Surface treatments on titanium implants via nanostructured ceria for antibacterial and anti-inflammatory capabilities.

Peri-implantitis is the most common risk factor for dental implant failure. Nanostructured ceria (nano-CeO2) has anti-inflammatory and antibacterial functions, and different shapes of ceria enclosed by specific crystal planes could be an effective approach to enhance intrinsic catalysis. In the present study, the authors developed a novel implant surface-modification strategy by coating different shapes of nano-CeO2 onto titanium (Ti) surfaces to enhance their antibacterial and anti-inflammatory properties. The objectives of the study were to: (1) develop novel Ti surfaces modified with different shapes of nano-CeO2 (nanorod, nanocube and nano-octahedron) for peri-implantitis prevention; (2) investigate and compare the inhibition efficacy of different shapes of CeO2-modified surfaces against biofilms of peri-implantitis-related pathogens; and (3) evaluate the different CeO2-modified surfaces on cell inflammatory response in vitro and in vivo. The results showed that nanorod CeO2-modified Ti had more bacteria attachment of Streptococcus sanguinis in the early stage, compared with other CeO2-modified Ti (p < 0.05). They all exhibited similarly substantial CFU reductions against peri-implantitis-related biofilms (p > 0.1). Nanocube and nano-octahedron CeO2-modified Ti exerted much better anti-inflammatory effects and ROS-scavenging ability than nanorod CeO2in vitro (p < 0.05). In vivo, the mean mRNA expression of TNF-α, IL-6 and IL-1β in the tissues around Ti was decreased by the three shapes of nano-CeO2; nano-octahedron CeO2 showed the strongest anti-inflammatory effect among all groups (p < 0.05). In conclusion, all three types of CeO2-modified Ti exerted equally strong antibacterial properties; nano-octahedron CeO2-modified Ti had the best anti-inflammatory effect. Therefore, CeO2-modified Ti surfaces are highly promising for enhancing antimicrobial functions for dental implants. Novel nano-octahedron CeO2 coating on Ti had great therapeutic potential for alleviating and eliminating peri-implantitis. STATEMENT OF SIGNIFICANCE: Peri-implantitis is the most common risk factor for dental implant failure. Nanostructured ceria (nano-CeO2) has anti-inflammatory and antibacterial functions, and different shapes of ceria enclosed by specific crystal planes could be an effective approach to enhance intrinsic catalysis. In the present study, we developed a novel implant surface-modification strategy by coating different shapes of nano-CeO2 onto titanium surfaces to enhance their antibacterial and anti-inflammatory properties for dental implants. In addition, we found that the nano-octahedron CeO2 coating on titanium would have great therapeutic potential for alleviating and eliminating peri-implantitis.