LAUSR

INTRODUCTION Vital pulp therapy is aim at preserving pulp vitality and regenerating dentin. Therefore, the purpose of this study was to explore the effects of a combination of treated dentin matrix (TDM) proteins and dental pulp cell-derived small extracellular vesicle (sEV) on pulp-dentin complex repair. METHODS We prepared TDM by chemical demineralization and mechanical disruption of teeth to a powder preparation. The sEV were isolated from culture supernatants of dental pulp cells (DPCs) and identified by nanoparticle tracking analysis, western blotting, and transmission electron microscopy. The effect of a combination of TDM proteins and dental pulp cell-derived sEV on DPCs' proliferation, migration and odontogenic differentiation was evaluated in vitro. A mini-pig model of pulp injury was used to compare the clinical outcomes and tissue responses attributed to four materials including TDM, sEV-TDM, sEV and mineral trioxide aggregate (MTA). RESULTS The sEV isolated from the cell supernatant promoted DPCs proliferation and migration. The combination of TDM extracts and sEV synergistically promoted the migration of DPCs but suppressed their proliferation. RT-PCR and Western blot revealed that sEV-TDM enhanced the odontoblast related protein expressions in DPCs. In vivo studies, TDM and sEV-TDM promoted the formation of continuous reparative dentin. Furthermore, odontoblast-like high columnar cells were observed on the pulp side of the dentin bridge. CONCLUSION The sEV-TDM complex exhibits intrinsic biological activities, which has potential applications as a bioactive pulp capping material.