| Abstract: | Setting time, water sorption, solubility, dimensional change, hardness, tensile strength, compressive strength, bending strength, and Young's modulus of resin model materials and gypsum model materials were determined. These results are following: 1) Setting time of Goldex is in general the same as that of dental plaster, and setting time of Alpha-Die and that of Dicodur are the same as densite type stone. But setting time of Rock Model is very long, that is, ten times as long as that of densite type stone. 2) Water sorption and solubility of gypsum model materials are larger than those of resin model materials. Solubility of Dicodur is larger in comparison with the other resin model materials. 3) During setting, all of gypsum model materials expand but all of resin model materials contract. The absolute values of dimensional change of Rock Model and of densite type stones are the same, but smaller compared with those of other materials. 4) The value of knoop hardness of resin model materials is between that of plaster of Paris and that of hydrocal type stones. 5) In comparison with densite type stone, resin model materials are 2.5 to 5.0 times in tensile strength, the same in compressive strength, and 1.5 to 2.3 times in bending strength. 6) Young's modulus of resin model materials is 1/3 to 1/5 as much as that of densite type stones. |
