Compressive strength and setting temperatures of mixes with various proportions of plaster to stone

The compressive strength and setting temperature of different proportions of stone to plaster were measured. The water/powder ratio was 40:100 for all combinations. According to the experimental data, samples of stone to plaster in the ratios of 1:1, 1:3, and 1:4 gave an increased compressive strength of 10.3 MPa compared with the strength of plaster alone (8.3 MPa), possibly because of the low amounts of dental stone in the mix. The lowest amount of heat generated (lowest setting temperature) was recorded by the samples made with the ratio of stone/plaster equal to 1:1, which gave a setting temperature of 43 degrees C. Thus, the mix made with this ratio of stone to plaster may be the material of choice for filling the upper half of the flask during complete denture construction.