승온 속도에 따른 치과용 아가 인상재의 열적 거동

Abstract

Agar-agar has been used for impression taking of prepared cavity and abutment on teeth. Their liquefaction and setting are highly dependent upon their thermal properties. Normally, liquefying and storage temperature is 100oC and 65oC, respectfully. But the heating time and temperature are dependent on the mass of materials and heating rate. The purpose of this study is to evaluate the relation between heating rate and liquefying temperature owe to support the data for using rapid heating unit, such as microwave. One commercial agar impression materials (Colloid 21, Clark Co., Japan) was selected. Differential Scanning Calorimetry Analysis was conducted to evaluate the thermal behavior using DSC (STA 409PC, Netzsch Co., Germany), employing the following experimental conditions: sample weight = 20 mg, scanning range = 30oC~300oC, heating rate = 1 oC/min, 2 oC/min, 5 oC/min, 10 oC/min, 20 oC/min and 50 oC/min. On-set and end point temperatures of endothermic area and endothermic energy per mass were recorded. It was concluded that it need higher temperature to get perfect liquefaction of agar impression materials when we use rapid heating unit (p<0.05) and there is no significant difference in the total energy between tested groups (p>0.05).