Bioactive glass particulate filler composite: Effect of coupling of fillers and filler loading on some physical properties

WOS: 000334585200015PubMed ID: 24655591Objectives. The aim of this study was to investigate the effect of silanization of biostable and bioactive glass fillers in a polymer matrix on some of the physical properties of the composite. Methods. The water absorption, solubility, flexural strength, flexural modulus and toughness of different particulate filler composite resins were studied in vitro. Five different specimen groups were analyzed: A glass-free control, a non-silanized bioactive glass, a silanized bioactive glass, a non-silanized biostable glass and a silanized biostable glass groups. All of these five groups were further divided into sub-groups of dry and water-stored materials, both of them containing groups with 3 wt%, 6 wt%, 9 wt% or 12 wt% of glass particles (n = 8 per group). The silanization of the glass particles was carried out with 2% of gamma-3-methacryloxyproyltrimethoxysilane (MPS). For the water absorption and solubility tests, the test specimens were stored in water for 60 days, and the percentages of weight change were statistically analyzed. Flexural strength, flexural modulus and toughness values were tested with a three-point bending test and statistically analyzed. Results. Higher solubility values were observed in non-silanized glass in proportion to the percentage of glass particles. Silanization, on the other hand, decreased the solubility values of both types of glass particles and polymer. While 12 wt% non-silanized bioactive glass specimens showed -0.98 wt% solubility, 12 wt% silanized biostable glass specimens were observed to have only -0.34 wt% solubility. The three-point bending results of the dry specimens showed that flexural strength, toughness and flexural modulus decreased in proportion to the increase of glass fillers. The control group presented the highest results (106.6 MPa for flexural strength, 335.7 kPA for toughness, 3.23 GPa for flexural modulus), whereas for flexural strength and toughness, 12 wt% of non-silanized biostable glass filler groups presented the lowest (70.3 MPa for flexural strength, 111.5 kPa for toughness). For flexural modulus on the other hand, 12 wt% of silanized biostable glass filler group gave the lowest results (2.57 GPa). Significance. The silanization of glass fillers improved the properties of the glass as well as the properties of the composite. Silanization of bioactive glass may protect the glass from leaching at early stage of water storage. Crown Copyright (C) 2014 Published by Elsevier Ltd on behalf of The Academy of Dental Materials. All rights reserved.CIMO (Centre for International Mobility)This research was financially supported by CIMO (Centre for International Mobility) and it was carried out in Turku ClinicalBiomaterials Centre - TCBC, University of Turku, Finland. This research is part of the BioCity Turku Biomaterials Research Program (www.biomaterials.utu.fi). Minttu Vigren, Genevieve Alfont and Hanna Mark are thanked for their help with tests in TCBC. Professor Jukka Matinlinna (University of Hong Kong) is thanked for sharing his silane studies with us. Timothy Wilson is thanked for proofreading the manuscript