Abstract
In order to study the compatibility of dental stones with agar impression materials, the surface roughnesses of five commercial stones that were set against eight agar impression materials were measured.X-ray diffraction analysis and X-ray microprobe analysis were performed for each surface of the set stones to examine the surface products such as calcium sulfate dihydrate, calcium sulfate hemihydrate and syngenite, as well as the distribution of potassium.The correlation between the surface roughness and the diffraction X-ray intensities(cps)of the surface products as well as the distribution of potassium on the set surfaces were statistically analyzed.The results are summerized as follows:1)A significant positive correlation was found between the diffraction X-ray intensity(cps)of calcium sulfate hemihydrate and the surface roughness.2)A significant negative correlation was found between the logarithm of the diffraction X-ray intensity of calcium sulfate dihydrate and the surface roughness.That is, the surface of the set stones was drastically roughened when the intensity of calcium sulfate dihydrate was very low.3)Syngenite was not detected on the surface of the tested stones at 1 minute but after 24 hours following the removal from the impression.No significant correlation was found between the diffraction X-ray intensity of syngenite and the surface roughness.4)No significant correlation was found between the potassium distribution and the surface roughness.
