Fabrication of bioactive glass-ceramics by selective laser sintering

The feasibility of processing glass-ceramics using the layer manufacturing technique, selective laser sintering (SLS), to produce parts with suitable biological and mechanical properties for use in bone replacement applications, has been investigated. Glass-ceramics derived from glasses based on several different systems have been considered. Initial experiments using an apatite-mullite glass-ceramic (4.5SiO(2)center dot 3Al(2)0(3)center dot 1.6P(2)O(5)center dot 3CaO center dot 2CaF(2)) demonstrated the ability to process glass-ceramic materials using this technique, creating parts with a strength similar to that of cancellous bone, and a porous structure that was shown in vivo to be suitable for the ingrowth of bone. Concerns over the inability of the apatite-mullite material to form an apatite layer on its surface when soaked in a simulated body fluid (SBF) has led to the development of Al2O3-free glasses based on the systems (50-x)CaO center dot 45SiO(2)center dot 5P(2)O(5)center dot xCaF(2) and (48-x)CaO center dot 45SiO(2)center dot 5P(2)O(5)center dot 2CaF(2)center dot xNa(2)O. These materials have demonstrated good in vitro bioactivity, and therefore have good potential as candidates for processing by an indirect SLS method for the production of custom-made bone implants.