Honeycomb scaffolds capable of achieving barrier membrane-free guided bone regeneration

Barrier membrane-free guided bone regeneration (GBR) with a synthetic scaffold may resolve the current challenges in vertical bone augmentation. To realize such GBR, we fabricated carbonate apatite honeycomb (HC) scaffolds capable of preventing soft tissue invasion and enhancing bone ingrowth. These HC scaffolds with 230-, 460-, and 630 μm-aperture channels were designated as HC230, HC460, and HC630, respectively. They were constructed by interconnecting carbonate apatite microspheres; they possessed micropores and nanopores in the struts and were implanted on the rabbit calvarium. The amount of new bone and soft tissues in the HC scaffolds significantly increased and decreased, respectively, with the decrease in the channel aperture size. The new bone height in HC230 at 4 and 12 weeks post-implantation was 3.4 ± 0.5 and 3.8 ± 0.2 mm, respectively, reaching the top edge of the struts. The percent volume of new bone in HC230 at 4 and 12 weeks post-implantation was 38.6% ± 2.2% and 49.9% ± 1.5%, respectively. These findings demonstrated that HC230 augmented faster, higher, and a greater amount of vertical bone growth than the reported combinations of scaffolds and growth factors or barrier membranes. Therefore, the multiscale-architectural control of HC scaffolds may pioneer barrier membrane-free GBR.