No abstract

Bone tissue engineering utilizing biomaterials to improve osteoblast growth has provided de novo consideration for therapy of bone diseases. Polypropylene carbonate (PPC) is a polymer with a low glass transition temperature but high elasticity. In this study, we developed a new PPC-derived composite by mixing poly-lactic acid (PLA) and tricalcium phosphate (TCP), called PPC/PLA/TCP elastic (PPTE) scaffolds. We also evaluated the beneficial effects of PPTE composites on osteoblast growth and maturation and the possible mechanisms. Compared to PPC polymers, PPTE composites had similar pore sizes and porosities but possessed better hydrophilic surface structures. Biological evaluations further revealed that PPTE composites attracted adhesion of mouse osteoblasts, and these bone cells extended along the porous scaffolds to produce accurate fibroblast-like morphologies. In parallel, seeding mouse osteoblasts onto PPTE composites time-dependently increased cell growth. Sequentially, PPTE composites augmented DNA replication and cell proliferation. Consequently, PPTE composites significantly improved osteoblast mineralization. As to the mechanism, treatment with PPTE composites induced osteopontin (OPN) mRNA and protein expression and alkaline phosphatase activity. Taken together, this study showed that PPTE composites with porous and hydrophilic surfaces can stimulate osteoblast adhesion, proliferation, and maturation through an OPN-dependent mechanism. Therefore, the de novo PPTE scaffolds may have biomaterial potential for bone regeneration.

The use of this novel osteoconductive scaffold combined with osteoinductive platelet gel offers a valuable alternative for the reconstruction of calvarial bone defects.

No abstract

Sinus augmentation is a common approach for patients with severe alveolar ridge atrophy but an ideal material to increase the bone volume for dental implantation is still needed. The present study evaluated the effect of a newly developed polymeric bone-filling powder (formed from acrylic acid and N-isopropylacrylamide, ANa) mixed with platelet-rich plasma (PRP) for bone generation in a rabbit model of sinus augmentation. A total of 12 New Zealand White rabbits were randomly divided into three groups based on filling material. All animals underwent a bilateral maxillary sinus augmentation. PRP was prepared using an automatic separation system to obtain a high platelet concentration. ANa powder was individually mixed with phosphate-buffered saline (PBS) or PRP for sinus floor elevation. The left maxillary sinus received the ANa/PBS filling, whereas the right maxillary sinus received a mixture of ANa/PRP gel. Equal volumes of filling material were inserted in each maxillary sinus. Thus, defects with no implantation served as controls. Animals were sacrificed at 4 and 12 weeks, and then all specimens were harvested for micro-computed tomography (micro-CT) and histological analysis. On micro-CT evaluation, ANa/PRP significantly increased the bone volume in maxillary sinus augmentation relative to the negative control and ANa/PBS after 12 weeks. New bone areas with osteocytes and osteon formation were found in all three groups at 12 weeks post-implantation. This study confirms that ANa mixed with PRP can effectively increase the bone volume in the sinus cavity. This benefit for sinus augmentation may increase the success of dental implantation because of the formation of a thin layer of alveolar bone.