FLUORIDATED CARBONATOAPATITE IN THE INTERMEDIATE LAYER BETWEEN GLASS-IONOMER AND DENTIN

The intermediate layer between a glass ionomer restoration and dentin was examined morphologically by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). SEM showed strong bonding between the dentin and glass ionomer and formation of an intermediate layer between them. FTIR spectra of successive scrapings through the ionomer/dentin interface zone showed that the intermediate layer is composed primarily of mineral fluoridated carbonatoapatite. The presence of this sparingly soluble mineral at the interface between the tooth and the restoration may provide high resistance to secondary caries and may, thus, be of great clinical importance.