Ti­ta­ni­um bone scaf­folds, FHNW School of Life Sciences

The treatment of large bone defects still poses a major challenge in orthopaedic and craniomaxillofacial surgery. One possible solution is the development of personalised porous titanium based implants, designed to meet all mechanical needs with a minimum amount of titanium and maximum of osteopromotive properties.

In this project, we developed specific designs of unit cells to fill out bony defect sites with an open-porous lattice structure. The mechanic response of the scaffold depends on the chosen lattice architecture. This is of great importance for mimic human bone by titanium scaffolds in order to reduce stress shielding.

The designed titanium scaffolds were 3D-printed by selective laser melting and then implanted into calvarial defects in rabbits to examine bone formation and osseointegration. Significant differences are noted between defects filled with implants and untreated defects.

The studies further aimed to apply SLM that allows a high degree of microarchitectural freedom to generate lattice structures and to determine the optimal distance between rods and the optimal diameter of rods for osteoconduction (bone ingrowth into scaffolds) and bone regeneration.

For the biological readout, diverse SLM-fabricated titanium implants were placed in the calvarium of rabbits and new bone formation and defect bridging were determined after 4 weeks of healing.

To link 3D scaffold architecture to biological readouts, bone ingrowth, bone to implant contact, and defect bridging of noncritical-sized defects in the calvarial bone of rabbits were determined.

We further elucidated the optimal microarchitecture for osteoconduction and determine compression strength and Young’s Modulus of the selected architectures.