Water Transport in Resin-modified Glass-ionomer Dental Cement

Abstract

Water uptake and water loss have been studied in a commercial resin-modified glass-ionomer cement, Fuji II LC, under a variety of conditions. Uptake was generally non-Fickian, but affected by temperature. At room temperature, the equilibrium water uptake values varied from 2.47 to 2.78% whereas at low temperature (128C), it varied from 0.85 to 1.18%. Cure time affected uptake values significantly. Water uptake was much lower than in conventional glass-ionomer restorative cements exposed to water vapor. Loss of water under desiccating conditions was found to be Fickian for the first 5 h loss at both 22 and 128C. Diffusion coefficients were between 0.45 and 0.76  10 À7 cm 2 /s, with low temperature diffusion coefficients slightly greater than those at room temperature. Plotting water loss as percentage versus s À½ allowed activation energies to be determined from the Arrhenius equation and these were found to be 65.6, 79.8, and 7.7 kJ/mol respectively for 30, 20, and 10 s cure times. The overall conclusion is that the main advantage of incorporating HEMA into resin-modified-glass-ionomers is to alter water loss behavior. Rate of water loss and total amount lost are both reduced. Hence, resin-modified glass-ionomers are less sensitive to water loss than conventional glass-ionomers.

Influence of Chemical Degradation on the Surface Properties of Nano Restorative Materials

“…Still, the highly hydrophilic hydroxyethyl methacrylate (HEMA) present in resin-modified glass ionomer (RMGI) makes this material also susceptible to the disintegration of its matrix, in a variable performance heavily dependent on the resin matrix composition and polymerization reactions. 6 The application of nanotechnology to composite resins was introduced by Filtek Supreme (3M-ESPE, St. Paul, MN, USA), which contains a unique combination of nanofillers (5-75 nm) and nanoclusters embedded in an organic polymer matrix. In addition to improved optical properties, nano materials present better mechanical behavior, 7 since the particle size increased the nanofiller load in the restorative materials.…”

The effects of acid erosion and remineralization on enamel and three different dental materials: FT‐Raman spectroscopy and scanning electron microscopy analysis

“…C and A) were probably due to the protective effect of gloss layer which must be applied at the end of restoration process and to the fluoride ion release. RMGICs have many of the desirable properties of conventional GICs as fluoride release (Croll and Nicholson, ), ability to buffer cariogenic acids in situ (Nicholson and Czarnecka, ), and the ability to release clinically beneficial ions, such as calcium and phosphate (Nicholson and Czarnecka, ; Percq et al, ). Under acidic conditions GIC based materials are prone to release ions depending on their chemical composition and acidity of the media (Hazar‐Yoruc et al, ).…”

Comparative Evaluation of Water Sorption, Solubility, and Microhardness of Zirconia-reinforced Glass Ionomer, Resin-modified Glass Ionomer, and Type IX Glass Ionomer Restorative Materials: An In Vitro Study

“…The powders also have different grain sizes and different additives, such as yttrium oxide and alumina, which are distributed homogeneously throughout the whole material. 13 This is important as the grain-size variety affects the resulting porosity as well as the translucency of the cement. The polyalkenoic acid and the glass components have been specially processed to impart superior mechanical and handling qualities.…”