Osseoconductive hydroxyapatite coatings

The advantages of an osseoconductive hydroxyapatite coating include (see also Chapter 3.7)... 

Current trends in coating biomedical implants with osseoconductive nanostruc-tured hydroxyapatite coatings lean towards thin (<50 pm) homogeneous layers that are able to maintain the roughened microstructure of the implant substrate conducive to cell attachment and to minimise residual stresses and thus reduce the risk of coating delamination. 

Cook, 1991). This finding was indeed one of the first strong confirmations of the osseoconductive properties of a hydroxyapatite coating and has triggered much related work ever since. 

Another way to improve the mechanical properties of osseoconductive coatings is to add reinforcing ceramic or polymer materials. In the context of this treatise, only ceramic additive such as titania or zirconia will be briefly discussed. Hence, hydroxyapatite/polymer composite coatings will be excluded from discussion. 

It might be argued that the results by Jager et al. (2006) discussed and interpreted earlier pertain only to nanocrystalline hydroxyapatite synthesised from an aqueous solution. However, they are clearly relevant to calcium phosphate biomimetically precipitated from SBFs used to validate the degree of osseoconductivity of bioceramic coatings. 

---