“…Previous studies found that suspected pathogenic bacteria such as Porphyromonas gingivalis and Actinobacillus could colonized on the surface of Ti. Their metabolites reduced the local pH value in a short time, destroyed the oxide film on the surface of Ti, and caused corrosion and release of Ti ions (Xu, Yu, Chen, Zhang, & Qiu, 2020;Zhang et al, 2013). Besides microbial corrosion, many corrosion types exist around the Ti implant, such as stress corrosion, osteoclast corrosion, oxidative corrosion, pitting corrosion, fretting corrosion, and so on, which affect and promote each other, eventually leading to the release and aggregation of Ti ions (Cadosch et al, 2010;Golvano, Garcia, Conde, Tato, & Aginagalde, 2015;Zhu et al, 2019).…”