Ceramics-Silikáty 51 (3) 136-141 (2007)

CRYSTALLIZATION MECHANISM AND BIOACTIVITY OF LITHIUM DISILICATE GLASSES IN RELATION TO CaO, P₂O₅, CaF₂ ADDITION

E. Kuzielová , M. Palou , J. Kozánková

The present investigation reports the results of P₂O₅, CaO and CaF₂ (in stechiometric ratio corresponding to fluoroapatite) effect upon the controlled crystallization of grain-sized particles of lithium disilicate (LS₂) glass and upon the bioactivity of given glasses, that have been investigated by means of DTA and by in vitro testing after 4 weeks, respectively. The crystallization of pure lithium disilicate glass as well as that of glass containing the above components proceeds by surface and internal mechanism as function of particle size. The onset of internal crystallization, which substitutes the surface one is found at about 0.3 mm for pure lithium disilicate glass, while this change occurred at size of 0.9 mm approximately in glass containing CaO, P₂O₅ and CaF₂. The addition of different amount of "apparent fluoroapatite" enhances the bioactivity of bioglasses as confirmed by SEM and EPMA.

Keywords: Lithium disilicate, Fluoroapatite, Crystallization mechanisms, Bioactivity