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

• Published in: Dental materials 2020-11, Vol.36 (11), p.1418-1429
• Main Authors: de Paula Miranda, Ranulfo Benedito, Leite, Tayná Paula, Pedroni, Ana Clara Fagundes, Marques, Márcia Martins, de Lima, Nelson Batista, Marchi, Juliana, Cesar, Paulo Francisco
• Format: Article
• Language: English
• Subjects: Accelerated life tests; Accelerated tests; Biological behavior; Biological properties; Biomedical materials; Density; Dental implants; Dental materials; Dental restorative materials; Dentistry; Differentiation; Flexing; Flexural strength; Mechanical properties; Microstructural analysis; Microstructure; Mineralization; Nodules; Optical properties; Osteoblastogenesis; Osteoblasts; Parameters; Scanning electron microscopy; Sintering; Sintering (powder metallurgy); Sintering temperature; Temperature; Tetragonal zirconia; Tetragonal zirconia polycrystals; Titania; Titanium dioxide; Weibull modulus; X-ray diffraction; Y-TZP; Yttria-stabilized zirconia; Zirconia; Zirconium dioxide
• ISSN: 0109-5641; 1879-0097
• DOI: 10.1016/j.dental.2020.08.014

•The composite showed enhanced cell proliferation rate when compared to Y-TZP.•Addition of 12.5% of titania to Y-TZP resulted in formation of more mineralization nodules compared to the control.•The composite showed no perceptible color differences when compared to Y-TZP.•3Y-TZP/TiO2 showed estimated failure probability 4.7% after 5 million cycles at a stress level of 50 MPa. The aims of this study were: 1) to evaluate the effect of sintering temperature on microstructure, density and flexural strength of a 3Y-TZP/TiO2 composite containing 12.5 wt% of TiO2 compared to 3Y-TZP specimens (control); 2) to compare 3Y-TZP with the experimental 3Y-TZP/TiO2 composite, both sintered at 1400 °C, with respect to the following parameters: optical properties, characteristic strength, Weibull modulus, fatigue behavior, induction of osteoblasts proliferation and differentiation (mineralization nodules formation). The 3Y-TZP and 3Y-TZP/TiO2 powders were uniaxially pressed and sintered at 1200 °C, 1300 °C, 1400 °C or 1500 °C for one hour in a furnace. The microstructural analysis consisted of X-ray diffraction and scanning electron microscopy. The density was measured by the Archimedes' principle and the flexural strength was obtained by the biaxial flexure test. The optical properties were measured using a spectrophotometer operating in the visible light wavelength range. The step-stress accelerated life testing was performed by the pneumatic mechanical cycler and the biological behavior achieved by using osteoblast-like cells (Osteo-1 cell line). Tetragonal zirconia was identified in all groups and cubic zirconia was identified only at 3Y-TZP group. The addition of TiO2 decreased the values of density and flexural strength of the composite 3Y-TZP/TiO2 in relation to 3Y-TZP regardless of the sintering temperature. The color difference between the two materials was not significant regarding L*a*b* parameters. The composite showed higher probability of failure, and induced higher proliferation and differentiation than control. The composite developed have good aesthetic and biologics properties. However, its microstructure and mechanical properties need to be improved for future dental implant applications.