Bio-functionalization of titanium surfaces for dental implants

Since dental implants are used in contact with many different tissues, it is necessary to have optimum surface compatibility with the host bone tissues and soft tissues. Furthermore, dental implant surfaces exposed to the oral cavity must remain plaque-free. Such materials can be created under well-controlled conditions by modifying the surfaces of metals that contact those tissues. "Tissue-compatible implants," which are compatible with all host tissues, must integrate with bone tissue, easily form hemidesmosomes, and prevent bacterial adhesion. This research was aimed at developing such tissue-compatible implants by modifying titanium surfaces using a dry process for closely adhering to the titanium substrate and ensuring good wear resistance. The process includes ion beam dynamic mixing (thin calcium phosphates), ion implantation, titania spraying, ion plating and ion beam mixing. At the bone tissue/implant interface, a thin calcium phosphate coating and rapid heating with infrared radiation was effective in controlling the dissolution without cracking the coating. This thin calcium phosphate coating may directly promote osteogenisis, but also enable immobilization of functional proteins or drugs such as bisphosphonate for dug delivery system. At the oral fluid/implant interface, an alumina coating and F+-implantation were responsible for inhibiting the adhesion of microbial plaque. In conclusion, dry-process surface modification is useful in controlling the physicochemical nature of surfaces, including the surface energy and the surface electrical charge, and in developing tissue-compatible implants.