This project is developing a new generation of calcium phosphate coatings for dental implants, in which film crystallinity is optimized for enhanced bioactivity and osseointegration. Phase I examined the hypothesis that optimal crystallinity leads to more rapid and stronger device fixation. Film crystallinities ranging from 30-90% were produced by a novel, low temperature deposition method and evaluated in a small animal model (rat). It was found that the ideal range was between 50-70% crystalline. These coatings provided bone-device integration compared to conventional plasma spray coatings. The purpose of the Phase II program is to further evaluate and demonstrate the advantage of calcium phosphate coatings with optimized crystallinity, as defined in Phase I. Both early and long-term bone response will be assessed in a large animal (canine) model, both prior to and after prosthesis loading. The desire to introduce this innovative technology to the field of dental implantology is based on two primary advantages of the process over existing technology used to apply HA coatings to implants. First, the chemical composition and crystallinity of the applied coating can be precisely controlled over a wide range of values, without the need for post deposition annealing. Second, the HA coatings can be deposited at low temperature as thin films from 1 to 5 mu/m thick, much thinner than coatings applied using plasma spray technology. Thinner coatings can provide a higher interfacial strength and better resistance than thicker plasma spray coatings.
