Comparative Study for the Dissolution of Bone Ash-Derived and Artificial Hydroxyapatite

Abstract

Hydroxyapatite (HA) ceramics were prepared from the bone ash which is mostly used as animal feeds or raw materials. Dissolving behaviors of the HA in buffered water were investigated and compared with commercial HA for further use as biomaterials. HA ceramics were prepared by soaking the bone ash in 0.1 M of NaOH solution at 80°C for 4 h. The ash was calcined at 800°C for 1 h to completely remove organics, and then sintered at 1200°C for 1 h under moisture protection. The bone ash derived-HA consists of mostly HA and small amounts of α-tricalcium phosphate, calcium oxide phosphate, magnesium oxide and calcium oxide. After polishing the HA ceramics, they were immersed in buffered water at 37°C for 3 and 7 days. We previously found that grain boundaries of synthetic HA were intensively dissolved in buffered water. On the other hand, the bone ash derived-HA shows high stability in liquid environment with immersion time compared with commercial HA.