Background and objectives: The aim of the study was to examine feasibility of craniomaxillofacial bone tissue reconstruction with the help of custom-made CAD/CAM-based stem-cell-seeded composite scaffolds.
Methods: Tricalcium phosphate (TCP) scaffolds (20 mm × 10 mm diametre) with channels measuring 500 ‘micrometre’ in cross sections were fabricated by means of 3D-printing. Subsequently, the scaffolds were infiltrated with polyhydroxybutyrate (PHB) in order to manufacture a composite tricalcium phosphate/polyhydroxybutyrate (TCP–PHB) scaffold. Mesenchymal stem cells (MSCs) were seeded onto the scaffolds and osteogenic differentiation was performed. Biomechanical properties (compressive strength) determined with a uniaxial testing system as well as cell proliferation (WST-assay) and cell survival (live-dead-assay) were analyzed. Osteogenic differentiation was assessed with alkaline phosphatase activity on protein level in 3D culture. Additionally, needle-type oxygen microsensors were used to study oxygen levels within the scaffolds.
Results: Biomechanical properties were significantly improved based on the polymer infiltration procedure (3.41 ± 0.71 MPa vs. 1.92 ± 0.38 MPa). Cells attached on the scaffolds and cell survival rate was 94 ± 5%. Results of WST-assay indicate a continuous 3-fold increase over a time period of 21 days. Osteogenic differentiation into the osteogenic lineage was confirmed. The oxygen supply did not severely decrease also in the central areas of scaffolds after 8 days.
Conclusion: Custom-made vitalized TCP–PHB scaffolds are a promising option for tissue engineering, offering suitable mechanical and biological properties. Moreover, CAD/CAM technique enables detailed reconstruction of complex 3-dimensional craniomaxillofacial structures making the concept potentially applicable for a variety of clinical relevant bone defects.
Key words: bone tissue engineering; mesenchymal stem cells; CAD/CAM; tricalcium phosphate