Growth and Fusion of Apatite Crystals in the Remineralized Enamel

Abstract

The present study was carried out to observe the process of growth and fusion of apatite crystals in human enamel remineralized in vitro in a solution containing Ca, 1 mM; P, 0.6 mM; and F, 0.05 mM. The growth of newly formed crystals and the regrowth of pre-existing enamel crystals occurred extensively in remineralized enamel. With advancing growth, the crystals came into contact and fused with each other, forming large crystals with hexagonal outlines. Various kinds of crystalline defects, including edge dislocation, low-angle grain boundary, and lattice shifting, were frequently detected between the fusing crystals. X-ray diffraction and electron-probe studies led to the assumption that the regular-hexagonal crystals were fluoroapatite.