Bone regenerative performance of an in silico optimized 3D-printed ceramic scaffold in a canine model using X-ray microtomography analysis

Background & Aim: Patient specific 3D-printed ceramic scaffolds represent a promising solution to reconstruct large intra-oral bone defects. Although the scaffold internal design is known to influence the biomaterial regenerative performances, in silico modelling is largely underused to optimize it. This in vivo study aimed to evaluate the bone regenerative performance of a hydroxyapatite-based 3D-printed scaffold with an in silico optimized internal design compared to a xenogenic bone block in a canine model.
Materials and Methods: A three walls standardized alveolar bone defect was created at each hemimandible of 16 male Beagles. After a healing period of 12 weeks, each bone defect was either filled with a dog-specific optimized 3D-printed ceramic scaffold (test group) or a hand-carved Cerabone® block (control group). Animals were euthanized at 6 and 12 weeks post-implantation and the bone regenerative performance was assessed by micro-computed tomography (microCT).
Results: A few weeks post-implantation, half of the animals presented biomaterial dehiscence or moderate inflammation and were therefore assigned to the 6 weeks group. The microCT analysis revealed a higher percentage of newly formed bone in the 3D-printed scaffold compared to the control group (p<0.05). Twelve weeks post-implantation, three 3D-printed scaffolds were broken and almost totally lost. Both groups displayed a significant increase of newly formed bone from 6 to 12 weeks (p<0.001 for control group and p<0.05 for the test group) but no difference was observed between the 2 groups at 12 weeks.
Conclusion: The hydroxyapatite-based 3D-printed scaffold with an in silico optimized internal design was associated to an early stage enhanced bone regenerative performance compared to the xenogenic control block. However, further developments are required in order to improve its mechanical properties as well as adaptations of its external dimensions and the surgical technique to avoid future complications such as biomaterial exposures.