Evaluation of Some Physical Properties of Die Stone Made From Local Raw Gypsum Material

Abstract

Aim: The aim of this study was to prepare die stone material by dehydration of the local natural raw gypsum in boiling with 30% calcium chloride solution , and then evaluated some physical properties of this prepared die stone. Materials and methods : The values of some physical properties of the pre-pared die stone in boiling with 30% calcium chloride solution which are water/powder ratio, setting time, and compressive strength were compared with that of three types of gypsum products commer-cial die stone, Elite type III dental stone and Iraqi plaster. The data were collected , mean and standard deviation were determined. Statistically, (ANOVA) and Dunnett Pairwise Multiple Comparison test were carried out to determine the significant differences at p≤ 0.05 Results: Results showed that there were no significant differences between the locally prepared die stone and the commercial one at p≤ 0.05 in water/powder ratio and setting time values, but it was significant difference in compressive strength. But there are a significant difference between the physical properties of the locally prepared die stone and Elite type III dental stone and Iraqi plaster. Conclusions: The results showed the physical properties of the locally prepared die stone approach the physical properties of the commercial product according to the recommendation of ADA for gypsum products.

Keywords

• gypsum
• die stone
• physical properties