Reactive fibre reinforced glass ionomer cements

The mechanical properties of glass ionomer cements used in restorative dentistry reinforced by chopped glass fibres were investigated. Reactive glass fibres with a composition in the system SiO2-Al2O3-CaF2-Na3AlF6 and a thickness of 26mum were drawn by a bushing process. The manufacturing parameters were optimized with respect to maximum strength of the glass fibre reinforced ionomer cements. Powder to liquid ratio, pre-treatment of the glass, grain size distribution and fibre volume fraction were varied. Glass fibre and cement were characterized by X-ray diffraction, transmission electron microscopy and energy dispersive spectroscopy techniques. respectively. The highest flexural strength of the reinforced cement (15.6 MPa) was found by compounding 20vol% reactive fibres and extending the initial dry gelation period Lip to 30 min. Microscopic examination of the fractured cements indicated a distinct reactive layer at the fibre surface. A pronounced fibre pull out mode gives rise to an additional work-of-fracture contributed by pulling the fibres out of the fracture surface. (C) 2003 Elsevier Science Ltd. All rights reserved.