Layered structures address the competing needs of systems with dissimilar requirements on different surfaces. In all- ceramic dental crowns, the exterior must be aesthetic and the interior must be strong and the combination must be fatigue resistant. Current structures are prepared by creating a strong core and then, through a series of labor-intensive steps, layering the porcelain veneer onto the core. If the core and veneer could both be independently fabricated using modern shaping technologies (computer aided design and manufacturing or solid freeform fabrication) and then joined, both core and veneer could be optimized for performance, inevitable shaping damage could be minimized, and the labor intense steps dramatically decreased. The individually fabricated layers could be fused using a glassy join, creating a join layer holding the core to the veneer. During the joining process, atomic mixing of atoms or ions across the interface between the layers (interdiffusion) occurs. The degree of interdiffusion influences the mechanical properties of the combined layer system. While this technology has been applied in other fields, including glass to metal seals, fuel cells, and hermetic electronic packaging, but, to our knowledge, performance of glass joins has not been systematically evaluated for applications where the layers are subjected to fatigue loading. The overall objective of this research is to investigate the effects of glass joins on performance and lifetime of layered ceramics systems. The demonstration model will be layered ceramics used in dental crowns and the fundamental understanding of the effects of glass joins on performance and lifetime has relevance to multiple other applications of layered ceramic systems and could provide insight into creation of damage-resistant compositionally graded systems. ? ?
| Saied, M A; Lloyd, I K; Haller, W K et al. (2011) Joining dental ceramic layers with glass. Dent Mater 27:1011-6 |
