Effect of titania addition and sintering temperature on the microstructure, optical, mechanical and biological properties of the Y-TZP/TiO2 composite

Abstract

Objective. The aims of this study were: 1) to evaluate the effect of sintering temperatureon microstructure, density and flexural strength of a 3Y-TZP/TiO2composite containing12.5 wt% of TiO2compared to 3Y-TZP specimens (control); 2) to compare 3Y-TZP with theexperimental 3Y-TZP/TiO2composite, both sintered at 1400°C, with respect to the followingparameters: optical properties, characteristic strength, Weibull modulus, fatigue behavior,induction of osteoblasts proliferation and differentiation (mineralization nodules forma-tion).Methods. The 3Y-TZP and 3Y-TZP/TiO2powders were uniaxially pressed and sintered at 1200°C, 1300°C, 1400°C or 1500°C for one hour in a furnace. The microstructural analysis con-sisted of X-ray diffraction and scanning electron microscopy. The density was measured bythe Archimedes’ principle and the flexural strength was obtained by the biaxial flexure test.The optical properties were measured using a spectrophotometer operating in the visiblelight wavelength range. The step-stress accelerated life testing was performed by the pneu-matic mechanical cycler and the biological behavior achieved by using osteoblast-like cells(Osteo-1 cell line).Results. Tetragonal zirconia was identified in all groups and cubic zirconia was identified onlyat 3Y-TZP group. The addition of TiO2decreased the values of density and flexural strength ofthe composite 3Y-TZP/TiO2in relation to 3Y-TZP regardless of the sintering temperature. Thecolor difference between the two materials was not significant regarding L*a*b* parameters.The composite showed higher probability of failure, and induced higher proliferation anddifferentiation than control. Significance. The composite developed have good aesthetic and biologics properties. However, its microstructure and mechanical properties need to be improved for future dental implant applications.