The purpose of this study was to evaluate the strength and hardness of glass ionomer cements reinforced with amalgam alloys of various types and volume ratios as a core material.
Seven kinds of amalgam alloys were used in this study. Five of amalgam alloys were lathe cut type, one of them was spherical type and another one of them was admixed type.
For this study, glass ionomer cements for filling (Type II) and Miracle Mix were used as
control groups. The volume ratios of amalgam alloys added to glass ionomer cements were 10%, 15%, 20%, 25% and 30%.
The compressive and diametral tensile strength was measured after 24 hours from the start of mixing usingTnstron Universal Testing Instrument, and the Vickers hardness was measured=-using Vickers microhardness tester.
From the experiment, the following results were obtained:
l The compressive strength, in case of adding lathe-cut and admixed amalgam alloys was significantly high at 15% and 25% volume ratios among the volume ratio groups respectisely, and in case of adding spherical amalgam alloy, it was high at 15% and 20% volume ratios; but not significant.
2 The diametral tensile strength, in case of adding spherical amalgam alloy was significantly high at 20% volume ratio among the volume ratio groups, and in case of adding admixed and lathe-cut amalgam alloys, it was high at 15% volume ratio and low at 15% and 20% volume ratios respectively, but not significant,
3 In case of adding spherical amalgam alloy, the diametral tensile strength was high at the volume ratio which the compressive strength was high, and in case of adding lathe-cut amalgam alloy, it was low at the volume ratio which the compressive strength was high, but in case of adding admixed amalgam alloy, there was no correlation between the compressive and diametral tensile strength in accordance with volume ratio
4There was no significant difference in the Vickers hardness in accordance with the type of amalgam alloy and volume ratio.
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