Objectives: The aim of this study was to clarify characteristics of recent restorative glass-ionomer cements (GICs).
Methods: Five GICs, EHM-10 (EHM), FujiIX GP (FIX), GlasIonomer FX-II (GFX), Ketac Molar Easymix (KME), and Riva Self Cure (RSC), were examined. Compressive strength (CS) and surface hardness (Hv) of cylindrical specimens and cumulative fluoride release (CFR) from disk-shaped specimens were measured at 1 day, 1 week, 1 month, and 3 months after water storage(n = 5), and analyzed effects of type of GIC and storage period by 2-way ANOVA and Tukey HSD test (p < 0.05).
Results: Two-way ANOVA of CS revealed that two main factors (type of GIC and storage period) were significant (GFX < EHM = RSC < FIX < KME; 1 day < 1 week, 1 week = 1 month, 1 month > 3 months). Hv showed a similar tendency. Regarding CFR, 2-way ANOVA revealed that two main factors and their interaction were significant. At the first day, 15 to 25 % of 3-month cumulative fluoride ion was released. CFR at 3 months was as follows: FIX = KME < GFX < EHM < RSC. These results suggested that the mechanical properties increased due to the mature of acid-base reaction until 1 month, but decreased due to degradation such as fluoride ion release for 3-month water storage.
Conclusion: CS and Hv increased until 1 month; however, these properties showed a tendency to decrease at 3 months. The fluoride ion was continuously released until 3 months.