Two rectangular bars of glass-ceramic A-W, its parent glass G, Bioglass Bg or hydroxyapatite ceramic HAp were respectively bound and soaked in an acellular simulated body fluid for various periods up to 6 months. Tight chemical bond was formed between the two bars after a certain period of time for all these bioactive materials. The ability of forming such bond increased in the order HAp<G=A-W<Bg. The bond was achieved by an apatite phase newly formed at the interfaces of the specimens in the simulated body fluid. In the present arrangement of the specimens, bonding took place in the peripheries within the interface, indicating that wider area for bonding and accordingly stronger bonding can be expected if the arrangement is designed so that the fluid might circulate into the central part of the interface. The present results indicate a possibility that when artificial bone made of those bioactive materials is accidentally broken in a body, the separate pieces can be recombined like the natural bone.
