Abstract
To improve the surface quality and roughness of die stone poured into the alginate hydrocolloid impression, the surface of impression was pretreated with the concentrated calcium chloride solution, ranging from 5 to 40% by weight, for 30 seconds.
The SEM observation and the surface roughness measurement for the stone surfaces which was set on the modified impressions revealed that the dihydrate crystals grew more densely at the surface than that for the stone surfaces which were produced from the impressions not pretreated or pretreated with the conventional fixing solutions, 2% potassium sulfate solution or 2% zinc sulfate solution, and that the excellent smooth surface comparable to the stone surface from addition silicone impressions was obtained by the pretreatment with 10-20% calcium chloride solution.
It was suggested that the die stone poured into the alginate hydrocolloid impressions pretreated with the new fixing solution was availabe as a working model in dental pracitice.
