Purpose Metal implants have a significantly higher elastic modulus than bone, which can lead to difficult osseointegration. One way to adapt them is to use porous structures, but these can lead to an increase in the corrosion rate and the release of increased amounts of metal species into the human body. The purpose of this article is to study the kinetics of Ti species dissolution into the human body. Design/methodology/approach This work focused on the spontaneous release of Ti species from a 3D printed gyroid structure of the beta alloy TiNb25Ta4Sn8. The dissolution kinetics were monitored by exposure tests in a physiological saline solution environment with the addition of fluoride (PSF) and minimum essential medium (MEM) followed by Ti determination by electrothermal atomic absorption spectrometry (ET-AAS). Findings The dissolution rate from the low-grade passive layer in the fluoride environment is controlled by cathodic oxygen reduction. In a fluoride-free environment, the quality of the passive layer is high and dissolution is not dependent on the oxygen content in the environment. Numeric simulations confirmed a sufficient rate of Ti excretion from the bloodstream. The corrosion rate is sufficiently low (215 nm.a-1) even in the more aggressive fluoride-containing environment and does not compromise the mechanical properties and functionality of the implant for a lifetime of 30 a. Originality/value This work dealt a novel beta alloy TiNb25Ta4Sn8 using processing by modern 3D printing technology into a gyroid structure, which provides the most isotropic mechanical properties of all porous structures.
Stoulil et al. (Wed,) studied this question.