Agar/Alginate Combined Impression Systems : Effects of Removal Time from Impressions on Surface Roughness of Stone Models

Abstract

The effects of removal time of stone models from agar impressions and agar/alginate combined impressions on the surface roughness(Ra)were evaluated between 30min and 24h after the start of stone mixing.Six agar impression materials, one alginate impression material and two dental stones were used.The Ra of stone models removed at 1, 3 and 6h was also determined on two agar impression materials which resulted large differences in Ra between 30min and 24h.The Ra of stone models removed from the impressions at 30min was larger than that of models removed at 24h.The models removed after 3h showed the minimum value of Ra.