Advances in Bioceramics and Porous Ceramics V Vol. 33 No. 6 (2012) pp.7-10 John Wiley & Sons, Inc., Hoboken, NJ, USA.
DOI: 10.1002/9781118217504.ch2
CARBONATE APATITE FORMATION DURING THE SETTING REACTION OF APATITE CEMENT
Arief Cahyanto, Kanji Tsuru, and Kunio Ishikawa
Department of Biomaterials, Faculty of Dental Science, Kyushu University, Fukuoka, JAPAN
ABSTRACT
Replacement of apatite cement (AC) to bone is still controversial issue. To understand factor that could affect the replacement of AC to bone, AC consisting of an equimolar mixture of tetracalcium phosphate (TTCP; Ca4(PO4)2O) and dicalcium
phosphate anhydrous (DCPA; CaHPO4) was allowed to set at 37°C and 100% relative
humidity under 5% CO2 or N2. Carbonate apatite (CO3Ap) was formed when AC was
allowed to set under 5% CO2. The amount of CO3 decreased gradually as the depth
from the surface increased. The CO3Ap was the B-type CO3Ap in which CO32- was
replaced with PO43- and the CO3Ap found in bone. Larger amount of TTCP remain
unreacted when the AC was allowed to set under N2 whereas smaller amount of
TTCP remain unreacted when the AC was allowed to set under CO2. This may be
caused by the larger Ca/P molar ratio of CO3Ap. Formation of CO3Ap and/or small
unreacted TTCP are thought to be key factors for the replacement of AC to bone.
