Differentiation of HA coatings.

Controversy has recently arisen regarding hydroxylapatite (HA) coatings and HA-coated implants. The frequent absence of information about relevant scientific parameters in critical articles and presentations makes it difficult for clinicians to accurately assess the validity of these reports and/or the quality of the products being reported. In order to make informed decisions regarding HA-coated products, clinicians need to familiarize themselves with the critical variables of HA crystallinity, purity, density, bond strength, and dissolution rate. Clinical and histological studies indicate that when high standards are observed for these five parameters, HA coatings and HA-coated products provide a reliable component of the clinical armamentarium.