Effect of 64S bioglass addition on sintering kinetic, flexural strength and osteoblast cell response of yttria-partially stabilized zirconia ceramics

Abstract

A quantity of 3 mol% yttria-partially stabilized zirconia (Y-TZP) with 10.5 and 19.9 vol% 64S bioglass compacts was sintered at different temperatures up to 1500°C. The influence of 64S glass addition on the sintering kinetic, flexural strength, and osteoblast cell response of Y-TZP ceramics was investigated. The addition of 64S glass increased the initial sintering rate through the decrease in the activation energy and the increase on the order of diffusion with respect to those previously reported for Y-TZP. Y-TZP at 1500°C exhibited the highest flexural strength. Within Y-TZP ceramics with 64S additions, a maximum flexural strength occurred for 10.5 vol% 64S at 1400°C, its flexural strength was able to approach that of Y-TZP at 1500°C. The polished sintered surfaces became rougher as the 64S content increased. Cell viability experiments on the less nanoroughness Y-TZP and Y-TZP with 10.5 vol% 64S surfaces revealed their good biocompatibility; on the contrary, the high level of nanoroughness of Y-TZP with 19.9 vol% 64S significantly reduced cell survival. However, the matrix mineralization was not adversely affected by the surface roughness; larger amounts of calcium phosphate phases on Y-TZP-19.9 vol% 64S surfaces appeared to promote the osteogenic potential of UMR-106 cells.