Recent studies showed that the particle size of fillers, using for the reinforcement of dental resin composites, should be as small as possible to provide the maximum surface area for bonding to resin monomer, and should be kept well dispersed so as to be functionalized by a silane. In the present study, porous alumina monoliths with high specific surface area, measured by the Brunauer-Emmett-Teller (B.E.T.) method, were obtained using a novel preparation method. Structure and surface reactivity have been investigated as functions of temperature and chemical treatments. The impregnation of the as-prepared material by Triméthyletoxysilane (TMES) stabilized alumina with high specific surface area at higher temperature. A FTIR study has described the effect of TMES treatment and temperature on the structure of the material. The use of allyldimethoxysilane (ADMS) as a probe molecule for measuring the surface reactivity, has allowed us to show that the treatment of samples with TMES and their reheating at 1300°C results in adsorption sites which give stronger chemical bonds. This preliminary study has, therefore, allowed us to optimize the structural and surface treatment of experimental fillers before their use in the reinforcement of resin composites or resin-modified glass-ionomer cements.