mean ± standard deviation (SD).

It also seems as if the compressive strength resistance of both strand orientations is significantly lower when the strength is applied laterally. Nevertheless, all investigated scaffolds have shown a higher energy absorption in comparison with the control group (BioOss®).

#### *3.4. Preliminary Investigations of Individual Scaffolds for Clinical Cases*

For the manufacturing of patient-specific scaffolds in order to reconstruct individual bone defects, a high-resolution model of the defect site is necessary. Based on patients' computed tomography data, irregular shaped macroporous scaffolds were designed in close collaboration with maxillofacial surgeons via digital backward planning. For this study, we analyzed different clinical cases—sinus floor elevation and onlay osteoplasty—in different regions, shapes and sizes (Figure 8).

**Figure 8.** Digital backward planning based on CBCT data. (**a**) Sinus floor elevation in region 26, (**b**) bilateral onlay graft in the posterior mandible (white: prosthetic restoration; yellow: dental implant; orange: bone contour; blue: planned CPC scaffold.

According to the anatomical requirements of the defect site, the digital planned scaffolds were printed by INNOTERE GmbH (Radebeul, Germany). Since blood and bone cells are expected to migrate into the scaffold from the prepared adjacent bone, the bone-facing part of the scaffolds was printed with the approved pore size of 0.49 mm and a strand distance of 0.82 mm. To avoid fibroblasts or keratinocytes infiltrating the scaffold from the soft tissue facing side, this part was printed with a strand distance of 0.3 mm (Figure 9) to achieve a similar effect to that of using the membrane technique.

**Figure 9.** Individual scaffold for sinus floor elevation (**a**–**c**) and two onlay grafts in the lower jaw (region 36, 46: (**d**–**f**); region 47: (**g**–**i**)).

The mechanical properties of the individual scaffolds were tested by conducting uniaxial compression tests. Data are shown in Table 3.


**Table 3.** Mechanical properties of patient individual scaffolds and control group.
