The absorbed titanium can accumulate in other organs in the body as shown in the animal and cultured cell experiments. In addition, Feng et al. reported that nanoparticles can pass through the blood-brain barrier (BBB) and may be toxic to the central nervous system (CNS). The testing methods still have limitation and further studies need to be performed, but the neurotoxic nanoparticles including titanium particles is indicated, which requires a development of safety assessment systems.

In case of the particles from corrosion process accumulate in the gingival sulcus, corrosion products can diffuse into adjacent tissues and cause the blue-gray pigmentation of gingiva and root dentin. There are various studies on the tissue behavior and long-term effect related to amalgam tattoo; however, the similar studies on titanium tattoo are rare. A study on pigmentation of human teeth and gingiva evaluated the composition of common metal used in dental alloy, including titanium, as reported by Venclikova et al. Authors indicated the detection of titanium in tissue around an implant which had the presence of oral mucosa pigmentation. The titanium needle-like deposits were found in the extracellular matrix around fibroblasts and macrophages. More recently, Taylor et al. report two cases of titanium tattooing associated with a system of titanium implant and zirconia abutments. In the two cases, the dark pigments were found after the failure of the zirconia abutment. The biopsy results identified the particulate material dispersed within the tissue was titanium. Within the little amount of report and study on the titanium tattooing, it can be assumed that the releasing of metal particle into gingiva tissue can lead to the formation of the dark color pigmentation, which has the considerable influence on the esthetics, and this phenomenon seems to be related to the fracture or loosening of restoration abutment, when a large amount of metal can be released at a same time. With the development of titanium dental implant in the present, the titanium tattooing is a significant topic that needs more report and study due to its influence on the success of dental implant.