4. Components for yttriated zirconia prostheses

With process optimization reaching its limit (defect size reduction becoming increasingly difficult), further gains in mechanical properties required an intrinsically better material (i.e. one with superior toughness). At the end of the eighties, zirconia (in various forms) seemed the best candidate. This article shows the advantages and disadvantages of zirconia in relation to its microstructure, with particular emphasis on the importance of its phase change (which is responsible for its good mechanical properties, but also for problems of accelerated degradation).

The concepts outlined here are equally valid for all zirconia-containing composites, even if zirconia degradation does not exhibit the same kinetics or impacts if it occurs alone or within a composite.