Biological evaluation of nano hydroxyapatite zirconia (HA-ZrO2) composites for load bearing applications.

The biological response of strontium (Sr) doped hydroxyapatite (HA) and hydroxyapatitezirconia (HA-ZrO2) composites produced by employing sol-gel technology, minimal ZrO2 loadings and novel microwave sintering regimes thereby retarding decomposition, is reported. In vitro evaluations indicate that all materials induce a favourable response from rat osteosarcoma cells (ROS). In vivo evaluations show osteoconductivity and biocompatibility for both the Sr-HA and HA-ZrO2. The materials did not cause any inflammatory response in bone. The Sr-HA displays better biocompatibility which may be a due to the incorporation of Sr and the formation of a surface apatite layer.