Residual stresses in metal-ceramic crowns.

Residual stresses in metal-ceramic crowns were examined in three different ways. First, a mathematical formula was used to calculate the stresses in the cervical part of a crown. Second, plastic models was used where the strains were measured with strains-gauges. Third, real crowns were used and strain gauges were attached on them. The results indicated that compressive stresses appeared in the porcelain-metal interface. Compressive stresses were also found on the surfaces of the crowns and tensile stresses perpendicular to the interface.