An evaluation of elastomeric impression materials based on surface compressive strength.
The setting times of seven commercially available elastomeric impression materials were determined using Wilson's reciprocating rheometer at temperatures 23 +/- 0.5 or 32 +/- 0.5 degrees C. The surface compressive strength and depression of these materials after setting time were measured using a rheometer (Fudoh). Each material was mixed according to the mixing proportion (base/accelerator or catalyst ratio) recommended by the manufacturer. The surface compressive strength and the depression of each material were measured by using a method which pressed the material to the edge of a sensitive rod (2.0 mm in diameter) connected to a load cell. In the case of silicone impression materials (additional type) at a temperature of 23 +/- 0.5 degrees C, the surface compressive strength and the depression of these materials were extremely stable after the setting time. However, the surface compressive strength of other materials except additional type materials increased markedly after setting time and the depression corresponding to the surface compressive strength decreased. These increased largely with the increase, in pressing speed to the sensitive rod. At 450 s from the setting time of all materials, there was an adequate correlation (r = 0.84) between measured values and theoretical values derived using the theory of elasticity.
Omori
K
K
Department of Dental Materials Science, Kagoshima University Dental School, Kagoshima, Japan.
Arikawa
H
H
Inoue
K
K
D019245:Compressive Strength; D003760:Dental Impression Materials / Q000737:chemistry*; D004548:Elasticity; D020724:Elastomers / Q000737:chemistry; D004987:Ethers / Q000737:chemistry; D008422:Materials Testing; D012212:Rheology / Q000295:instrumentation; D012828:Silicones / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors
D003760:Dental Impression Materials; D020724:Elastomers; D004987:Ethers; D012828:Silicones; D013440:Sulfides; C032915:polysulfide