Effect of magnesium to the properties of biphasic calcium phosphate (bcp) for bone regeneration
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Date
2019-07
Authors
Lee Moi Ging
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Abstract
Currently, bone related diseases lead to a clinical need for bone reconstruction and repair. Calcium phosphate included hydroxyapatite (HA) and beta tricalcium phosphate (β-TCP) that are been used as bone graft. However, pure HA and pure β-TCP are not suitable for biomedical application due to low biodegradation rate and mechanical properties, respectively. Therefore, biphasic calcium phosphate (BCP) and magnesium biphasic calcium phosphate (Mg-BCP) is combination both HA and β-TCP in order to enhance the properties by manipulated the ratio of HA and β-TCP. This study was conducted to investigate the effect of magnesium and sintering temperature to the properties of BCP and Mg-BCP. The as-synthesized powder was then press into pellets form followed by sintered at different temperature (600°C, 900°C, 1000°C, 1100°C) then immersed into Hank balance Salt Solution (HBSS) for 7 days and 28 days. There are several characterization techniques was used such XRD, FESEM, EDX, FTIR, TG-DSC, density/porosity, shrinkage and compressive strength testing. By increasing sintering temperature, the compressive strength of sintered pellets had been improved. The highest compressive strength of BCP and Mg-BCP is 8.47 MPa and 9.85MPa, respectively. This is due to densification with aid of diffusion mechanism which reduced porosity that act as stress concentration site. Furthermore, the effect of Mg2+ on phase formation found that it suppress HA phase and favors β-TCP phase. Therefore, the Mg-BCP pellets were dominant by β-TCP phase. Additionally, the Mg2+ dopant in BCP was enhanced densification and imposed drag on grain boundary movement which leads to small grain size and indirectly increases compressive strength. In term of bioactivity properties, the Mg-BCP was soaked in HBSS for 7 days and 28 days. The results show more apatite formation on surface of Mg-BCP than BCP. Due to the addition of Mg2+, the dissolution – reprecipitation properties of BCP had been improved due to lower crystallinity. Besides, the presence of alkaline ion (Mg2+) has help to neutral acidic of HBSS due to the release of acidic HPO4- . Briefly, the Mg-BCP shows better mechanical and biological properties than BCP which more potential to be utilized as biomaterial.