Are zirconias of today different?

The advantages of ceramic materials are generally considered to be their tooth-like translucent appearance, their good biological compatibility in direct contact with the gingiva and a wear pattern that is comparable to that of enamel. These criteria are usually met by lithium silicate ceramics, which are indicated for veneers, tabletops, single crowns and small anterior bridges. If we wish to expand the indication range and integrate larger restorations in the posterior region, this objective is only achievable with zirconia ceramics. However, the higher fracture strength of zirconia is obtained at the expense of an opaque, less tooth-like appearance. This fact was initially not disturbing because the opaque framework was veneered with feldspathic ceramics. Since it has become technically possible, using the CAD/CAM process, to produce not only frameworks made of zirconia, but also complete restorations with occlusal surfaces, the high opacity of zirconia is no longer desirable from a clinical point of view. Developments in recent years have aimed to develop zirconias with the above-mentioned properties of silicate ceramics, which include combining translucency, biocompatibility, a tooth-like wear pattern with higher fracture strength and the possibility of CAD/CAM processing. These efforts have resulted in the development of different types of zirconia.