Characterization of 3Y-TZP/TiO2 hybrid experimental dental ceramics

Abstract

The addition of titania to zirconia dental implants has been considered a promising choice to improve its bioactivity. This study aimed to evaluate the effect of different sintering conditions on the microstructure, density, optical properties and flexural strength of a 3Y-TZP/TiO2 dental ceramic based on zirconia with two different titania contents (7.5 mol% and 12.5 mol%). 3Y-TZP/TiO2 ceramic powders were synthesized by coprecipitation, uniaxially pressed and sintered at six different sintering conditions. Microstructural analysis of the sintered samples was performed by scanning electron microscopy and X-ray diffraction. Optical properties were measured using a spectrophotometer. The density was determined by Archimedes principle. Flexural strength was estimated by the biaxial flexure device. The microstructure and flexural strength of the 3Y-TZP/TiO2 dental ceramic with 7.5% and 12.5 mol% were affected by the sintering conditions. Sintering the specimens at 1460 °C for 2 h increased the grain size and significantly decreased the flexural strength of 3Y-TZP/TiO2 dental ceramic. The interaction (titania content x sintering conditions) affected the relative density and optical properties. A relative density greater than 98% was achieved for the T7.5 groups (sintered at 1260 °C/1 h, 1300 °C/1 h and 1300 °C/2 h) and for the T12.5 groups (sintered at 1260 °C/1 h, 1260 °C/4 h, 1300 °C/1 h and 1300 °C/2 h). The highest values of L*, a* and b* were respectively 87.2 (T7.5 group sintered at 1460 °C/2hs), 4.3 (T12.5 group sintered at 1300 °C/2hs) and 15.8 (T12.5 group sintered at 1300 °C/1 h). The material developed with 12.5 mol% of titania and sintered at 1300 °C/2 h showed high densification, flexural strength of 670 MPa and has good potential to be used in dentistry.