The elastic modulus of soft denture liners.

Abstract

Under certain circumstances, e.g., when treating "denture sore mouth" or after the provision of immediate dentures, dentures may be lined with soft rubberlike materials which have Young's moduli within the range congruent to 10(5) N m-2. Measurement of the compression modulus Ec of such soft liners is described and Gent and Lindley's method of calculating Young's modulus E was evaluated. It was established that the Young's modulus may be calculated using: Ec = E(1 + 2kS2), where k = 1 for soft rubbers, and for disks S is a shape factor and = radius/2 X thickness. It is also shown that Young's modulus is a linear function of log(rate of strain) for both tension and compression measurements. When gellation has occurred subsequent to mixing there is an increase in Young's modulus due to loss of ethanol. When immersed in brine the elastic modulus remains approximately constant from a day to a week or longer.