Inhibitory effect of magnesium and zinc on crystallization kinetics of hydroxyapatite (0001) face

The effect of magnesium and zinc on the growth kinetics of a hydroxyapatite (0001) face in pseudophysiological solutions was investigated. The growth rates of the (0001) face were measured under various concentrations of magn esium or zinc using Moire phase shift interferometry coupled with surface o bservation by atomic force microscopy. The (0001) face grew not in a spiral growth mode but in a multiple two-dimensional nucleation growth mode. It w as shown that the lateral growth of two-dimensional islands on the (0001) f ace was inhibited by the addition of magnesium or zinc, following an inhibi tion of the normal growth rate of the face. Although both cations inhibited growth, zinc was found to reduce the growth rate about 1000 times more eff ectively than magnesium.