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Water Transport in Resin-modified Glass-ionomer Dental Cement

Department of Chemistry, IUT Bethune, University of Artois 1230 rue de l'Université, 62408 Bethune, France

Denis Dubois

Department of Chemistry, IUT Bethune, University of Artois 1230 rue de l'Université, 62408 Bethune, France

J.W. Nicholson

Biomaterials Chemistry Group, School of Science, University of Greenwich Medway Campus, Chatham, Kent, United Kingdom, J.W.Nicholson{at}gre.ac.uk

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 (12°C), 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 12°C. Diffusion coefficients were between 0.45 and 0.76 x 10 ^-7 cm²/s, with low temperature diffusion coefficients slightly greater than those at room temperature. Plotting water loss as percentage versus s^- 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.

Key Words: resin-modified glass-ionomer • water sorption • water loss • kinetics.

This version was published on November 1, 2008

Journal of Biomaterials Applications, Vol. 23, No. 3, 263-273 (2008)
DOI: 10.1177/0885328208088863


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