Three-dimensional defects in hydroxyapatite of biological interest.

Hydroxyapatite (HA) ceramics are widely used as bone substitutes in the repair of bony defects. These ceramics sometimes differ in their sintering temperatures. High resolution transmission electron microscopy was used to characterize HA ceramics sintered at different temperatures. A new type of defect was observed for the first time for ceramics prepared at 900 degrees C but not on those prepared at 1250 degrees C. This may cause a difference in their in vitro dissolution and in vivo performance.