Heat Conduction in Teeth and the Effect of Lining Materials

¹ Dental School of The London Hospital Medical College, London

The temperature changes under the lining of an amalgam-restored tooth are transient for times up to thirty seconds (the conditions likely to be of greatest physiologic interest).

It is the thermal diffusivity (thermal conductivity/specific heat x density) of the lining that is relevant to transient conditions. Measurements of this parameter show that it rates lining materials in a different order from that obtained by studying thermal conductivity; hence data on the latter property are misleading.

The differences in diffusivity between zinc phosphate and zinc oxide-eugenol linings are of less importance than variations in lining thickness. This is because the parameter governing lining efficiency is lining thickness/ diffusivity.