Flexural strength of two electro-plated dental ceramics

This study aimed to investigate the influence on flexural strength of electro-plating two dental porcelains, Vita Omega and Vita Omega 800. The porcelains were treated in accordance with the manufacturer's instructions, and the specimens were produced following the ISO 6872 standard for rectangular bars. Specimens were divided into three groups, of which none, one, or three of the surfaces were plated with a thin layer of gold. Flexural strength was tested with a three-point bending test. Ten specimens were tested for each combination of porcelain and plating, for a total of 60 test pieces. For both porcelains, a significantly higher flexural strength was found for the specimens furnished with a gold layer. The number of covered surfaces did not significantly influence the tested strength. This increase in strength is most likely due to decreased crack initiation and fracture propagation after the covering of random defects in the porcelain. A better stress distribution might also be anticipated and partly explain the results.