LUIZA MELLO DE PAIVA CAMPOS
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Artigo IPEN-doc 24192 Nfluence of radiation on the thermal and mechanical properties of BISGMA / TEGDMA based nanocomposites using pre-irradiated MMT nanoparticles as filler2017 - SANTOS, TAMIRIS M.R.; CAMPOS, LUIZA M.P.; SANTOS, MARIANA de J.; BOARO, LETICIA C.; PARRA, DUCLERC F.In the present study was observed the influence of gamma radiation in thermal and mechanical properties of the experimental dental composites based on BISGMA/TEGDMA filled with pre-irradiated MMT nanoparticles (Cloisite® 20A). MMT nanoparticle was pre-irradiated at doses of 10, 15 and 70 kGy. As a control group MMT nanoparticle was added in the polymeric matrix without pre-irradiation. Four formulations of experimental nanocomposites were studied all with 50% wt of filler. The characterization of the experimental composites was performed by means of the following techniques: Thermogravimetry Analysis (TGA), Elastic Modulus and Flexural Strength. It was observed that the group filled with pre-irradiated nanoparticles at dose of 70 kGy showed a delay in the decomposition temperature when compared to the control group. For elastic modulus the results showed a proportional increase related to the dose of radiation applied in the MMT nanoparticle. Regarding flexural strength, the groups filled with pre–irradiated nanoparticles and the control group presented similar results.Artigo IPEN-doc 22776 Avaliação da contração de polimerização de compósitos dentários experimentais a base de BISGMA/TEGDMA, adicionados com nanopartículas de montmorilonita2014 - CAMPOS, L.M.P.; SANTOS, L.K.G.; PARRA, D.F.; LUGAO, A.B.Esse trabalho investigou a contração de polimerização de compósitos experimentais (a base de BisGMA/TEGDMA) adicionados com nanopartículas de argila MMT Cloisite® 10A. Utilizou-se compósitos experimentais adicionados com sílica silanizada Aerosil® OX-50 como controle. Seis grupos de compósitos experimentais contendo 50, 60 e 70% de carga em massa foram investigados, sendo três grupos adicionados com MMT e três grupos adicionados com sílica silanizada. A caracterização dos compósitos experimentais foi realizada pelas seguintes análises: Análise Térmica-Mecânica (TMA); Calorimetria Exploratória Diferencial (DSC); Micro Dureza Knoop (MDK); Difração de Raio-X (DRX). A contração de polimerização variou de acordo com a concentração e o tipo de carga. Os compósitos experimentais adicionados com MMT apresentaram valores de contração entre 2,77 e 0,17% e os grupos adicionados com sílica silanizada apresentaram valores de contração entre 2,73 e 0,59%. Os valores de microdureza variaram entre 18 e 20 nos grupos de compósitos experimentais adicionados com MMT e entre 11 e 15 nos grupos controle adicionados com sílica silanizada. Por meio da Difração de Raio-X observou-se o fenómeno de intercalação da nanopartícula MMT na matriz polimérica e isso poderia justificar o melhor desempenho apresentado (menor contração de polimerização e maior valor de microdureza) em comparação aos grupos controle.Artigo IPEN-doc 22624 Chlorhexidine loaded MMT as dental composite filler: release evaluation2016 - CAMPOS, LUIZA M.; BOARO, LETICIA C.; SANTOS, TAMIRIS R.; SANTOS, VINICIUS J.; VARCA, GUSTAVO C.; PARRA, DUCLERC F.Polymeric restorative materials are widely used, however polymerization shrinkage still stands as a major drawback as it allows microleakage, secondary caries, postoperative sensitivity and cusp deflection. A polymeric material with antimicrobial activity could be very useful in many dental procedures including adhesive cementation, sealants, dental adhesives and direct restorative material. The aim of this study was to develop nanocomposites for dental purposes composed by chlorhexidine loaded montmorillonite (Cloisite 30B) nanoparticles in a BisGMA / TEGDMA organic matrix. The specimens of experimental composites were synthesized with 10 % (w/w) of diacetate chlorhexidine incorporated in a MMT, as filler. The chlorhexidine release at 37 oC was evaluated in vitro in physiological solution at neutral pH for 366 hours. Drug content was estimated by UV spectroscopy at λ=255 nm. Significant drug release initiated after 96 hours and maintained throughout the experiment. In conclusion, the composite was capable of promoting chlorhexidine release over time, and such results in addition to the lack of significant weight loss (≤ 1.43 %) and the very low swelling (≤ 2.22 %) properties, revealed the strong potential of the developed composite for further dental and other biomaterial applications.Artigo IPEN-doc 22345 Effect of MMT nanoparticle clay on flexural properties of polymer based Bis GMA / TEG DMA resin2016 - PARRA, DUCLERC; CAMPOS, LUIZA; BOARO, LETICIA; FERREIRA, HENRIQUE; LUGAO, ADEMAR; RANGARI, VIJAYAArtigo IPEN-doc 16833 Mechanical behavior of dental composite filling materials using digital holography2011 - CAMPOS, LUIZA M.P.; PARRA, DUCLERC F.; MONTEIRO, JAIME; VAZ, MARIO; VASCONCELOS, MARIO; CAMPOS, J.C.R.