The lack of sources for autologous bone transplantation has lead to the development of different strategies for bone replacement, one presented by biological and alloplastic bone substitute materials with and without the additional application of growth factors (bone regeneration). Until now, however, the autologous bone has been considered to be the absolute and unrivalled gold standard. Alternatively, to accomplish complete osseous defect regeneration, tissue engineering,1–8 i.e., the implantation of scaffolds seeded in vitro with autologous cells, has been proposed. The use of bone substitute materials has the intention to provide a framework for the ingrowing of mesenchymal cells with osteoblastic differentiation9 in terms of osteoconductivity or osteoinductivity.10 Thereby it is aimed that the primarily avital scaffold material will be replaced by functional, vital bone tissue. Of particular importance within that context are polymer-composite materials,11 which are either based on biodegradable or non-degradable polymers. These provide both the (cell-loaded) polymeric scaffold as well as the inorganic material, for example, hydroxyapatite (HA) that facilitates the formation of osseous tissue. In first clinical applications in preprosthetic augmentation procedures of the maxilla,12 however, ossification was often incomplete, although the sinus lift defect actually offers ideal conditions for bone transplantation and regeneration.13 In fact, so far the results have not been better than those obtained by the use of alloplastic bone substitute materials alone, such as HA. Possible reasons for the failure are manifold and include insufficiencies of the scaffold materials in terms of chemistry and mechanics, the lack of osteogenic stimuli and the problem of nutrition and vascularization. Collagenous products lack mechanical stability, besides the unsolved problem of senzitation. In addition, inorganic materials with high mechanical stability such as HA,14, 15 tricalciumphosphate (TCP),16, 17 and other ceramics, are replaced only insufficiently by vital bone and are often integrated by fibrous, scar-like tissue. This is not surprising, since the exceptional properties of bone material are the consequence of very subtle (sub-) structures that strongly depend on mineral morphologies and orientation as well as on crystallinity,18 which are all to be controlled during growth, i.e., in vivo19 and not in vitro.