Aging behavior of Y-TZP with bioglass addition and its impact on the flexural strength and osteoblastic cell response

Y-TZP containing Ca(2)P(2)O(7)are promising bioceramics with potential applications in dental implants and dentistry. These ceramics were developed by the introduction of a refractory sol-gel derived CaO-P2O5-SiO(2)bioglass into Y-TZP; Ca2P2O7, and ZrSiO(4)phases were formed in situ after sintering. The aging process of Y-TZP with different glass additions was studied. The effect of glass addition on the flexural strength and osteoblastic cell response of non-aged and aged Y-TZP was investigated. Y-TZP exhibited the most pronounced tetragonal (t) to monoclinic (m) transformation of zirconia (ZrO2) during aging; the addition of glass contents between 5 and 20 vol% improved the aging resistant of Y-TZP. Y-TZP flexural strength markedly decreased with increasing aging time; in contrast, the ceramics with glass did not alter their flexural strength upon aging. An increase in the Ca(2)P(2)O(7)content with increasing glass up to 10 vol%, promoted both the cell viability and the osteogenic differentiation of UMR-106 cells on non-aged and aged samples. The high micro-roughness of Y-TZP with 20 vol% glass after aging, limited the proliferation and the osteogenic potential of the cultures. Y-TZP with 10 vol% glass had the best combination of properties in terms of flexural strength and osteoblast cell response.