The first studies on the cement forming ability of the glasses employed in the formulation of useful glass-ionomer cements attributed a crucial role to the Al2O3/SiO2 ratio, which was required to be higher than 1/2 by mass for cement formation. More recently, the use of the concepts such as network connectivity or crosslink density to formulate glass compositions with a good cement-forming ability has been proposed in the literature. In the present work, the effect of network connectivity on the cement-formation ability of high purity, homogeneous sol-gel glasses of different compositions in the SiO2-Al2O3-CaO-CaF2 system was qualitatively evaluated by FTIR spectroscopy. The cement-forming ability of the calcined sol-gel glasses was assessed at different powder/liquid ratios by determining their setting behaviour according to the procedure described in the ISO 9917 - Dental water-based cements. The network connectivities of the calcined sol-gel glasses were qualitatively evaluated by Fourier transform infrared (FTIR) spectroscopy. The analysis of the FTIR spectra provided useful qualitative information on the network connectivity of the sol-gel glasses, which proved to be more efficient than the Al2O3/SiO2 ratio as a way of evaluating and predicting the reactivity, and hence, the cement forming ability of these glasses.192-195749752McLean, J.W., Nicholson, J.W., Wilson, A.D., (1994) Quintessence International, 25, p. 577Wilson, A.D., McLean, J.W., (1988) Glass -Ionomer Cement, p. 2748. , Illinois Quintessence Publishing CoHill, R.G., (1996) J. Mater. Sci Letters, 15, p. 1122Darling, M., Hill, R., (1994) Journal of Dentistry, 5, p. 299Zolotar, M.S., Bavaresco, V.P., Zavaglia, C.A.C., (1999) J. Non-Cryst. Sol., 247, p. 50(1991) Dental Water-Based Cements, p. 138. , International Standard Organization,Genévre.ISO-9917Villegas, M.A., Navarro, J.M.F., (1988) J. Mater. Sci, 23, p. 2464Bansal, N.P., (1992) J. Mater. Sci, 27, p. 292
