Both in vitro and in vivo studies have confirmed the superior biocompatibility of high
purity Y-TZP powders especially when they are totally purified from radioactive contents.
Zirconia ceramics are chemically inert materials and no local or systemic adverse reactions have been reported. In vitro tests showed that zirconia ceramics have similar cytotoxicity to alumina (both lower than TiO2). No cytotoxic, oncogenic, or mutagenic effects on fibroblasts or blood cells were observed and no stochastic effect or chromosomal aberrations induced by Y-TZP ceramics doped with 0.5 ppm of UO2 could be found.