Zirconia as a dental ceramic is a synthetic material which exists in three different crystal structures. The polymorph materials’ phases change depending ont he temperature and pressure. This transformation phenomenon is reversible. The most stable crystal structures exist in higher temperatures only. Cooling leads to furrher stress in the crystal structure of the sintered ceramincs which results and promote fracture and cracks. To avoid the rigidity, it needs stabilizing componenets like yttria (Y2O3) or other rare-earth oxides. By adding these substitutes tot he zirconia, the result is partially or fully stabilized crystal structure. Due to this „little chemical spell” ceramics with remarkable mechanical and chemical properties could be created.