Engineering of Carbonate Apatite Bone Substitute Based on Composition-Transformation of Gypsum and Calcium Hydroxide

Even though a lot of research has been carried out concerning the preparation of carbonate apatite (CHA), they were related to CHA in the form of powder. In the present study, macroporous CHA bone substitutes were prepared through composition-transformation of gypsum and Ca-hydroxide. Here, we investigated the effect of added Ca-hydroxide to gypsum, carbonation periods, and hydrothermal temperatures for phosphatization to understand the basic principle of composition-transformation of gypsum added Ca-hydroxide to fabricate CHA bone substitutes. The specimens were characterized in terms of chemical and physical properties, such as extent of transformation of macroporous gypsum added Ca-hydroxide into CHA body, type and content of carbonate, and crystal morphology. It was observed that the transformation was faster with higher hydrothermal temperature. However, higher hydrothermal temperature caused de-carbonation phenomena which resulted in the lack of carbonate ions of the product. Moreover, the higher the percentage of Ca-hydroxide added to gypsum, caused the complete transformation of gypsum into CHA to be slower. These findings have been applied to the standard fabrication procedure of carbonate apatite, which in turn will allow scaling up process, and will be provided for biomedical purposes for the Indonesian community.