Time course of surface characteristics of alkali- and heat-treated titanium dental implants during vacuum storage

Current efforts to shorten the healing times of lifelong dental implants and prevent their fouling by organic impurities have focused on using surface-modification treatments and alternative packaging, respectively. In this study, we investigated the time course of the surface characteristics, including the wettability, a protein-adsorption and apatite-formation abilities, of alkali-and heat-treated (AH-treated) Ti samples during storage in vacuum over a period of 52 weeks. The AH treatment resulted in the formation of a nano-meterscale needle-like rougher surface of the Ti samples. Although the water contact angle of the AH-treated Ti sample increased slightly, it remained as low as approximately 108 even after storage in vacuum for 52 weeks. There was no significant difference in the protein-adsorption and apatite-formation abilities of the AH-treated Ti sample before and after storage. Further, the AH-treated Ti sample exhibited greater proteinadsorption and apatite-formation abilities compared with the untreated one; regardless of the samples stored in vacuum or not. Apatite formed only on the AH-treated Ti surface. Therefore, subjecting Ti dental implants to the AH treatment and storing them in vacuum should help prevent their surfaces from getting contaminated. Further, it is expected that AH-treated Ti dental implants controllably aged during a shelf storage will exhibit high stability and bone-bonding bioactivity. (C) 2016 Wiley Periodicals, Inc.