Abstract: The present invention provides a functionally graded bioactive glass/ceramic composite structure or bioactive glass/ceramic/bioactive glass sandwich structure for use in such applications as damage resistant, ceramic dental implants, immediate tooth replacement, endodontic posts, orthopedic prostheses, orthopedic stems, bone substitutes, bone screws, plates, and anchors, nonunion fractures repair, alveolar ridge augmentation, missing small bone parts (e.g. fingers, toes, etc), maxilla facial reconstruction, spinal fusion, and scaffolds for bone regeneration, comprising a residual bioactive glass or glass-ceramic layer at all accessible surfaces, followed by an underlying graded glass-ceramic layer, and then an dense interior ceramic. The residual bioactive glass or glass-ceramic layer can be further transformed to a carbonate apatite (CHA) layer by immersing in calcifying solution or simulated body fluid (SBF) with electrolyte composition similar to that of serum.