Dense, porous, resorbable and nonresorbable are all too familiar terms associated with hydroxylapatite (HA) bone grafting materials. While each of the above have their clinical applicability in osseous oral rehabilitation, the HA powder characteristics that ensure optimal plasma spray coatings to implants are distinctly different.
The powder's calcium phosphate phases, the density of the powder, the particle size of the powder and the particle shape and subsequent flow characteristics all can impact upon the quality of the final HA coating. These physical properties coupled to controlling the melt of the powder surface are shown to be related to the quality of HA coatings on implants with respect to crystallinity and bonding strengths. While multiple parameters are important in plasma spraying, control of the powder is the first step toward high-quality coatings.