1Assistant Professor Department of Dental Technology, Gimcheon University, 214 Daehak-ro, Gimcheon-si, Gyeongsangbuk-do, 39528, Korea
2Associate Professor, Department of Dental Technology, Gimcheon University, 214 Daehak-ro, Gimcheon-si, Gyeongsangbuk-do, 39528, Korea
Online published on 16 October, 2018.
Though phosphate-bonded investments are often used for casting dental alloys, studies on their setting expansion are insufficient. This study was conducted to investigate differences in setting expansion of different types of phosphate-bonded investments and proportions of mixing solution..
The investment solution was mixed first by hand and then using a vacuum mixer, and the rate of setting expansion of the four groups of investment was measured up to 120 minutes by inserting the investment material into a curing inflator and tightening the dial indicator (2046S, Mitutoyo, Japan)..
The results of the setting expansion test show that the two types of dental casting phosphate-based investments had higher rates of setting expansion when a higher the ratio of stock solution was used in the mixing solution (p<.0001), and all four groups showed increased rates of setting expansion as time passed..
When using dental casting phosphate-based investments, they should be kept at the room temperature and mixed with the ratio of mixing solution recommended by the manufacturer depending on the types of precious and non-precious metal alloys used.
Setting expansion, mixing ratio, phosphate-bonded, dental investments, vacuum mixing
