In vivo measurements of thermal diffusion through restorations of various materials.

Temperature diffusion was monitored through in vivo restorations with and without bases 0.5 and 1 mm thick. Temperature diffusion was highest through amalgam restorations and slowest through unfilled resin restorations. The rate of diffusion through composite resins and silicate cement fell between the extremes. Bases of both zinc phosphate cement and zinc oxide-eugenol cement reduced the rate of temperature change on the floor of the cavity beneath amalgam restorations. The temperature change was generally less under the 1 mm base than the 0.5 mm base. Bases used beneath the nonmetallic restorations did not reduce the magnitude of temperature change on the cavity floor.