Does Layered Zirconia Fracture Easily?
Short answer, NO!
Long answer, when it first came out, some laboratories handled it wrong and fabricated a few units poorly, going against all of the porcelain veneering rules they have used for 75 years, (PFMs) and giving layered zirconia a bad name.
Labs thought zirconia was bulletproof. Nope!
It’s really simple! Veneering porcelain needs to be supported.
When you fabricate a PFM, the substructure is waxed to full contour then cut back 1.5mm all around and occlusally for the ideal support of the veneering porcelain. If veneering porcelain is close to 2mm thick it leaves the supporting protection of the substructure and is prone to cracking, chipping, and fracturing.
The exact same rules apply when layering or veneering zirconia. The technique is a little different but the theory is the same. Design the tooth to full contour (virtually), then hit the cutback button and it immediately cuts the crown back 1.5mm in preparation for the veneering porcelain.
The unbreakable law for veneering porcelain has always been keep it within 1.5mm for safety and strength.
Does layered zirconia fracture easily? NO! Not when it is fabricated correctly.