Differences Among Zirconia Ceramics

Are there differences among zirconia ceramics?
Differences among zirconia ceramics can occur with the level of purity of zirconia; grain size, trace elements and stabilizing compounds; and consistency of formulation. Differences can exist in shrinkage from batch to batch because of differences in the coefficient of thermal expansion (CTE).
Vsmile zirconia milling disc are based on high-quality pure nanometer powder comparable to Tosoh zirconium granulate. it is tailored to the requirements of Vsmile R&D by the producer.that guaranteed our zirconia discs can available to achieve the highest possible quality and esthetics.
The zirconium oxide is further processed in a multi-stage manufacturing process,the initial moulding is done by uniaxial pressing,result is a very homogenous disk with high precision,then the blanks are pre-sintered in microprocessor controlled kilnseach blank is given its own shrinkage factor.This gives us the opportunity to offer you one of the best dental zirconia materials on market today.
Zirconia substructures have high flexural strength, 900-1200 MPa, but what is the flexural strength of the zirconia/porcelain system?
Flexural strength is typically performed on a three-point bend specimen and is a function of relative thickness of the zirconia and overlaid ceramic, but it would not exceed the flexural strength of the zirconia.

Does zirconia ceramic degrade in strength intraorally in 5-10 years?

Yes, all-ceramic materials degrade in strength over time - some more than others. Vsmile ST Zirconia ceramic  has an initial flexural strength of over 1200 MPa, so even if it degrades 5-10% or more, it is still significantly stronger than other ceramics.