In the publicly funded project Hybrid-Bone (VIP+ 03VP07633) the consortium is validating the manufacturing of customizable ceramic bone substitute materials and structures for improved regeneration in the facial skull region, in particular, as jawbone replacement [1]. Beforehand, the shape of the implant will be adapted regarding the individual geometry as well as the mechanical requirements using computer-aided calculation and simulation. Based on that a scaffold will be developed using a combination of different additive manufacturing (AM) processes to achieve load-specific and topology optimized support structures and a foaming process for realizing a bone-mimicking artificial spongiosa [2,3]. 
In a first step, the support structure will be printed by AM (CerAM Vat-Photopolymerization & Binder Jetting). In the second step it will be foamed-in with a porous and degradable calcium phosphate ceramic that mimics the shape of the jaw. For this purpose, Fraunhofer IKTS uses a process known as Freeze Foaming, which allows the foaming of any powdery material and the foaming-in into near-net-shape structures. In a joint heat treatment both structural components finally fuse to form a hybrid bone construct.
Next to the pure calcium phosphate ceramic other biocompatible materials and hybrids of thereof will be manufactured, such as a titanium alloy-ceramic and a hydroxyapatite (HA)-zirconia composite.
On our way to the final hybrid jawbone demonstrator (Figure 1 left), previously designed experimental load-bearing support structures were manufactured by AM (CerAM VPP) using HA ceramic (Co. Merck KGaA former Sigma-Aldrich, BET = 70.01 m2/g, d50 = 2.64 µm). Those then were foamed-in using the Freeze Foaming of HA suspension. After the co-sintering step first “hybrid bones” resulted (resembled by Figure 1 right) which are now tested regarding their in-vitro behaviour. The next composites will be TiAl6V4-HA and HA-ZrO2 hybrid foams soon to be tested in vitro and later this year in vivo. In the future, the applied procedure shall be transferable to other bone structures located, for example, in the spine or in the limbs.