Dental mill blank of a porous zirconia material containing oxides of Tb, Er and Cr, process of producing and use thereof

A process of producing a dental mill blank comprising a porous zirconia material,

• the porous zirconia material comprising Zr oxide, and Y oxide calculated as Y2O3:
• 13 to 15 wt. %,
• the porous zirconia material not comprising
• Fe oxide calculated as Fe2O3 of more than 0.01 wt. %,
• Mn oxide calculated as MnO2 of more than 0.005 wt. %, or
• Co oxide calculated as Co2O3 of more than 0.005 wt. %,
• the wt. % is calculated with respect to the weight of the porous zirconia material,
• wherein the porous zirconia material is further characterized by a biaxial flexural strength of greater than 40 MPa to 80 MPa,
• the process comprising the steps of
• providing a first zirconia powder comprising Tb oxide,
• providing a second zirconia powder comprising Er oxide in an amount of 0.5 to 12.0 wt. %,
• mixing and layering a plurality of zirconia powders including the first zirconia powder and the second zirconia powder,
• compacting the layered and mixed zirconia powders to provide a compacted zirconia mixture, and
• sintering the compacted zirconia mixture to produce the dental mill blank.