The unreacted hemihydrate in set dental stone was estimated quantitatively by means of specific heat measurements. With decreases in the water-to-powder ratio (W/P), increases were observed in the amount of unreacted hemihydrate in the set mass. These increases were marked in set stone with a W/P ratio less than 0.25. Furthermore, the amount of unreacted hemihydrate was higher in the interior of the dental stone than in the set surface. It is very difficult to attain a complete reaction, even with higher W/P ratios such as 0.8 in the dental mixing procedure.
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Hisatsune, K., Takuma, Y., Shibuya, M. et al. Quantitative analysis of unreacted hemihydrate in set dental stone by adiabatic calorimetry. J Mater Sci: Mater Med 6, 284–287 (1995). https://doi.org/10.1007/BF00120272
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DOI: https://doi.org/10.1007/BF00120272