Process for Producing a Zirconia Dental Article

A process of producing a dental ceramic zirconia article, the process comprising the following steps:

• (a) providing a radiation-curable zirconia sol A comprising nano-sized crystalline zirconia particles, crystal phase stabilizer component, liquid, a radiation-curable component, photo-initiator, optionally coloring component(s) and optionally inhibitor component(s), as described in any of the preceding claims,
• (b) processing the radiation-curable zirconia sol A as construction material in an additive manufacturing process to obtain a 3-dim zirconia gel article with an outer and an inner surface,
• (c) optionally cleaning the surface of the 3-dim zirconia gel,
• (d) applying radiation-curable zirconia sol Bx on at least a portion of the outer surface of the 3-dim zirconia gel article,
• (e) post-curing the 3-dim zirconia gel article at a temperature in the range of 35 to 80° C. or by additional light curing,
• (f) optionally soaking the 3-dim zirconia gel article with another liquid,
• (g) transforming the 3-dim zirconia gel article to a 3-dim zirconia aerogel article,
• (h) heating the 3-dim zirconia aerogel article to a temperature in the range of 400 to 800° C.,
• (i) heating the 3-dim article of the previous step to a temperature in the range of 800 to 1,100° C.,
• (j) optionally conducting an ion-exchange step,
• (k) applying a sintering step to obtain a 3-dim sintered zirconia ceramic article,
• (l) optionally removing support structures remaining from the processing step (b) from the article, if support structures are present, wherein step (l) can be conducted after any of steps (e), (g), (i) or (k).