has an influence on the grain size and, later, the phase stability of 3Y-TZP for dental applications.
The soft machining of zirconia blanks and subsequent high temperature sintering prevents the
stress-induced transformation from tetragonal to monoclinic and leads to a final sintered surface
virtually free of the monoclinic phase, unless grinding adjustments are needed or sandblasting is
performed. On the other hand, hard machining of fully-sintered zirconia blocks has been shown to
result in a significant amount of monoclinic phase with subsequent surface microcracking and higher
susceptibility to low-temperature degradation [86]. Recently, introducing small amounts of alumina to
3Y-TZP has produced ceramic blocks known as TZP-A. The added traces of alumina improve the
durability and stability under high temperatures and humid environments. However, this has been at
the expense of the reduced translucency of ceramic blocks [86–88].