The effect of ceramic and porous filters on the mechanical properties of experimental dental composites

Objectives. The purpose of this study was to investigate the effect of ceramic fitters (containing leucite crystals) and their porosity on the mechanical properties of a new experimental dental composite in order to compare with the properties of composites containing conventional glass fitters. Methods. In this study, experimental composites were prepared by mixing the silane-treated fitters with monomers. Experimental composites were divided into four groups according to their fitter type, amount and porosity. The monomers were composed of 70% Bis-GMA and 30% TEGDMA by weight for all groups. Glass and leucite-containing ceramic were prepared as different fitter types. In order to make fitters porous, leucite-containing-ceramic fitters were treated with HF acid. Camphorquinone and DMAEMA were used as photo initiator system. Post-curing was done for all groups before mechanical testing. Degree of Conversion of composites was measured using FTIR spectroscopy. The diametral tensile strength (DTS), flexural strength and flexural modulus were measured and compared among the groups. Results. The results showed that the stronger and more porous fitter has a positive effect on flexural strength. Porosity of fitter increased flexural strength significantly. No significant difference was found in DTS tests among the groups. Flexural modulus was affected and increased by using ceramic fitters. The type of the filter affected the DC of the composite and DC increased by post-curing. Significance: Flexural strength is one of the most important properties of restorative dental materials. Higher flexural strength can be achieved by stronger and more porous fitters. Investigation into the effect of fitter on dental material properties would be beneficial in the development of restorative dental material. (c) 2005 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.