To determine the thermal expansion of a porcelain (VM9) and tetragonal zirconia (Y-TZP) as well as the deflection upon re-heating and cooling of a bilayer fabricated from these two materials after slow and rapid cooling during initial fabrication.

Two methods for measuring shear strengh of the porcelain-metal interface, a rod/disk-push test and a cube/cube-push test, were compared using the same metals and porcelain material. Both types of specimen showed evidence of complex stress distribution at the interface during loading and fracture line located mainly in the opaque porcelain layer. Both methods were thus mainly a test of the “strength” of the porcelain at the interface.