3D bio-printing of photocrosslinked anatomically tooth-shaped scaffolds for alveolar ridge preservation after tooth extraction

Alveolar ridge preservation techniques have been developed as a possible method to maintain the optimum ridge contour and dimensions. Grafting a bone substitute is paramount to prevent alveolar ridge resorption after tooth extraction. However, it remains a great challenge to develop alveolar ridge preservation materials with sufficient mechanical strength, bioactivity, and osteoinductivity and favorable tooth extraction socket morphological matching. In this work, a novel photocrosslinked composite ink consisting of nacre, polyurethane (PU) and polyhedral oligomeric silsesquioxane (POSS) was prepared and used to fabricate 3D porous scaffolds for alveolar ridge preservation. This nacre/PU/POSS (NPP) composite was characterized in terms of its rheological behavior, mechanical properties, and surface hydrophilicity. The biomineralization of these NPP scaffolds was confirmed via in vitro experiments. MC3T3-E1 cells were distributed homogeneously on the NPP scaffolds and stimulated cellular proliferation. When the NPP scaffolds were grafted into the sockets after extraction of mandibular incisors, the height and width of alveolar bone resorption were reduced, and new bone formation was observed. These NPP composites are promising scaffold materials for alveolar ridge preservation and 3D printing of bone grafts in future.