Hypoxia inhibits mineralization ability of human dental pulp cells treated with TEGDMA but increases cell survival in accordance with the culture time

• TEGDMA treated human dental pulp cells were grown in the presence of 3% or 21% O2.
• Hypoxia leads to increase in the survival of pulp cells against TEGDMA.
• Hypoxia decreases the odontoblastic differentiation of pulp cells.
• TEGDMA causes considerable oxidative stress on human dental pulp cells.

ObjectiveTo evaluate the cytotoxicity and mineralization effects of TEGDMA in human dental pulp cells (hDPCs) under hypoxic and normoxic culture conditions.DesignCell viability was evaluated using XTT assay after incubation periods of 24, 48, or 72 h. The expression of mineralization-related genes (osteonectin, osteopontin, dentin sialophosphoprotein, collagen type 1) and heme oxygenase 1 (HO-1) was assessed by quantitative real-time polymerase chain reaction at 24 and 72 h.ResultsIn XTT assay, viability was higher in 0.3, 1, 2, 4, and 5 mM groups in the presence of 21% O2 after 24 h (p < 0.05). Additionally, while 0.3, 1, 2 mM groups had higher cell viability in the presence of 21% O2 after 48 h (p < 0.05), in 3 mM groups cell viability was higher under 3% O2 than 21% O2 after both 24 and 48 h (p < 0.05). 1–3 mM groups had higher cell viability under 3% O2 after 72 h (p < 0.05). There was no difference between 4 and 5 mM groups with regards to cell viability after 48 or 72 h (p > 0.05). In the gene expression study, TEGDMA-treated hDPCs showed lower mineralization potential in the presence of 3% than with 21% O2 (p < 0.05). hDPCs revealed higher HO 1 expression in 0.3 and 1 mM groups under hypoxic than under normoxic conditions after a 72-h time period (p < 0.001).ConclusionsHypoxic conditions increased cell survival in accordance with the culture period but inhibited the odontoblastic differentiation of hDPCs treated with TEGDMA.