Elastic moduli and visco-elastic relaxation.

The elastic moduli of dental biomaterials are discussed in relation to the various intrinsic and extrinsic factors that can influence the magnitude of these parameters and hence the extent of modulus-matching with oral tissues. The time-dependent visco-elastic response is shown to be an important feature of both natural and many synthetic biomaterials. This modifies the stress magnitudes sustained in the restored unit, especially when polymeric chains or networks are a major constituent of the overall structure. An understanding of both moduli and visco-elasticity is valuable in the appraisal of clinical performance of biomaterials.