Effect of silanization of hydroxyapatite fillers on physical and mechanical properties of a bis-GMA based resin composite

To evaluate the physical and mechanical properties of an experimental bis-GMA-based resin composite incorporated with non-silanized and silanized nano-hydroxyapatite (nHAP) fillers. Experimental bis-GMA based resin composites samples which were reinforced with nHAP fillers were prepared. Filler particles were surface treated with a silane coupling agent. Five test groups were prepared: 1. Unfilled, 2. Reinforced with 10 wt% and 30 wt% non-silanized nHAP fillers, and 3. Reinforced with 10 wt% and 30 wt% silanized nHAP fillers. The samples were subjected to tests in dry condition and in deionized water, aged at 37 degrees C for 30 days. Prepared silanized and non-silanized nHAP were analyzed with Fourier Transform Infrared (FTIR) Spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The micro hardness and water sorption were evaluated. Data were analyzed by one-way ANOVA (p <0.05). The samples were characterized by FTIR Spectroscopy, Thermogravimetric Analysis and Differential Scanning Calorimetry. The surface morphology of sample surfaces was examined by Scanning Electron Microscope (SEM). The results showed that the water sorption for nHAP fillers reinforced resins was significantly lower than unfilled resins. Surface hardness for resins reinforced with silane treated fillers was superior to unfilled and untreated fillers resins. The resin matrix loaded with 30 wt% silanized-nHAP fillers would improve the physical and mechanical properties of a bis-GMA based resin. (C) 2015 Elsevier Ltd. All rights reserved.