Calcium phosphate coatings: understanding the chemistry and biology and their effective use.

Unlike titanium dental implants, hydroxyapatite (HA)-coated implants have the ability to form a chemical bond with bone. Clinicians must understand the chemical, physical, and mechanical properties of HA, as well as the differences between superior and inferior HA coatings. In fact, because not all HA coatings are the same, there are guidelines to analyze the coatings according to chemical composition, density, crystallinity, levels of impurities, surface roughness, and tensile and shear strengths. HA coatings have shown definite advantages over uncoated implants, but improvements are still needed in areas such as attachment, porosity, and crystallinity.