Growth of Dental Pulp Stem Cell on Human Dentin Slices

One of the signaling molecules sequestered in extracellar matrix (ECM), transforming growth factor (TGF)- ß1, may stimulate tertiary dentin formation when it was exposed at a site of tooth injury. In order to understand the cells' reaction to TGF- ß1 during dentin repair, we grew dental pulp stem cells (DPSCs) on ECM with endogenous TGF- ß1 exposed to simulate the local environment of the tooth injury and study the cellular response. Objectives: Our goal of this experiment was to establish the growth kinetics of DPSCs on EDTA treated human dentin slices, as this has been suggested to expose TGF- ß1. Based on this result, we can then further study DPSC's cellular response on EDTA treated human dentin. Methods: Human third molar immature teeth were cut into 3 ~ 5 mm thick slices and treated with 17% EDTA for 3 min. Non EDTA treated dentin slices were used as control. The dentin slices were then seeded with DPSCs at an initial concentration of 140 cells/mm². The slices were cultured in Dulbecco's Modified Eagle Medium (DMEM) and incubated at 37^oC in air containing 5% CO₂ . Cells growing on three dentin slices from the control and the experimental groups were removed with trypsin and counted daily. Results: The cells on EDTA-treated dentin slices spent 4 days in lag phase. The cells then grew constantly up to 11 days of seeding and then reached a plateau phase with a cell density of 190 cells/mm². The control group showed similar growth kinetics but higher cell density of approximately 230 cells/mm² in the plateau phase. Conclusion: The DPSCs showed a slow growth curve on the human dentin slice and the cell density was lower than that seen in a culture dish. EDTA-treated dentin sections did not increase DPSCs' proliferation. Supported by NIDR Grant 12899.