국제표준규격에 따른 치과용 석고의 물성 시험

Abstract

The purpose of this study was to examine the dental gypsum products according to the international standard(ISO 6873:1998). We tested imported Hi-Keseton, Crystal Rock, Fuji Rock, Resin Rock, Die Keen and domestic New Diastone. They were characterized as setting time, linear setting expansion, compressive strength and reproduction of detail. Setting time could not be determined to meet the requirement because not all products inscribed their own setting time in instruction. All products satisfied the requirements of linear setting expansion and compressive strength. However, no products classified type 5 from type 4 in spite of the revision of the international standard at 1998. It was found that Crystal Rock and Die Keen are suitable to type 5 for higher linear setting expansion than 0.16%. It also can be seen that not all improved stones showed higher compressive strength than these of dental stones. Reproduction of detail was tested using domestic elastomeric impression material(Perfect F, Handae Chamical, Korea). All products reproduced the 50μｍ line completely on their surface. Dental stones could not reproduce the 20μｍ line, while improved stones showed discontinuous line except Resin Rock and Tuff Rock which are contained resin in order to improve hardness and abrasion resistance.