A comparative investigation on the compressive strength has been done between the RTL dental amalgam alloy manufactured by the Army Research and Testing Laboratory of the Republic of Korea and 2 different kinds of conventional amalgams with different ...
A comparative investigation on the compressive strength has been done between the RTL dental amalgam alloy manufactured by the Army Research and Testing Laboratory of the Republic of Korea and 2 different kinds of conventional amalgams with different alloy mercury ratio and condensation pressure.
Four different alloy mercury ratios of 1.0:1.0, 1.0:1.2, 1.0:1.4, (non mercury squeeze) and 1.0:1.4 (mercury squeeze) were selected and six different condensation pressures were adopted: 3.5kg/㎠, 10.5kg/㎠, 21.1kg/㎠, 28.2kg/㎠, 60.0kg/㎠, and 98.8kg/㎠.
A total of 240 different amalgam test specimens prepared under these condensation pressures were tested for their compressive strengths after 24 hours. The Amsler Universal Testing Machine was used st a rate of loading of 1 mm/min.
From the experiments, the following results were obtained.
1) All most in all of the cases, when the condensation pressure was increased, the compressive strength was correspondingly increased. At the same time, the less the amount if mercury was used, the greater the compressive strength was.
2) The RTL and spherical amalgam required less amount of mercury to the alloys in comparison with the pellet amalgam.
3) Comparing with conventional amalgams. the RTL amalgam will produce a higher compressive strength under the same pressure(㎏/㎠).
4) The RTL amalgam is enough to to obtain a sufficient compressive strength under a light condensation pressure.