Abstract
The study was conducted to evaluate the effect of accelerators on the compatibility of dental stones with agar impression material. A dental stone without any additives (pure alpha calcium sulfate hemihydrate) was mixed with the aqueous solution of potassium sulfate, Rochelle salt and sodium chloride at different concentrations, and the slurry was poured on 10% agar gel. After setting, the surface roughness of the set stone in contact with the agar was measured. The surfaces were also examined using an X-ray diffractometer and a scanning electron microscope. In addition, the setting time of these stones was measured. The surface roughness of the set stone on the agar decreased as the concentration of the accelerators increased. A significant positive correlation was found between the surface roughness and the setting time. The diffraction X-ray intensity of the calcium sulfate hemihydrate on the stone surface decreased as the concentration of the accelerators increased. A significant positive correlation was found between the intensity and the surface roughness. The diffraction X-ray intensity of the calcium sulfate dehydrate on the stone surface increased with the concentration of the accelerators. A significant negative correlation was hoted between the logarithm of the intensity and the surface roughness. The surfaces of the set stones with the accelerators mostly consisted of very fine and needle-like crystals.
