WIT Press

Transient And Residual Thermal Stress In Porcelain-fused-to-metal Dental Crowns

Price

Free (open access)

Paper DOI

10.2495/CP980251

Volume

21

Pages

10

Published

1998

Size

1,121 kb

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