Apatite-forming ability of glass-ceramics containing whitlockite and diopside in a simulated body fluid

Tricalcium phosphate (SCaO·P₂O₅, TCP) is known as a biodegradable material and already used clinically as important bone-repairing materials. However, the control of its bone-bonding ability, i.e. bioactivity, and biodegradability is not easy. On the other hand, diopside (CaO·MgO·2SiO₂) ceramic shows a potential of direct contact with bone and high mechanical strength, but low biodegradability. We expected that a glass-ceramic containing TCP and diopside show high bioactivity and high mechanical strength, as well as biodegradability. Glasses with composition x(3CaO·P₂O₅)·(100-x) (CaO·MgO·2SiO₂) (x = 0, 38, 50, 60 mass%) were prepared. They were pulverized and the compacts of the resultant powders were heated to obtain the glass-ceramics. Only diopside was precipitated at x = 0 in the glass composition, whitlockite (β-TCP) and diopside were at x = 38, 50 and 60, when the compacts were sintered at 1200°C. The prepared glass-ceramics formed apatite on their surfaces in a simulated body fluid (SBF). This indicates that these glass-ceramics have a potential to show bioactivity.