Abstract: A method of making a sol-gel monolith, comprising the steps of:(a) hydrolyzing and polycondensing one or more oxide precursors to form a sol comprising a plurality of oxide particles suspended in a liquid;(b) casting said sol into a mold;(c) gelling said sol by cross-linking said oxide particles to form a gel;(d) aging said gel to form an aged gel;(e) subjecting said aged gel to a drying treatment comprising the steps of:(i) heating said aged gel in a high humidity environment; and then(ii) heating said aged gel in a low humidity environmentto remove liquid from the pores of the aged gel to form a dried, aged gel; and(f) densifying said dried, aged gel to form a sol-gel monolith.

Abstract: Sol-gel processing techniques are used to produce alkali-free bioactive glass compositions based on SiO.sub.2, CaO and P.sub.2 O.sub.5. By varying the SiO.sub.2 content, a range of hydroxyapatite production rates can be obtained; conversely, varying the time of exposure to actual or simulated in vivo solutions permits use of a range of allowable proportions of SiO.sub.2. The sol-gel derived compositions can be chosen to achieve target values for thermal expansion coefficient, elastic modulus and volume electrical resistivity.