Early and long-term wear of ‘Fast-set’ conventional glass–ionomer cements

Fast setting high viscous glass–ionomer cements have been introduced to reach the set state sooner and to improve early mechanical properties. The aim of this study was to investigate whether ‘fast-set’ cements have improved the early three-body wear. The three-body wear of four glass–ionomer cements was measured after 1, 4, 7, 30, 90, and 365 days. The chemical composition of the cements was determined with EDAX. The particle size of the powders was determined with a Mastersizer 2000. The three-body wear of Fuji IX Fast was only slightly less than that of ‘regular-set’ Fuji IX, but Ketac Molar Quick showed a higher wear compared to the regular-set Ketac Molar. The wear rate of all four glass–ionomer cements decreased over a period of 1 year and could be described by second order reaction kinetics and depended on polyalkenoic acid content, chemical composition, and the size of the glass particles. Based on the results of this laboratory study on long-term wear, the glass–ionomer cements investigated may compete with composites, but the early wear characteristics should be further improved. Furthermore, a better understanding of the wear and reaction behavior of glass–ionomer cements is obtained.