Survival of human dental pulp cells after 4-week culture in human tooth model

OBJECTIVES: This study aimed to validate the human tooth model by investigating the growth efficiency, expression of mesenchymal stem cell (MSC) markers and differentiation ability of human dental pulp cells (hDPCs) harvested from extracted immature third molars and cultured for different periods. Moreover, the effect of exposure and capping with a hydraulic calcium-silicate cement on pulp tissue after 4-week culture in the tooth model was investigated. METHODS: Primary hDPCs were collected from 18 molars from six individuals (15-19 years). One tooth of each patient was immediately cultured (control), while the other teeth were exposed to culture medium for 1, 2 or 4 weeks. After different culture periods, cells were harvested using the explant method, upon which cells were evaluated for cell-doubling time, colony-forming efficiency and expression of cell surface markers. The osteogenic, adipogenic and chondrogenic differentiation efficacy was also determined. Two teeth from three different patients (n = 6) were used for the pulp-capping assay. Three teeth were capped with ProRoot MTA (Dentsply Sirona), while three other exposed teeth remained uncapped (control). RESULTS: Cells were found to grow, express MSC markers and showed osteogenic, adipogenic and chondrogenic differentiation potential at all time periods. Histology of the teeth subjected to the pulp-capping assay showed the formation of mineralized tissue after 4-week exposure to ProRoot MTA (Dentsply Sirona) and normal histological features in the control teeth. CONCLUSIONS: This study confirmed that hDPCs of teeth cultured for up to 4 weeks in a human tooth model are viable, express MSC markers and show differentiation ability. CLINICAL SIGNIFICANCE: The human tooth model can be seen as an advanced cell-culture model that makes use of the original 3D pulp-chamber structure. It can serve as a screening tool to evaluate new pulp-capping formulations in a relatively cheap and fast manner.