An anti-bacterial porous shape memory self-adaptive stiffened polymer for alveolar bone regeneration after tooth extraction

The regeneration of alveolar bone after tooth extraction is critical for the placement of dental implants.Developing a rigid porous scaffold with defect shape adaptability is of great importance but challenging for alveolar bone regeneration.Herein,we design and synthesize a biocompatible poly(L-glutamic acid)-g-poly(ε-caprolactone)(PLGA-g-PCL)porous shape memory(SM)polymer.The PLGA-g-PCL is then copolymerized with acryloyl chloride grafted poly(ω-pentadecalactone)(PPDLDA)having a higher phase transition temperature than shape recovery temperature to maintain stiffness after shape recovery to resist chewing force.The hybrid pol-ydopamine/silver/hydroxyapatite(PDA/Ag/HA)is coated to the surface of(PLGA-g-PCL)-PPDL scaffold to afford the anti-bacterial activity.The porous SM scaffold can be deformed into a compact size and administered into the socket cavity in a minimally invasive mode,and recover its original shape with a high stiffness at body tem-perature,fitting well in the socket defect.The SM scaffold exhibits robust antibacterial activity against Staphy-lococcus aureus(S.aureus).The porous microstructure and cytocompatibility of PLGA allow for the ingrowth and proliferation of stem cells,thus facilitating osteogenic differentiation.The micro-CT and histological analyses demonstrate that the scaffold boosts efficient new bone regeneration in the socket of rabbit mandibular first premolar.This porous shape memory self-adaptive stiffened polymer opens up a new avenue for alveolar bone regeneration.