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Determinação do impacto da variação da viscosidade em resinas compostas auto-adesivas experimentais : análise da interface adesiva
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Abstract(s)
Objetivos: Avaliar e comparar a química interfacial, a taxa de conversão e zona de interdifusão formada, em dentina, de diferentes resinas compostas experimentais auto-adesivas, variando os monómeros funcionais e a viscosidade, através de microespectroscopia de Raman.
Materiais e métodos: Foram formuladas nove resinas compostas auto-adesivas, com uma matriz orgânica à base de dimetilacrilato de uretano (UDMA) e dimetacrilato de propileno glicol (PPGDMA), com a adição de 15 mol% de um monómero funcional (metacrilato de 2-hidroxietilo, HEMA; glicerolfosfato dimetacrilato, GPDM ou 10-metacriloiloxidecil dihidrogeno fosfato, 10-MDP). Para além da variação do monómero adesivo, foram testadas três proporções de pó-líquido (1.9, 2.2 e 2.5). Para o estudo espectroscópico, 27 dentes humanos molares hígidos foram seccionados, preparados (polidos com 600 SiC) e restaurados (incrementos de 2 mm ± 0,5 mm e fotopolimerizados a 20 s). Após armazenamento, foram seccionadas fatias de dente e posteriormente feito o mapeamento de Raman de uma área de superfície de 15 x 15 μm, entre 800 – 1750 cm-1 (resolução de 2 cm-1 a 50x). A análise de dados contemplou a criação de mapas por escalas de intensidade, o cálculo da taxa de conversão na interface (DC%) e o cálculo da largura da zona de interdifusão.
Resultados: A análise qualitativa das imagens espectroscópicas revelou que as formulações com 10-MDP contribuíram para a formação de uma zona de interdifusão, independente da proporção pó-líquido, e em contraste com os outros monómeros. Relativamente à DC%, as formulações de 10-MDP e HEMA mostraram-se superiores e similares, em comparação com o GPDM (HEMA vs. GPDM p<0,0001 e 10-MDP vs. GPDM p<0,001; Bonferroni). As resinas formuladas com o monómero 10-MDP apresentaram uma largura de zona de interdifusão significativamente superior às resinas formuladas com HEMA e GPDM. Para ambas as variáveis não foram identificadas diferenças na viscosidade (p>0,05).
Conclusão: Os monómeros funcionais presentes nas formulações de resina composta auto-adesiva influenciaram a qualidade e a largura da zona de interdifusão, bem como a taxa de conversão na interface adesiva. A variação da proporção de pó-líquido testada neste estudo não mostrou ter impacto sobre a interface adesiva.
Objectives: To evaluate and compare the interfacial chemistry, conversion rate and interdiffusion zone formed in dentin, of different experimental self-adhesive composite resins, varying the functional monomers and viscosity, using Raman micro-spectroscopy. Materials and methods: Nine self-adhesive composite resins were formulated, with an organic matrix based on urethane dimethylacrylate (UDMA) and propylene glycol dimethacrylate (PPGDMA), with the addition of 15 mol% of a functional monomer (either 2-hydroxyethyl methacrylate, HEMA; glycerolphosphate dimethacrylate, GPDM or 10-methacryloyloxydecyl dihydrogen phosphate, 10-MDP). In addition to varying the adhesive monomer, three powder-liquid ratios were tested (1.9, 2.2 and 2.5). For the spectroscopic study, 27 healthy human molar teeth were sectioned, prepared (polished with 600 SiC) and restored (increments of 2 mm ± 0.5 mm and light-cured at 20 s). After storage, tooth slices were sectioned and Raman mapping of a 15 x 15 μm surface area was carried out between 800 – 1750 cm-1 (resolution 2 cm-1 at 50x). Data analysis included the creation of intensity scale maps, calculation of the conversion rate at the interface (DC%) and calculation of the width of the interdiffusion zone. Results: Qualitative analysis of the spectroscopic images revealed that the formulations with 10-MDP contributed to the formation of an interdiffusion zone, irrespective of the powder-liquid ratio, and in contrast to the other monomers. In terms of DC%, the 10-MDP and HEMA formulations were superior and similar compared to GPDM (HEMA vs. GPDM p<0.0001 and 10-MDP vs. GPDM p<0.001; Bonferroni). The self-adhesive composites formulated with the 10-MDP monomer had a significantly wider interdiffusion zone than the resins formulated with HEMA and GPDM. For both variables, no differences in viscosity were identified (p>0.05). Conclusion: The functional monomers present in the self-adhesive composite formulations influenced the quality and width of the interdiffusion zone, as well as the conversion rate at the adhesive interface. The variation in the powder-liquid ratio tested in this study had no impact on the adhesive interface.
Objectives: To evaluate and compare the interfacial chemistry, conversion rate and interdiffusion zone formed in dentin, of different experimental self-adhesive composite resins, varying the functional monomers and viscosity, using Raman micro-spectroscopy. Materials and methods: Nine self-adhesive composite resins were formulated, with an organic matrix based on urethane dimethylacrylate (UDMA) and propylene glycol dimethacrylate (PPGDMA), with the addition of 15 mol% of a functional monomer (either 2-hydroxyethyl methacrylate, HEMA; glycerolphosphate dimethacrylate, GPDM or 10-methacryloyloxydecyl dihydrogen phosphate, 10-MDP). In addition to varying the adhesive monomer, three powder-liquid ratios were tested (1.9, 2.2 and 2.5). For the spectroscopic study, 27 healthy human molar teeth were sectioned, prepared (polished with 600 SiC) and restored (increments of 2 mm ± 0.5 mm and light-cured at 20 s). After storage, tooth slices were sectioned and Raman mapping of a 15 x 15 μm surface area was carried out between 800 – 1750 cm-1 (resolution 2 cm-1 at 50x). Data analysis included the creation of intensity scale maps, calculation of the conversion rate at the interface (DC%) and calculation of the width of the interdiffusion zone. Results: Qualitative analysis of the spectroscopic images revealed that the formulations with 10-MDP contributed to the formation of an interdiffusion zone, irrespective of the powder-liquid ratio, and in contrast to the other monomers. In terms of DC%, the 10-MDP and HEMA formulations were superior and similar compared to GPDM (HEMA vs. GPDM p<0.0001 and 10-MDP vs. GPDM p<0.001; Bonferroni). The self-adhesive composites formulated with the 10-MDP monomer had a significantly wider interdiffusion zone than the resins formulated with HEMA and GPDM. For both variables, no differences in viscosity were identified (p>0.05). Conclusion: The functional monomers present in the self-adhesive composite formulations influenced the quality and width of the interdiffusion zone, as well as the conversion rate at the adhesive interface. The variation in the powder-liquid ratio tested in this study had no impact on the adhesive interface.
Description
Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas Moniz
Keywords
Resinas compostas Monómero funcional Microespectroscopia de raman Auto-adesivas