Interfacial analysis of porcelain fused to electroformed Au substrate

Objective: The aim of this study was to investigate the interfacial elemental distribution of an electroformed Au substrate veneered with a dental porcelain. Methods: Two electroformed Au specimens were prepared in a cap-like shape of °Ö0.3mm thickness, employing an electroforming system (Ephos Galvano, Element Dental). The Au specimens were sandblasted with 100µm alumina particles and then covered with a dental porcelain (DuceraGold, Degudent). The specimens were embedded in epoxy resin, metallographically grinded/ polished and C-coated Then the specimens were studied by SEM-X-ray EDS electron probe microanalysis operating under high vacuum mode and the qualitative analysis of electroformed Au substrate and of adjacent opaque layer was determined employing area scan analysis. Then the distribution of selected elements at the metal-ceramic interface was determined by using area and line scan analysis. Results: Qualitative analysis showed that the Au substrate contained also B, C, O, N, and P while the opaque comprised of Si, O, Al, Ca, Na and K. The presence of B, C, O, N and P in the metallic substrate should be assigned to the Au-sulfite electrolyte used for the electroforming process. Elemental imaging did not show any concentration gradients at the interface, due to absence of metallic elements capable of oxidazing. Conclusions: Electroformed Au-substrates contain also elements from the solution used in the electroforming procedure. The absence of elemental concentration gradients at the interface should be attributed to the limited ability of electroformed crowns to develop chemical bonding with porcelain.