Comparison of hydroxyapatite powders derived from different resources

There is a great demand of Hydroxyapatite (HA) material in Orthopaedics and Dental applications due to its similarity to human bone. However, the lack of availability and due to high import cost of this material in Malaysia, research in producing synthetic HA locally is therefore timely. The use of local resources as the raw materials for the production of HA is also desirable in reducing the overall cost of HA. In this study, two HA materials were synthesised from different starting precursors, i.e. commercial pure Ca(OH)2 (HAS) and Ca(OH)2 directly from a local natural limestone deposit (HAL). Whereas a commercially available HA "Captal 60" (HAC) was used as reference. The synthesised powders obtained were fired at 1000 degrees C and at 1250 degrees C. Characterisation evaluations on bulk properties were carried out using XRD, SEM-EDX, ICP and FTIR. The results indicate that both HAS and HAL are comparable to HAC even at 1000 degrees C. Thus, the local natural limestone can be used to form HA. However, the overall appearance of these materials are quite different (HAC - blue, HAS - greenish and HAL - light green). The reasons for this and the subsequent mechanical and bioactive effects of these materials are currently being investigated.