Toxicological aspects of soluble titanium – a review of in vitro and in vivo studies

Owing to the widespread use of titanium dioxide (TiO2) in various food, household and cosmetic products and in industry, the number of publications concerned with the potential toxic effects and health risks related to this substance in both bulk and nano form is steadily increasing. On the other hand, there is also a third form of titanium, ionic, which is produced by the biodegradation of Ti alloy implants. Thus, the growing population of implant recipients should raise concerns about the impact of soluble Ti on human health. Today, the mechanism of this metal's action on the human body is still not fully understood. This review aims to explore the health risks associated especially with long-term use of titanium implants. The paper provides an analysis of data available from the last 10 years concerning investigations of the adverse effects of Ti ions, including in vitro models of various tissues, in vivo studies of implant corrosion in animals and humans, and potential pathomechanisms of the adverse health impact induced by soluble titanium.