The combined application of rat bone marrow mesenchymal stem cells and bioceramic materials in the regeneration of dental pulp-like tissues.

This study aims to observe the effects of the combined application of rat bone marrow mesenchymal stem cells (rBMSCs) and a bioceramic material on pulp-like tissue formation. Rat incisor root fragments without pulp tissues were prepared and filled with a collagen scaffold seeded with rBMSCs, while one side of the root segment was covered by a bioceramic material (iRoot BP). After they were cultured for 12 hours, the root fragments were implanted subcutaneously for 3 months. Hematoxylin and eosin (HE) staining was applied to observe the biocompatibility and the formation of pulp-like tissues. The incisor root fragments were divided into three parts (BP1/3, M1/3, and D1/3) to analyze the areas and the number of new vessels. Immunohistochemical staining of the neuroendocrine marker PGP9.5, the dentin sialophosphoprotein (DSPP), and the vascular endothelial growth factor (VEGF) was applied to observe the formation of the pulp-like tissues. Root fragments filled with only the collagen scaffold were used as a control. Three months after the implantation, the root fragments were collected, and they were surrounded by a transparent tissue membrane with a good blood supply. The root fragment cavity was filled with pink vascularized pulp-like tissue. According to the HE results, iRoot BP had good biocompatibility with the new pulp-like tissues and a few infiltrating inflammatory cells. Increases in the number and area of the new blood vessels were observed in BP1/3 compared with the other two parts. The PGP9.5 and DSPP expressions showed that the newly formed tissues were similar to normal pulp tissues. iRoot BP has good biocompatibility and increases the number and area of new blood vessels. The combined application of stem cells and bioceramic materials may be a better method for pulp revascularization.