Effect of microwave oven drying on surface hardness of dental gypsum products

Abstract

D entists often find it necessary to work with gypsum casts soon after separating them from impressions. Since wet casts usually have inadequate surface hardness, dentists normally must wait 24 to 48 hours before the casts are strong enough for manipulation. To save time, the microwave oven-drying technique has been suggested.’ However, the effect of microwave oven drying on gypsum products has not been thoroughly examined. The purpose of this study was to investigate and compare the surface hardness of eight dental gypsum products dried by microwave oven (1485 W, Maytag CME, Maytag Corp., Newton, Iowa) or ambient air.