Fluoride releasing photothermal responsive TiO₂ matrices for antibiosis, biosealing and bone regeneration

Peri-implantitis induced by infection leads to gingival recession, alveolar resorption and eventual dental implant failure. So, antibiosis and biosealing of abutments as well as osseointegration of roots need to be projected seriously during the whole service lifespan of dental implants. In this work, a multipurpose photothermal therapy strategy based on Si/P/F doped TiO₂ matrix is proposed to address the above issues. This TiO₂ matrix not only has outstanding photothermal response, but also triggers the release of F ions under near-infrared (NIR) light irradiation. Local hyperthermia assisted with the released F ions reduces adenosine triphosphate (ATP) synthesis of staphylococcus aureus (S. aureus), increases bacterial membrane permeability, and induces abundant of reactive oxygen species, resulting in the oxidation of cellular components and eventual death of bacteria. Furthermore, the synergic action of mild photothermal stimulation and Si/P/F ions of TiO₂ matrix up-regulates gingival epithelial cells behavior (e.g., hemidesmosome formation) and osteoblasts response in vitro. In an infected model, this TiO₂ matrix obviously eliminates bacteria, reduces inflammatory response, improves epithelial sealing and osseointegration, and reduces alveolar resorption by regulating NIR irradiation.