In vivo hydrating calcium aluminate coatings for anchoring of metal implants in bone

Early fixation of metal implants in bone tissue is beneficial both in allowing for early loading (of particular interest for dental implants) and reduces the risk for long-term loosening due to reduced micro-motions. This paper investigates the prospects of achieving early anchoring of the metal implant to bone tissue by exploring coatings systems based on chemically bonded ceramics, particularly coatings of calcium aluminate. Coatings of chemically bonded ceramics potentially provide systems for fast anchoring of implants to bone tissue characterized by a high strength bond between the coating to the implant surface, resulting from the build-up of a chemical bond as the coating cures; inter-connection of sub-layers of the coatings by their co-hydration; and for selected applications also anchoring of the coating to a ceramic paste by co-hydration. The dissolution-precipitation mechanisms of chemically bonded ceramics also contribute to the anchoring of the ceramic to the biological tissue. This paper presents results from an investigation of early anchoring of dental implants coated with calcium aluminate films of different characteristics in a rabbit model. Evidence is presented of the anchoring mechanisms of the coating realized by precipitation of hydrates.