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Determinação do impacto da variação da viscosidade em resinas compostas auto-adesivas experimentais : adesão e propriedades reológicas
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Abstract(s)
Objetivos: Avaliar e comparar a resistência adesiva à dentina e a viscosidade, de diferentes resinas compostas auto-adesivas (RCA) flowable experimentais formuladas com diferentes monómeros funcionais e proporções de pó para líquido.
Materiais e métodos: Foram produzidos 9 RCA, à base de dimetilacrilato de uretano (UDMA) e dimetacrilato de propileno glicol (PPGDMA), variando o monómero funcional (i.e., metacrilato de hidroxietilo, HEMA; glicerolfosfato dimetacrilato, GPDM; 10-metacriloiloxidecil dihidrogeno fosfato, 10-MDP) e a fase inorgânica híbrida, com vidros de bário e nanopartículas de sílica. Diferentes formulações foram alcançadas variando a proporção de pó e líquido, obtendo-se os rácios de 2.5, 2.2 e 1.9. A viscosidade das soluções não polimerizadas foi estudada através de um ensaio de escoamento (n=3), à temperatura ambiente com variação da taxa de cisalhamento de 0 a 100 s-1. As RCA foram analisadas em termos de capacidade de adesão à dentina. Inicialmente, 54 dentes humanos hígidos foram cortados e lixados de forma a expor a dentina. Foi realizada uma cavidade de cerca de 2 mm de altura, onde cada RCA foi colocada e polimerizada. De seguida, os dentes foram armazenados durante 24 h a 37 ºC. A resistência ao deslocamento adesivo foi estudada por perfilometria após um ensaio de desgaste por teste de raspagem (0.25 N, 1 N e 5 N, 10N, 15N e 30N, 4 mm amplitude, a 0.0875 mm/min) (n=3). Métodos de estatística descritiva e inferencial de modo a testar as hipóteses nulas formuladas, com recurso ao software SPSS v. 26.0 com nível de significância de 5% foram realizados.
Resultados: O ensaio de viscosidade mostrou que todas as RCA experimentais, em todos os rácios testados, apresentaram comportamento não-newtoniano, ou seja, a medida que a força de cisalhamento aumentava, diminuía a viscosidade. Enquanto ao teste de arranhão, as resinas formuladas com os monómeros GPDM e HEMA, nos rácios de 2.5, descolaram-seda dentina com as forças de 30 N.
Conclusão: O ensaio de viscosidade mostrou as resinas compostas auto-adesivas experimentais variavam em viscosidade devido não só ao rácio, mas também ao monómero funcional. A variação do monómero funcional nas resinas experimentais auto-adesivas, afeta significativamente a resistência a força de adesão destes materiais.
Objectives: To evaluate and compare the dentin bond strength and viscosity of different experimental flowable self-adhesive composite resins (SCR) formulated with different functional monomers and powder to liquid ratios. Materials and methods: Nine RCA were produced, based on urethane dimethylacrylate (UDMA) and dimetacrilato de propileno glicol (PPGDMA), varying the functional monomer (i.e., hydroxyethyl methacrylate, HEMA; glycerol dimethacrylate, GPDM; 10-methacryloyloxydecyl dihydrogen phosphate, 10-MDP) and the hybrid inorganic phase, with barium glasses and silica nanoparticles. Different formulations were achieved by varying the proportion of powder and liquid, obtaining the ratios of 2.5, 2.2 and 1.9. Canforoquinone (CQ) was added to all RCA, as a photoinitiator. The viscosity of the unpolymerized solutions was studied through a flow test (n=3), at room temperature with variation of the shear rate from 0 to 100 s-1. The RCA were analyzed in terms of their ability to adhere to the dentin. Initially, 54 healthy human teeth were cut and sanded in order to expose the dentin. A cavity of about 2 mm in height was made in each dentin, where each RCA was placed and polymerized. The teeth were then stored with the RCA for 24 h at 37 °C. The surface roughness of the polymerized samples was studied by profilometry before and after a scratch test (0.25 N, 1 N , 5 N, 15 N e 30 N, 4 mm scratch width, at 0.0875 mm/min) (n=3). Descriptive and inferential statistical methods in order to test the null hypotheses formulated, using SPSS v. 26.0 software at 5% significance level were performed. Results: The admission test showed that all experimental self-adhesive composite resins, in all tested ratios, presented non-Newtonian behavior, that is, as the shear force increased, admission decreased. As for the scratch test, the resins formulated with GPDM and HEMA monomers in ratios of 2.5, detached from silk dentin with forces of 30 N. Conclusion: The viscosity test showed that the experimental self-adhesive composite resins varied in viscosity due not only to the ratio, but also to the functional monomer. The functional monomer variation in self-adhesive experimental resins significantly affects the resistance and bond strength of these materials.
Objectives: To evaluate and compare the dentin bond strength and viscosity of different experimental flowable self-adhesive composite resins (SCR) formulated with different functional monomers and powder to liquid ratios. Materials and methods: Nine RCA were produced, based on urethane dimethylacrylate (UDMA) and dimetacrilato de propileno glicol (PPGDMA), varying the functional monomer (i.e., hydroxyethyl methacrylate, HEMA; glycerol dimethacrylate, GPDM; 10-methacryloyloxydecyl dihydrogen phosphate, 10-MDP) and the hybrid inorganic phase, with barium glasses and silica nanoparticles. Different formulations were achieved by varying the proportion of powder and liquid, obtaining the ratios of 2.5, 2.2 and 1.9. Canforoquinone (CQ) was added to all RCA, as a photoinitiator. The viscosity of the unpolymerized solutions was studied through a flow test (n=3), at room temperature with variation of the shear rate from 0 to 100 s-1. The RCA were analyzed in terms of their ability to adhere to the dentin. Initially, 54 healthy human teeth were cut and sanded in order to expose the dentin. A cavity of about 2 mm in height was made in each dentin, where each RCA was placed and polymerized. The teeth were then stored with the RCA for 24 h at 37 °C. The surface roughness of the polymerized samples was studied by profilometry before and after a scratch test (0.25 N, 1 N , 5 N, 15 N e 30 N, 4 mm scratch width, at 0.0875 mm/min) (n=3). Descriptive and inferential statistical methods in order to test the null hypotheses formulated, using SPSS v. 26.0 software at 5% significance level were performed. Results: The admission test showed that all experimental self-adhesive composite resins, in all tested ratios, presented non-Newtonian behavior, that is, as the shear force increased, admission decreased. As for the scratch test, the resins formulated with GPDM and HEMA monomers in ratios of 2.5, detached from silk dentin with forces of 30 N. Conclusion: The viscosity test showed that the experimental self-adhesive composite resins varied in viscosity due not only to the ratio, but also to the functional monomer. The functional monomer variation in self-adhesive experimental resins significantly affects the resistance and bond strength of these materials.
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
Monómero funcional Auto-adesiva Resina composta Força de descolamento adesivo