Abstract
In order to accumulate the fundamental data for discussing the shrinkage in dental castings, the density of pure gold, silver and copper was measured at a temperature ranging from room temperature to about 1400℃, by using the apparatus which was based on the Sessile drop method. Thermal shrinkage in liquid, during freezing, and in solid state were determined individually from the temperature dependence of density measured under a condition as free from surrounding materials as possible.
The decrease of volume during freezing were 5.2% for gold, 5.0% for silver, and 4.9% for copper, respectively. From these conclusions the shrinkage in dental castings was discussed throughly.
