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BioMed Research International
Volume 2018, Article ID 9845427, 6 pages
https://doi.org/10.1155/2018/9845427
Research Article

Chemical and Mechanical Properties of Experimental Dental Composites as a Function of Formulation and Postcuring Thermal Treatment

1School of Dentistry, University Federal of Pará, Rua Augusto Corrêa 01, 66075-110 Belém, PA, Brazil
2School of Dentistry, University of Santo Amaro, Rua Professor Enéas de Siqueira Neto 340, 04829-300 São Paulo, SP, Brazil
3University Ibirapuera, Av. Interlagos 1329, 04661-100 São Paulo, SP, Brazil
4Nuclear and Energy Research Institute, University of São Paulo, Av. Lineu Prestes 2242, 05508-000 São Paulo, SP, Brazil
5Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, Av. Lineu Prestes 2227, 05508-900 São Paulo, SP, Brazil

Correspondence should be addressed to Flávia Gonçalves; rb.ude.areuparibi@sevlacnog.aivalf

Received 13 November 2017; Accepted 13 February 2018; Published 15 March 2018

Academic Editor: Jianshu Li

Copyright © 2018 Renata A. Esteves et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study evaluated the influence of formulation and thermal treatment on the degree of conversion, fracture toughness, flexural strength, and elastic modulus of experimental composites. Six composites were analyzed at BisGMA : TEGDMA molar ratios of 1 : 1 and 7 : 3 with filler at 30, 50, and 70 wt%. The degree of conversion was analyzed by Fourier transform infrared spectroscopy, fracture toughness was measured using the single-edge notched beam, and flexural strength and elastic modulus were measured with the 3-point bend test. For all tests, one-half of the specimens received thermal treatment at 170°C for 10 min. Data were analyzed by the Kruskal-Wallis or ANOVA/Tukey’s test (α = 5%). The 1 : 1 BisGMA : TEGDMA ratio showed higher properties than the 7 : 3 ratio. Although the material with 70% filler had a conversion lower than the one with 50%, it showed higher mechanical properties. The thermal treatment improved all properties in all materials. Therefore, the use of an equimolar ratio of BisGMA : TEGDMA can be paired with 70 wt% filler to design dental composites that possess increased advantageous physical and chemical properties. Furthermore, the simple and low-cost method of thermal treatment proposed for use in clinical dentistry has been shown to effectively improve the properties of all evaluated materials.