[Influence of the thickness of metal and porcelain upon metal-ceramics (author's transl)].

This paper deals with the strength of metal-ceramics and the influence of the thickness of metal and porcelain layer. The metal-ceramic specimens, 30 mm long and 10 mm wide of various each thickness, supported at each ends, were tested by bending to obtain the transverse strength. The thickness of metal layer was changed from 0.2 mm to 1.0 mm, while that of porcelain layer was changed from 0.5 mm to 1.3 mm respectively. Interaction of the thickness of metal or porcelain layer to the fixed total thickness was also investigated comparing with the results of the experiment in which the thickness of one side was constant. From the load-deflection diagram, the maximum work before breaking was surveyed and compared. Main results were as follows. 1) In case of the same total thickness of metal-ceramics, the thicker the metal layer, the greater the transverse strength, maximum work before breaking and maximum deflection. 2) When the metal thickness exceeded one half of the porcelain layer, the transverse strength increased in comparing with value of porcelain itself. 3) The maximum deflection of metal-ceramics by bending before breaking was approximately three or four times as great as that of simple porcelain. 4) The work of the metal-ceramics by bending before breaking was approximately two or three times as that of the simple porcelain. 5) It was imagined that the total strength of the metal-ceramics would be affected by the hardness of the constituent metal and boundary bonding strength.