Interfacial analysis of porcelain fused to high-palladium alloy with different observation methods

Abstract

Background/purpose In a previous fractural study of implant-supported crowns, it was found that the palladium−silver crowns possessed the highest fracture force. The ceramic–metal interface was examined to explain its high resistance to fracture. Materials and methods Palladium−silver crowns with the morphology of a maxillary second premolar were prepared following standard dental laboratory procedures. Crown specimens were compressed vertically in the center of the occlusal surface until fracture, using a universal testing machine. The fractured surfaces were examined using scanning electron microscopy combined with energy dispersive X-ray spectroscopy to determine the failure mode. The ceramic–metal interface of the crown was examined with electron probe microanalysis. Additionally, sheet specimens with a dimension of 10 × 9 × 4 mm 3 were prepared to examine the surface morphology and composition of palladium−silver alloy after oxidation and porcelain-fused-to-metal firing cycles. Results The average fracture force was 1425 ± 392N. Analyses with scanning electron microscopy combined with energy dispersive X-ray spectroscopy revealed that the failure mode was cohesive within the ceramic layer. Electron probe microanalysis micrographs indicated that Sn and In were found to distribute only on the alloy side of the ceramometal crown. Energy dispersive X-ray spectroscopy analysis and electron probe microanalysis micrographs confirmed that ZnO had diffused into the ceramic phase. Conclusion In 2 O 3 , SnO 2 , and ZnO were found along the interface; the presence of these oxides at the boundary promotes ceramic–metal adhesion, and this resulted in cohesive failure of the ceramic layer. ZnO was found to diffuse into the ceramic phase, and it is suggested to be beneficial for high fracture resistance in the present study.

Oxide layer characteristics and interfacial analysis of porcelain fused to high-gold alloy using multitechnique analysis methods

“…Ten ceramometal crowns and six sheets of Au–Pt alloy were fabricated according to the manufacturer’s instructions, involving five standard dental preparation stages (Figure 1). 17 For brevity, the detailed preparation stages and observation methods presented in the Pd–Ag article are not repeated here 17 Wax patterns were prepared, sprued, and invested.…”

“…Schematic illustration of procedures for fabrication of rectangular specimens and crowns 17 . Corresponding characterization is shown on the right side.…”

“…Compressive fracture tests of ceramometal crowns were performed using a universal testing machine 16, 17Figure S1 17 in the supplementary material online photographically shows a custom-built loading apparatus following the design of Torrado et al 15 . The upper member of the apparatus consisted of a 15-mm-diameter hardened stainless steel shaft that connected to the end of the loading part of the universal testing machine.…”

“…The following are the supplementary data related to this article:

Figure S1Frontal view of loading apparatus for testing crown 17

Figure S2Representative SEM micrographs and corresponding EDX element profiles of fracture surface on alloy side: (A) upper; (B) middle; (C) lower.

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