Síntese e análise de compósitos experimentais para uso odontológico reforçados com nanoargila

• Autor(a) principal: Ritto, Fernanda Pitta
• Data de Publicação: 2014
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/14066
• topic: Dental composite; Nanoclay; Biocompatibility; Polymerization shrinkage; Mechanical properties; Compósito odontológico; Nanoargila; Biocompatibilidade; Contração de polimerização; Propriedades mecânicas; CNPQ::CIENCIAS DA SAUDE::ODONTOLOGIA

The aim of the present study was to evaluate the effect of different weight fractions of modified montmorillonite nanoclay fillers Cloisite ® 20A on mechanical, physical and biological properties of nanohybrid experimental resins. Dental composites were prepared by mixing 30% of resin matrix (BisGMA / TEGDMA) to 70% of particulate fillers (Silanized barium silicate particles - BS, silicone dioxide - SD, montmorillonite nanoclay cloisite 20AMMT). Four groups of experimental composite were formed with various fractions of the nanoclay fillers (0%; 5%; 7,5%; 10% ). Processing was performed using a dual high speed mixing machine (SpeedMixer DAC, Germany, 3500 rpm). In vitro citotoxicity of the material was calculated based on standards ISO 10993-5-2009 and compared to a comercial composite. Tensile strenght and elastic modulus were performed using an universal test machine EMIC. The volumetric shrinkage was calculated by Acuvol® machine. Water sorption and solubility were measured based on International Standard ISO 4049. Data were statistically analyzed by ANOVA and Tukey Test for multiple comparisons. The significance level utilized was 95% (p < 0,05). By the results, it was concluded that it is possible to exfoliate nicely 5 and 7.5% of MMT particles inside Bis-GMA/TEGDMA matrix. However, insertion of 10% of MMT did not improve composite, certainly, because the total exfoliation of particles did not occured. Insertion of 5 and 7.5% of nanoclay in dental composite diminished polymerization shrinkage in 22,13% and 17,4% , respectively. Furthermore, these two groups maintained their mechanical properties, satisfactory sorption and solubility and also presented no citotoxicity for L929 fibroblastic cells