Mechanical and biological characterization of the Y:TZP/TiO2 composite as a function of the titania content and the type of surface

Abstract

The objective of the study is to develop the composite Y:TZP/TiO2 for application as a dental implant and to characterize it both mechanically and biologically as a function of the titania content and type of surface. The development of this composite is an innovation, since results related to this development were not found in the literature. Another innovation of this work, which has not been proposed in previous literature studies, is the alteration of the surface of this new Y:TZP/TiO2 composite in two different ways: biomimetic coating and micro-patterned silica thin films with nanohydroxyapatite micro-aggregates. It is expected that the results will have a significant impact in the area of dental biomaterials because there is no implant in the market composed of the association of Y-TZP and titania associated with the surface modifications proposed here. The new material to be developed should result in a dental implant with improved aesthetic properties and optimized biological properties compared to the materials currently available for this purpose. Y:TZP/TiO2 powders will be produced by means of a co-precipitation route to obtain three compositions: zero (T0), 5 (T5) e 10 (T10) mol% of titania. After pressing, sintering, finishing and polishing the ceramic pellets will be approximately 12 mm in diameter and 1.0 mm in thickness. Two different types of surface will be created: a) biomimetic coating (immersion in solution with ionic composition similar to body plasma) and b) micropatterned silica thin films with nanohydroxyapatite micro-aggregates (combined methodology of sol-gel and soft-lithography). The crystalline phases (X-ray diffraction technique, XRD); shape (scanning electron microscopy, SEM); granulometry (laser scattering), specific surface area (gas adsorption) and thermal behavior of the powders will be evaluated. Different thermal cycles will be performed and the results of density (Archimedes principle) and microstructural analysis (DRX and MEV) will be taken into consideration to choose the best cycle. Properties such as elastic modulus, Poisson's coefficient, hardness, fracture toughness, biaxial flexural strength (BFS), Weibull modulus (m) and fractographic analysis (FA) will be performed for the T0, T5 and T10 groups. The groups with the different surfaces will be characterized in relation to BFS, m and FA. The surface (roughness and contact angle) and biological characterization (cells and bacteria adhesion) will be performed for all groups. It is expected that the Y:TZP/TiO2 composite with the surface modifications will have high structural reliability and better biological properties compared to the Y:TZP (T0). (AU)