Unlike metals, titanium very rarely causes allergic reactions. Hypersensitivity to titanium is caused by oxidised titanium particles that form after implantation. These particles can trigger inflammatory reactions in the implant environment (see figure), which in severe cases can lead to the loss of the implant. In this process, the role of macrophages is the most important, as these cells help phagocytose the aggregated titanium oxides and thus “clean up” the implant environment.

In the laboratory test, we measure the proinflammatory cytokine response of cells (monocytes and macrophages) isolated from blood in the presence of titanium oxide. The levels of TNF-α and IL1-β cytokines following titanium oxide stimulation are measured.