Consistency, working time and setting time of elastomeric impression materials

This paper describes the development of an instrument for determining consistency, working time and setting time of elastomeric impression materials. The operating principle involves the application of a fixed compressive strain and the resulting stress is measured. This instrument has been called a Comprheometer. Temperature control is achieved by water circulation so that simulated room or open-mouth temperatures can be used. Values of consistency and working time are presented for a range of elastomeric materials at room temperature. Also, setting times determined under oral conditions are recorded.