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Efeito da variação de monómeros funcionais na formulação de novas resinas auto-adesivas : estudo de microinfiltração e microscopia da interface
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Advisor(s)
Abstract(s)
Objetivos: Avaliar a microinfiltração marginal de resinas auto-adesivas experimentais, comparando com um compósito convencional experimental e um grupo controlo comercial com sistema adesivo.
Materiais e Métodos: 60 terceiros molares humanos hígidos extraídos foram divididos em 6 grupos experimentais (n=10), de acordo com a resina utilizada. Foram confecionadas 5 resinas auto-adesivas experimentais, utilizando como monómero base o dimetacrilato de uretano (UDMA) e o dimetacrilato de trietilenoglicol (TEGDMA). Além disso, 10% em peso de monómeros funcionais distintos foram adicionados - 10-MDP, HEAA, HEMA ou GPDM (UT_10MDP, UT_HEAA e UT_HEMA e UT_GPDM respetivamente), deixando UT_CTRL apenas com UDMA/TEGDMA, sendo o grupo de controlo. Foi adicionado 1% em peso de canforoquinona às misturas. Foi utilizada uma fase de carga híbrida de cargas de vidro silanizadas convencionais. Os compósitos foram misturados a uma razão pó-líquido de 1.2/1, usando um misturador de velocidade centrífuga (45 s, 1500 rpm). Foi adicionado um grupo de controlo comercial positivo com Optibond FLâ e 3MÔ FiltekÔ Z250 (OBFL_FILTEK). Foram preparadas cavidades padronizadas classe V e o procedimento restaurador foi realizado sem ataque ácido. Os incrementos foram adicionados e polimerizados durante 20s com uma irradiância medida de 950 mW/cm2. As amostras foram posteriormente divididas em dois grupos adicionais, com base no envelhecimento artificial (10.000 ciclos a 5º/55º) ou sem envelhecimento, seguido de imersão em fucsina básica a 0,5% por 24 h. Cada amostra foi seccionada no sentido ocluso-cervical e observada com lupa estereoscópica. Foram realizados o teste de Kruskal-Wallis e análise binomial (a=0,05).
Resultados: Não houve diferenças na distribuição dos resultados de microinfiltração entre as resinas auto-adesivas formuladas com monómeros funcionais em relação ao grupo controlo (Mann-Whitney U, p>0,05). O grupo OBFL_FILTEK teve um desempenho significativamente melhor do que todos os outros (p<0,05), sem microinfiltração. Todas as resinas experimentais tiveram mais de 40% de probabilidade de apresentar microinfiltração.
Conclusão: A adição de um monómero funcional à composição química de um compósito fluido parece não ser suficiente para melhorar sua capacidade de selamento.
Objectives: To evaluate the marginal microleakage of experimental self-adhesive composites, in comparison to experimental conventional composite and a commercial control group featuring an adhesive. Materials and Methods: 60 extracted sound human third molars were assigned to 6 experimental groups (n=10), according to the composite used. 5 experimental selfadhesive composites were made, using urethane dimethacrylate (UDMA) as a base monomer, and triethylene glycol dimethacrylate (TEGDMA). Additionally, 10 wt. % of distinct functional monomers were added 10-MDP, HEAA, HEMA or GPDM (UT_10MDP, UT_HEAA and UT_HEMA and UT_GPDM respectively), leaving UT_CTRL with UDMA/TEGDMA only, as the control group. 1 wt.% camphorquinone was added to the mixtures. A hybrid filler phase of conventional silanized glass fillers was used. Composites were mixed at a powder-liquid-ratio of 1.2/1, using a centrifugal speed mixer (45 s, 1500 rpm). A positive commercial control group of Optibond FLâ and 3MÔ FiltekÔ Z250 (OBFL_FILTEK) was added. Class V standardized cavities were prepared and for the restorative procedure, no etching was carried out. Increments were added and cured for 20s at a measured peak irradiance of 950 mW/cm2. Samples were further divided into two additional groups, based on artificial aging (10 000 cycles at 5º/55º) or no aging, followed by immersion in 0.5% basic fuchsin for 24 h. Each sample was sectioned in the occlusal-cervical direction and observed with a stereoscopic magnifier. Kruskal-Wallis test and binomial analyses (a=0.05) were undertaken. Results: There were no differences in microleakage score distribution among the formulated self-adhesive composites with functional monomers compared to the control group (Mann-Whitney U, p>0.05). However, the OBFL_FILTEK group performed significantly better than all others (p<0.05), with no microleakage. All experimental composites had more than 40% chance of having microleakage. Conclusion: Adding a functional monomer to the chemical composition of a flowable composite does not seem to be enough to improve its sealing ability.
Objectives: To evaluate the marginal microleakage of experimental self-adhesive composites, in comparison to experimental conventional composite and a commercial control group featuring an adhesive. Materials and Methods: 60 extracted sound human third molars were assigned to 6 experimental groups (n=10), according to the composite used. 5 experimental selfadhesive composites were made, using urethane dimethacrylate (UDMA) as a base monomer, and triethylene glycol dimethacrylate (TEGDMA). Additionally, 10 wt. % of distinct functional monomers were added 10-MDP, HEAA, HEMA or GPDM (UT_10MDP, UT_HEAA and UT_HEMA and UT_GPDM respectively), leaving UT_CTRL with UDMA/TEGDMA only, as the control group. 1 wt.% camphorquinone was added to the mixtures. A hybrid filler phase of conventional silanized glass fillers was used. Composites were mixed at a powder-liquid-ratio of 1.2/1, using a centrifugal speed mixer (45 s, 1500 rpm). A positive commercial control group of Optibond FLâ and 3MÔ FiltekÔ Z250 (OBFL_FILTEK) was added. Class V standardized cavities were prepared and for the restorative procedure, no etching was carried out. Increments were added and cured for 20s at a measured peak irradiance of 950 mW/cm2. Samples were further divided into two additional groups, based on artificial aging (10 000 cycles at 5º/55º) or no aging, followed by immersion in 0.5% basic fuchsin for 24 h. Each sample was sectioned in the occlusal-cervical direction and observed with a stereoscopic magnifier. Kruskal-Wallis test and binomial analyses (a=0.05) were undertaken. Results: There were no differences in microleakage score distribution among the formulated self-adhesive composites with functional monomers compared to the control group (Mann-Whitney U, p>0.05). However, the OBFL_FILTEK group performed significantly better than all others (p<0.05), with no microleakage. All experimental composites had more than 40% chance of having microleakage. Conclusion: Adding a functional monomer to the chemical composition of a flowable composite does not seem to be enough to improve its sealing ability.
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
Adesão dentária Microinfiltração Monómeros funcionais Resinas autoadesivas