Zirconia crowns are the hardest and strongest type of ceramic crown available.
The capacity of zirconium to be modified according to the set of teeth it will be placed alongside with is very important. Zirconium crown will not only replace a tooth but it can be shaped so that it will look better than the one it will be replacing.
‘Monolithic’ (solid) crowns made entirely of Zirconia, which are computer designed and milled from a single uniform block on a CAD/CAM machine. The advantage of these is that they are extremely hard and long-lasting, and don’t require much tooth structure to be removed (compared to most ceramic crowns) as the material is very strong in thin sections. However, due to the dense singular material, it can be hard to get an excellent shade match and they have minimal light-reflective properties.
Zirconia core-only crowns. This is where Zirconia is only used to build the core (inside part) of the crown that sits over the natural tooth, and standard transparent porcelain is then layered over the top to create and build up the rest of the crown. These types of crowns are not as strong as full zirconia, but have translucent properties that more closely match a natural tooth.