Three-Dimensionally Printed Polyetherketoneketone Scaffolds With Mesenchymal Stem Cells for the Reconstruction of Critical-Sized Mandibular Defects

Objective: Additive manufacturing offers a tailored approach to tissue engineering by providing anatomically precise scaffolds onto which stem cells and growth factors can be supplied. Polyetherketoneketone (PEKK), an ideal candidate biomaterial, is limited by a poor implant-bone interface but can be functionalized with adipose-derived stem cells (ADSC) to promote integration. This in vivo study examined the interaction of a three-dimensional printed PEKK/ADSC implant within the critical-sized mandibular defect in a rabbit model. Study Design/Methods: Trapezoidal porous scaffolds with dimensions of 1.5 x 1.0 x 0.5 cm were printed using selective laser sintering. ADSCs were seeded on the scaffolds that were then implanted in marginal defects created in New Zealand rabbits. Rabbits were euthanized at 10- and 20-week intervals. Microcomputed tomography was used to characterize bone ingrowth and was correlated with histological analysis. Stress testing was performed on the scaffolds before and after implantation. Results: All scaffolds were well integrated into adjacent bone. Bone-to-tissue volume increased from 30.34% (+/- 12.16) to 61.27% (+/- 8.24), and trabecular thickness increased from 0.178 mm (+/- 0.069) to 0.331 mm (+/- 0.0306) in the 10- and 20-week groups, respectively, compared to no bone regrowth on the control side (P < 0.05). Histology confirmed integration at the bone-implant interface. Biomechanical testing revealed a compressive resistance 15 times that of bone alone (P<0.05) Conclusion: 3D-printed PEKK scaffolds combined with ADSCs present a promising solution to improve the bone implant interface and increase the resistance to forces of mastication after mandibular reconstruction.