Novel metformin-containing resin promotes odontogenic differentiation and mineral synthesis of dental pulp stem cells

OBJECTIVES. This represents the first report on the development of metformin-containing dental resins. The objectives were to use the resin as a carrier to deliver metformin locally to stimulate dental cells for dental tissue regeneration, and to investigate the effects on odontogenic differentiation of dental pulp stem cells (DPSCs) and mineral synthesis. METHODS. Metformin was incorporated into a resin at 20% by mass as a model system. DPSC proliferation attaching on resins was evaluated. Dentin sialophosphoprotein (DSPP), dentin matrix phosphoprotein 1 (DMP-1), alkaline phosphatase (ALP) and runt-related transcription factor 2 (Runx2) genes expressions were measured. ALP activity and alizarin red staining (ARS) of mineral synthesis by the DPSCs on resins were determined. RESULTS. DPSCs on metformin-containing resin proliferated well (mean ± SD; n = 6), and the number of cells increased by 4 folds from 1 to 14 days (p > 0.1). DSPP, ALP and DMP-1 gene expressions of DPSCs on metformin resin were much higher than DPSCs on control resin without metformin (p < 0.05). ALP activity of metformin group was 70% higher than that without metformin at 14 days (p < 0.05). Mineral synthesis by DPSCs on metformin-containing resin at 21 days was 9 folds that without metformin (p < 0.05). SIGNIFICANCE. A novel metformin-containing resin was developed, achieving substantial enhancement of odontoblastic differentiation of DPSCs and greater mineral synthesis. The metformin resin is promising for deep cavities and perforated cavities to stimulate DPSCs for tertiary dentin formation, for tooth root coatings with metformin release for periodontal regeneration, and for root canal fillings with apical lesions to stimulate bone regeneration.