Biodentine Stimulates Calcium-Dependent Osteogenic Differentiation of Mesenchymal Stromal Cells from Periapical Lesions

Biodentine, a tricalcium silicate cement, has emerged as a retrograde root-end filling material to promote periapical lesion (PL) healing after apicoectomy. However, its underlying mechanisms remain unclear. This study tested the hypothesis that Biodentine stimulates the osteogenic differentiation of mesenchymal stromal cells (MSCs) derived from PLs. The Biodentine extract (B-Ex) was prepared by incubating polymerized Biodentine in RPMI medium (0.2 g/mL) for three days at 37 °C. B-Ex, containing both released microparticles and soluble components, was incubated with PL-MSCs cultured in either a basal MSC medium or suboptimal osteogenic medium. Osteogenic differentiation was assessed by Alizarin Red staining and the expression of 20 osteoblastogenesis-related genes. Non-cytotoxic concentrations of B-Ex stimulated the proliferation of PL-MSCs and induced their osteogenic differentiation in a dose-dependent manner, with a significantly enhanced effect in suboptimal osteogenic medium. B-Ex upregulated most early and late osteoblastic genes. However, the differentiation process was prolonged, as indicated by the delayed expression of wingless-type MMTV integration site family member 2 (WNT2), bone gamma-carboxyglutamate protein (BGLAP), bone morphogenic protein-2 (BMP-2), growth hormone receptor (GHR), and FOS-like 2, AP-1 transcription factor subunit (FOSL2), compared with their expression under optimal osteogenic conditions. The stimulatory effect of B-Ex was primarily calcium dependent, as it was reduced by 85% when B-Ex was treated with the calcium-chelating agent EGTA. In conclusion, Biodentine promotes the osteogenic differentiation of PL-MSCs in a calcium-dependent manner, supporting its stimulatory role in periapical healing.