Recently, there are more studies working on the linking of titanium implants and implant complication or failure. Wachi et al. reported that Ti ions may be involved in the deteriorating effects of peri-implant mucositis, which can develop into peri-implantitis accompanied by alveolar bone resorption. Olmedo et al. reported two cases of reactive lesions of peri-implant mucosa associated with titanium dental implants, one case was diagnosed as pyogenic granuloma and the other case as peripheral giant cell granuloma. The presence of metal-like particles in the tissues suggests that the etiology of the lesions might be related to the corrosion process of the metal structure. In a previous study, the authors found macrophages loaded with titanium particles as indicators of the corrosion process in the soft peri-implant tissue of failed human dental implants.

Assuming the implant particle can be an initiator of the peri-implantitis, many studies have been performed to approach the oral mucosa tissue’s response to titanium implant as well as implant cover screws. To determine the correlation between titanium particles and peri-implantitis, Olmedo et al. performed the exfoliative cytological test and observed particles inside and outside the epithelial cells and macrophages. Also, the experiment pointed that the concentration of implant particles in the peri-implantitis group was significantly higher than in the control group. The recent study of Penmetsa et al., in which the exfoliative cytology was also used to detect the titanium particle in a group which has mild gingivitis and another group which has moderate-to-severe condition, also has the similar result. Sixty percent of the specimens in the moderate-to-severe group had titanium particles in peri-implant cytology.

In Wilson et al. study, 34 among a total of 36 human peri-implantitis biopsies were analyzed. The SEM images revealed the predominant titanium particle surrounded by inflammatory cells. The study mentions three possibilities that can cause the presence of titanium particle in surrounding tissue.