Method: Pulp cells were isolated from human third molars by the outgrowth method and cultivated in MEM medium. Samples of BiodentineTM: a dentin substitute mainly composed of tricalcium silicates and TheraCal™LC: a light-cured composite material of calcium silicates and resinous components were prepared according to the manufacturers’ instructions. They were dipped into the culture media at 0.05 or 0.5 cm2/mL for 24 hours and 3 days (toxicity) or for 3, 5 and 7 days (proliferation) before applying the MTT test. Pro-inflammatory cytokine IL-8 was quantified by ELISA, after stimulating the cells with LTA for 4 hours and their incubation for additional 2 and 4 hours with media containing the materials eluates (0.05 cm2/mL). Untreated cells were used as controls.
Result: Increasing TheraCal™LC surface area from 0.05 to 0.5 cm2/mL significantly increased its toxicity from 20% to 40% respectively and significantly decreased pulp cell proliferation to reach less than 20% of the initial cell number (p<0.05). Biodentine™ had no significant toxicity nor affected cell proliferation. After LTA stimulation for 4 hours, IL-8 secretion in the presence of Biodentine™ conditioned medium was same as the control but that in presence of TheraCal™LC was twice higher than that with Biodentine™ (P<0.05).
Conclusion: Adding resinous components to tricalcium silicates induces toxic effects to target cells. They inhibit pulp cell proliferation and induce a significant secretion of IL-8 which might compromise the pulp regeneration capacity. Clinical significance: resin-based materials cannot be recommended for direct pulp capping.