Bone replacement for use in periodontology, orthopaedics and traumatology
Bone repair is an attractive and natural target for tissue engineering, since bone regeneration is required for the therapy of numerous serious clinical indications. Large segmental defects of diaphyseal bone, connected with acute injury as well as other massive defects, congenital malformations, benign and malignant tumours or osseous infections. In addition, there is a substantial need for bone regeneration therapy in spinal arthrodesis, in fixation of prosthetic implants and restoration of maxillofacial structures. Currently, autogenous bone is most frequently used by surgeons and is the graft treatment of choice to augment and restore deficient osseous structures. Unfortunately, there is insufficient autogenous material available for the large number of patients. Consequently, an allogeneic bone bank is an attractive alternative. However, allogeneic bone has limitations that can include viral contamination and possible postoperative complications. Alternatives to autogenous and allogeneic preparations include a variety of biocompatible materials, such as calcium phosphates, biologically active glass, polymers and several combinations of bone derivatives, usually based on collagen. Combinations of biomaterials and growth factors are sometimes used.
The biocompatible materials, listed in previous section, constitute the basis for tissue engineering of bone. Tissue-engineered bone substitute is composed of (a) a scaffold, formed of biocompatible and biodegradable material, (b) cells with osteogenic potential and, optionally, (c) signal molecules that will promote cell recruitment, mitogenesis, differentiation and renewal.