Tricalcium Silicate Capping Materials Modulate Pulp Inflammatory Activity and Regeneration

Objectives: Initiation of pulp/dentin regeneration requires recruitment /proliferation of dental pulp stem cells to regenerate reparative dentin at the injury site, and pulp fibroblasts to replace the missing pulp. Due to its location within a rigid environment, the pulp regeneration success depends also on the pulp inflammation state.
This work was designed to investigate, in vitro, the regeneration and inflammatory potential of two pulp capping materials, Biodentine^™ (silicate-based) and TheraCal^® (silicates and resin-based).
Methods: Samples of materials were incubated in culture media to obtain conditioned media (0.05cm²/ml). The effects of these media were investigated on physically injured pulp fibroblasts after stimulation with lipoteichoic acid (LTA). The secretion of inflammatory cytokines and FGF2 were quantified by ELISA. Pro-inflammatory activation of vascular endothelium was studied using adhesion of fluorescence (BCECF)-labeled inflammatory THP-1 cells to endothelial cell (HUVECs) monolayers. THP-1 cell activation was studied using cell adhesion assay. Proliferation of fibroblasts was quantified using MTT assay and healing was studied using the monolayer scratch assay.
Results: Biodentine^™ induced a significantly higher secretion of FGF2 and anti-inflammatory cytokine TGFβ1, and a lower secretion of the pro-inflammatory cytokine IL6 compared to TheraCal^®. Supernatants of LTA-stimulated and injured fibroblasts incubated with Biodentine^™ drastically decreased THP-1 cell adhesion to HUVEC monolayer as well as the number of activated THP-1 cells. TheraCal^® slightly decreased THP-1 adhesion and activation. When fibroblasts were grown in supernatants of LTA-stimulated and injured fibroblasts in Biodentine^™ conditioned media, an increased fibroblast proliferation was observed. On the contrary, this proliferation decreased with TheraCal^®. Moreover, only supernatants of LTA-stimulated and injured fibroblasts in Biodentine^™ conditioned media increased monolayer healing with the scratch test.
Conclusions: These results performed in vitro show that Biodentine^™ has higher anti-inflammatory and regeneration potential than resin-containing materials such as TheraCal^®.