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Efeito da variação de monómeros funcionais na formulação de novas resinas auto-adesivas : estudo de citotoxicidade
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Abstract(s)
Introdução: Avaliar e comparar a citotoxicidade de resinas compostas autoadesivas experimentais, formuladas com diferentes monómeros funcionais, pelo método indireto de extrato, às 24 horas, utilizando células do tipo préodontoblásticas (MDPC23).
Métodos: Para o presente estudo foram formuladas 5 resinas autoadesivas, com variação do monómero funcional adesivo/surfactante. A mistura de resina líquida consistiu em dimetacrilato de uretano (UDMA) a 60 wt%, com adição de 24 wt% de dimetacrilato de trietilenoglicol (TEGDMA) como diluente. Em 4 dos 5 grupos experimentais foram adicionados 10 wt% de diferentes monómeros funcionais: 10MDP, GPDM, HEAA e
HEMA. A última formulação, de controlo, teve 10 wt% adicionais de UDMA, sem monómero funcional. Foi adicionado ainda 1% de canforoquinona à fase líquida. A fase particulada incluiu vidros de bário e aluminossilicatos (1,5 μm e 0,4 μm) e nanopartículas de sílica. Os compósitos foram misturados numa proporção pólíquido de 1.2:1, com recurso a uma misturadora centrífuga. Cada resina foi introduzida em anéis de silicone do tipo ORing de dimensões padronizadas, procedendo-se de seguida à polimerização de 8 discos de resina por grupo experimental. Os discos foram esterilizados com recurso a radiação UV, tendo sido subsequentemente introduzidos no condicionamento de meio celular numa proporção de 1:1 (incubação 24 horas sob agitação). Foi utilizada uma cultura celular do tipo préodontoblastos (MDPC23) num ensaio de citotoxicidade de 3 (4,5Dimetiltiazol2yl) 2,5Difenil Tetrazolium (MTT) realizado 24h após a exposição das células aos extratos em diferentes concentrações, tendo sido posteriormente calculada a viabilidade celular.
Resultados: Foram registadas diferenças entre os grupos estudados em concentrações abaixo de 100% (50, 25, 12,5 e 6,25%) e entre os grupos experimentais contendo HEMA e HEAA como monómeros funcionais.
Conclusões: Todas as resinas autoadesivas testadas demonstraram desencadear respostas de citoxicidade, em concentrações elevadas, 24 horas após a administração dos extratos, sendo que este nível de toxicidade varia em função da formulação.
Introduction: To evaluate and compare the cytotoxicity of experimental selfadhesive compounds, formulated with different functional monomer resins, by the indirect extractor method, at 24h, using preodontoblast cells (MDPC23). Methods: For the present study, 5 different selfadhesive resins were formulated, with a set of adhesive/surfactant monomer. The liquid blend resin included 60 wt% urethane dimethacrylate (UDMA), combined with 24 wt% of triethylene glycol dimethacrylate (TEGDMA) as a diluent. In 4 of the 5 experimental groups, 10 wt% was composed by a different functional monomer: 10MDP, GPDM, HEAA and HEMA. The last formulation, the control group, had an additional 10 wt% of UDMA, not containing a functional monomer. A further 1wt% of camphorquinone was added to the liquid phase. The particulate phase included barium and aluminosilicate glasses (1.5 μm and 0.4 μm) and silica nanoparticles. The composites were blended in a 1.2:1 powdertoliquid ratio using a centrifugal mixer (45 s, 1500 rpm). Each resin was then introduced in silicone rings, being then polymerized and producing 8 discs per group. The discs were sterilized using UV radiation and were subsequently introduced into the cell medium conditioning at a ratio of 1:1 (24 hours incubation under agitation). A preodontoblasttype cell culture (MDPC23) was used in an 3 (4,5dimethylthiazol2yl) 2,5diphenyltetrazolium bromide (MTT) cytotoxicity assay performed 24h after cell exposure to the extracts at different concentrations. Cell viability was subsequently calculated. Results: Differences were only registered for concentrations below 100% (50, 25, 12.5 and 6.25%) and between the experimental groups containing HEMA and HEAA. Conclusions: All the selfadhesive resins tested showed to be cytotoxic, in high concentrations, 24 hours after cell exposure to the extracts, varying with the different formulations.
Introduction: To evaluate and compare the cytotoxicity of experimental selfadhesive compounds, formulated with different functional monomer resins, by the indirect extractor method, at 24h, using preodontoblast cells (MDPC23). Methods: For the present study, 5 different selfadhesive resins were formulated, with a set of adhesive/surfactant monomer. The liquid blend resin included 60 wt% urethane dimethacrylate (UDMA), combined with 24 wt% of triethylene glycol dimethacrylate (TEGDMA) as a diluent. In 4 of the 5 experimental groups, 10 wt% was composed by a different functional monomer: 10MDP, GPDM, HEAA and HEMA. The last formulation, the control group, had an additional 10 wt% of UDMA, not containing a functional monomer. A further 1wt% of camphorquinone was added to the liquid phase. The particulate phase included barium and aluminosilicate glasses (1.5 μm and 0.4 μm) and silica nanoparticles. The composites were blended in a 1.2:1 powdertoliquid ratio using a centrifugal mixer (45 s, 1500 rpm). Each resin was then introduced in silicone rings, being then polymerized and producing 8 discs per group. The discs were sterilized using UV radiation and were subsequently introduced into the cell medium conditioning at a ratio of 1:1 (24 hours incubation under agitation). A preodontoblasttype cell culture (MDPC23) was used in an 3 (4,5dimethylthiazol2yl) 2,5diphenyltetrazolium bromide (MTT) cytotoxicity assay performed 24h after cell exposure to the extracts at different concentrations. Cell viability was subsequently calculated. Results: Differences were only registered for concentrations below 100% (50, 25, 12.5 and 6.25%) and between the experimental groups containing HEMA and HEAA. Conclusions: All the selfadhesive resins tested showed to be cytotoxic, in high concentrations, 24 hours after cell exposure to the extracts, varying with the different formulations.
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
Monómero funcional Auto-adesiva Resina composta Citotoxicidade