Author(s)

J. Lenz, M. Thies & K. Schweizerhof

Abstract

Rotationally symmetric, premolar porcelain-fused-to-metal (PFM-) crowns were heated in a porcelain furnace to barely above the ceramic's glass transition temperature (~ 600°C). After opening the furnace, local temperatures at the crown's surface were simultaneously measured with thermocouples and recorded during the cooling phase down to ambient temperature. These data were smoothened and used as input to a FE-model to calculate the internal temperature and stress distribution as a function of time. Maximum transient stresses in the veneer occurred at the surface near the crown's cusp shortly (~ 24 seconds) after opening the furnace, whereas maximum residual stresses were found

Keywords