Photocatalytic cleaning effect of TiO2 nanowires increase the osteoconductivity of the titanium surface

Establishing early osseointegration of titanium implants is the premise and foundation for the success of dental implants and titanium surface cleanliness is a key factor for improving the early response of osteoblasts. The photocatalytic cleaning effect of TiO2 nanowires (NWs) on the titanium surface is more attractive to cells than UV light treatment alone. This study determined whether the photocatalytic cleaning effect of TiO2 NWs enhanced new bone deposition in vitro and in vivo and the establishment of early osseointegration on titanium surfaces. TiO2 NWs were fabricated by alkaline hydrothermal synthesis as previous reported. Sandblasted with large grit and acid-etched titanium plates and implants were treated with photocatalytic cleaning of TiO2 NWs. Protein adsorption, cell mineralization, osteoblast-attracting ability, and cytoskeletal extension assays were performed using an in vitro model. Four adult male beagle dogs were used to estimate new bone deposition around titanium implants in an in vivo model. The increased affinity of the titanium surface cleaned by the photocatalysis of TiO2 NWs promoted protein adsorption, as well as the migration of cells to the surface and cellular extension. In vivo histomorphometry in a beagle dog model revealed that new bone formation around the titanium implants cleaned by photocatalysis with TiO2 NWs was significantly improved. The measurements of bone-implant contact (BIC) and bone area (BA) were approximately 1.5 times and 1.2 times higher than those of the titanium surface control group at 2 and 4 weeks, respectively, and also had a significant advantage on bone regeneration over the UV irradiation treatment group alone. Titanium surfaces cleaned by the photocatalytic effect of TiO2 NWs promoted new bone formation, which had a significant advantage over UV irradiation treatment alone. Photocatalytic decontamination of titanium surfaces as a novel surface treatment is expected to promote the establishment of early osseointegration and long-term clinical stability of titanium implants.