Structural modifications and biological compatibility of doped bio-active glasses

The Raman laser and infrared spectra of doped bio-active glasses of the 45S5 type are presented and discussed. The spectroscopic results show that the doping agents cause the destruction of the basic glass structure and the consequent formation of SiO4(4-) units in the glass network. When the doped glasses have been immersed in a physiological solution (199 medium), a film of calcite forms on the glass surface and this modification is related to the type of doping agent used, decisive for close linking between metal supports and the glass. The presence of doping agents does not prevent the normal growth of the bone onto the surface of doped bioactive glasses. Histological tests show that tissue response to very fine powders of doped glasses increases up to 15 days more or less according to the structural modifications revealed by spectroscopic measurements.