A study of the "thixotropic" property of elastomeric impression materials

Shear-thinning, the decrease in the apparent viscosity of an impression material under a shear load, is a characteristic of many elastomeric impression materials and improves handling properties. However, it is unknown whether the subsequent viscosity of such material continues to be lower. This study compared the apparent viscosities of five elastomeric impression materials under two conditions. One group of the materials was manually spatulated and injected through an impression syringe before being tested; the other group of materials was manually spatulated only. It was found that the viscosities of these materials were not affected by the shear load applied during syringing.