Composite scaffold with demineralized dentin particle and poly(lactic co- glycolic acid) for cranial bone regeneration

In the present study, we prepared a composite scaffold of demineralized dentin particles (DDPs) with poly(lactic co-glycolic acid) (PLGA) to investigate cranial bone regeneration. We first determined protein and elemental contents in DDPs demineralized with ethylenediamine-tetraacetic acid (EDTA) and guanidine-hydrochloride (Guanidine-HCl) in order to obtain DDPs with high protein contents which might stimulate osteogenesis. Compared to Guanidine-HCl, DDPs obtained with EDTA showed smooth surface morphologies, increased net protein contents and elements per unit weight, and retained the spectral intensity of NH2 bonding. The treatment of DDPs obtained with EDTA to dental pulp stem cells (DPSCs) and bone marrow stromal cells (BMSCs) supported cell growth, and, in combination with osteogenic (OS) medium, enhanced alkaline phosphatase activity and mineral deposition at the range of 1∼10 μg DDP/cm² in vitro. To manipulate DDPs as a sheet form of scaffolds, composite scaffolds containing 1, 3, 5 and 10 wt% of DDPs with PLGA were prepared with a salt leaching method. In vitro analysis showed that PLGA composite scaffolds containing 1 and 3 wt% DDPs enhanced cell adhesion and expression of osteogenic marker genes. In animal model with calvarial defects, the PLGA composite scaffold containing 3 wt% DDPs seeded with DPSCs showed enhanced calvarial bone regeneration. Therefore, we suggest that DDPs prepared with EDTA and the composite scaffolds with PLGA could be a useful material for cranial bone regeneration.