samples was observed in all systems, however, it was noted that the value of infiltrate found in Group 1 was significantly higher than that found in Group 2, and there was no statistical significant difference between the groups 1 and 3, and between groups 2 and 3. It was also noted that, using the adhesive anaerobic, the implant systems showed reduce infiltrate, and statistical analysis presented significance to 1%. Moreover, with the use of anaerobic adhesive, all three implant systems tested presented similar pattern, and no significant statistical difference was found (p=0,5451). Considering the limits of this study, the following conclusions can be drawn: the three cone Morse implant systems tested allowed the passage of fluid from external to the inside of the implants, and that the material tested was not capable of preventing the fluid penetration, despite having reduced significantly the amount of infiltrate in all systems.