Development of a Novel Resin-Modified Glass-Ionomer Cement With Improved Mechanical Properties

Objectives: Development of a novel RMGICs containing a ceramic (zirconia) reinforced glass ionomer cement powder and a liquid containing alternative monomers to hydroxyethyl methacrylate (HEMA), with improved mechanical properties and reduced water uptake compared to commercial materials.
Methods: Powder of two commercial materials were used in this study. Powder 1: Amalgomer CR (AHL, UK) which contains a ceramic filler (zirconia) and powder 2: Fuji II LC (GC, Japan). These powders were mixed with two liquids, one containing HEMA and the other containing 50%/50% tetrahydrofurfuryl methacrylate (THFM) and HEMA, respectively. The powder and liquid were mixed and poured into PTFE moulds and light cured for 20 sec to produce samples. Fuji II LC (GC, Japan) was used as a control. Samples (n=6) were tested with respect to flexural strength (25mm, 2mm, 2mm), water uptake and desorption (15mm diameter, 1mm thickness). All materials were characterised using Fourier Transform Infrared Spectroscopy (FT-IR).
Results: As confirmed by FT-IR, all materials showed evidence of polymerisation following irradiation for 20 seconds. All novel RMGICs showed improved flexural strength values compared to commercial Fuji II LC. Moreover, novel RMGICs containing ceramic reinforced powder (Amalgomer CR) showed significantly higher flexural strength compared to all other materials tested. Materials incorporating 50%THFM showed significantly lower water uptake compared to their counterparts incorporating 100% HEMA.
Conclusions: Partially replacing HEMA with THFM reduced the water uptake of light-cured RMGICs. Furthermore, groups containing Amalgomer CR ceramic reinforced glass powder showed promising results with improved mechanical properties, which warrant further investigations.