Mechanical properties of two restorative reinforced glass-ionomer cements

This study investigated the mechanical properties (hardness, compressive and diametral tensile strength) of two restorative reinforced glass-ionomer cements (GC Fuji IX GP and Miracle Mix). The mechanical properties of the two cements were compared after 1 day, 1 week and 1 month storage in distilled water at 37 degrees C. Hardness testing (VHN) was carried out with a digital microhardness tester (load = 50 g, dwell time = 30 s) and compressive/diametral tensile strength testing (MPa) was conducted based upon British Standard Specification for Glass-Ionomer Cements (BS 6039: 1981). Results were analysed using analysis of variance (ANOVA)/Scheffe's test and independent samples t-test (P < 0.05). Mechanical properties generally increased with time for both cements. Hardness at 1 day was significantly lower than that at 1 week and 1 month. No significance difference in compressive and diametral tensile strengths was observed between the different time intervals. After 1 month storage in water, no significant difference in hardness and compressive strength was observed between Fuji IX and Miracle. The diametral tensile strength of Fuji IX was, however, significantly greater than that of Miracle Mix at all time intervals. Fuji IX GP may serve as a potential substitute for Miracle Mix.