Table 2.
Different ionic elements substituted into the HA structure for improving its functions.
| Substitution Ion | Function | |
|---|---|---|
| Cation | Na+ | Excellent osteoconductivity, improvement of cell proliferation |
| K+ | Improvement of thermal stability | |
| Mg2+ | Enhancement of crystallization, crystal growth, thermal stability, influence on the dissolution | |
| Sr2+ | Inhibition of bone resorption, enhancement of bone formation | |
| Mn2+ | Cell adhesion activation | |
| Zn2+ | Enhancement of bone formation | |
| Anion | SiO44− | Enhancement of bioactivity, improvement of dissolution speed |
| CO32− | Higher specific surface area, lower crystallite size, excellent osteoconductive properties, higher solubility | |
| F− | Higher stability, lower solubility, promotion of remineralization | |
| Cl− | Excellent osteoconductive properties, higher solubility | |