Objective To study the influence of different kinds of disinfection methods on antibacterial activity of TiO2 nanotubes. Methods TiO2 nanotubes were fabricated with 0.5%wt HF on pure titanium to acid-etching combined with an? odization as experimental group. The pure Ti was control group. They were disinfected by three kinds of disinfection meth?ods, which were alcohol immersion, autoclaving and UV irradiation. The bacterial adhesion ability was evaluated by observ?ing the morphology of samples, measuring the roughness and contracting angle. The film contact method was used to evaluate the antibacterial activity of samples with Staphylococcus aureus (Sa) after different infection treatment. The bacterial morphol?ogy was observed by field emission scanning electron microscope (FE-SEM). Results The treatment group has higher sur?face roughness. The bacterial adhesion ability of experimental group was stronger compared with that of control group. The contracting angle of samples exposed to UV irradiation was smaller than that of alcohol immersion and autoclaving treatment group. The viable count and FE-SEM showed that there were more bacteria and more complete morphology on the sample surface after alcohol immersion. The viable count was less and bacterial morphology suffered some damage on the sample sur?face after high pressure steam sterilization. The least viable count and the most complete destruction of bacterial morphology were found after ultraviolet (UV) germicidal irradiation. Conclusion UV irradiation shows the best antibacterial activity, the second is autoclaving and the worst is alcohol immersion.

Objective: To investigate the effects of two nanotopographies of ultraviolet (UV)-treated titanium surface on macrophage biological behaviour and inflammatory cytokines secretion, and to provide basis for clinical application of UV-treatment in dental implant modification. Methods: Titanium disks were allocated into two groups. Samples in one group were acid-etched in hydrofluoric acid (Acid Ti group), and those in the other group were acid-etched and anodized (Anodization group) to form two nanotopographies respectively. The surface morphology was evaluated by field-emission scanning electron microscopy (FE-SEM). The samples were stored in the dark for 8 weeks. Thirteen samples from each group were exposed to UV-irradiation for 48 h (Acid Ti+UV group and Anodization+UV group), UV-untreated samples from Acid Ti and Anodization groups served as control. Hydrophilicity of samples was measured using contact angle measuring device. After 4, 24 and 72 h of incubation, macrophage cell adhesion and proliferation were conducted using cell counting kit-8. Cytokine/chemokine secretions [tumor necrosis factor-α (TNF-α), monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α)] were measured from cell culture supernatants at 24 and 72 h using magnetic luminex assay. Cell morphology was examined using FE-SEM after 2 h of incubation. Results: Micropitted/nanopillar and micropitted/nanotubular topographies were observed in Acid Ti group and Anodization group respectively. Contact angles in Acid Ti+UV and Anodization+UV groups (20.2°±2.8° and 0.0°±0.0°) were significantly smaller than those in the Acid Ti and Anodization groups (P<0.05). Cell adhesion and proliferation in all groups at 4 and 24 h showed no difference (P>0.05). Cell proliferation in Acid Ti+UV and Anodization+UV groups at 72 h were (0.92±0.13) and (1.10±0.08) respectively, which were significantly higher than those in Acid Ti and Anodization groups. TNF-α concentration in Acid Ti+UV and Anodization+UV groups at 72 h were (1.03±0.11) and (0.87±0.10) ng/L, MCP-1 were (301.7±50.3) and (240.8±18.7) ng/L, MIP-1α were (224.9±30.6) and (233.9±14.9) ng/L respectively, which were significantly lower than those in Acid Ti and Anodization groups (P<0.05). Conclusions UV treatment can increase hydrophilicity of two titanium surface topographies, especially of Anodization+UV group. UV-treated titanium surfaces can promote macrophage proliferation and reduce the inflammatory response in vitro.