Q: Do different zirconia products have different CTEs?

A: Yes, there are variations in coefficients of thermal expansion (CTE) among zirconia products as well as among overlay porcelains. Compatible systems must be used.

Q: How strong is a zirconia-based restoration when the substructure has a flexural strength of 1,200 MPa and the surface ceramic has a flexural strength of 110 MPa?

A: Zirconia is stiff. Because it does not bend easily, it helps the weaker overlaid porcelain resist fracture.

Q: What's a closed zirconia milling system and what is the benefit of an open system?

A: Open and closed architectures refer to the way scanners/design stations communicate with the mills and printers. An 'open' system provides a standardized file type and structure that can be understood by other open systems and equipment. A 'closed'-architecture (proprietary) system will only work with equipment that uses the same proprietary file types and s…

Q: With porcelain-fused-to-metal systems, ceramic bonds to the oxide layer on the metal. What does the zirconia veneering ceramic bond to?

A: Usually the overlaid porcelain bonds to a compatible porcelain wash material that is applied to the zirconia first.