An evaluation of the inflammatory response of lipopolysaccharide-treated primary dental pulp cells with regard to calcium silicate-based cements

This study compared the biological changes of lipopolysaccharide (LPS)-treated dental pulp (DP) cells directly cultured on mineral trioxide aggregate (MTA) and calcium silicate (CS) cements. DP cells were treated with LPS for 24 h. Then, the LPS-treated DP cells were cultured on MTA or CS cements. Cell viability, cell death mechanism and interleukin (IL)-1β expressions were analysed. A one-way analysis of variance was used to evaluate the significance of the differences between the means. A significantly higher IL-1β expression (2.9-fold) was found for LPS-treated cells (P<0.05) compared with DP cells without LPS treatment at 24 h. Absorbance values of LPS-treated cells cultured on CS cement were higher than a tissue culture plate. A significant difference (P<0.05) in cell viability was observed between cells on CS and MTA cements 24 h after seeding. At 48 h, a high concentration of Si (5 mM) was released from MTA, which induced LPS-treated DP cell apoptosis. The present study demonstrates that CS cement is biocompatible with cultured LPS-treated DP cells. MTA stimulates inflammation in LPS-treated DP cells, which leads to greater IL-1β expression and apoptosis. A new cement for tooth root repair may offer better biocompatibility and lower risk of inflammation than currently used materials. Mineral trioxide aggregate (MTA) has proven highly effective for endodontic repair procedures, but Ming-You Shie and colleagues at Taiwan’s Chung Shan Medical University have developed a calcium silicate (CS) cement that may prove safer. To simulate conditions in the mouth, they cultured dental pulp cells on both MTA and CS, and exposed them to a toxic compound produced by oral bacteria. Cells cultured on MTA exhibited an elevated and prolonged inflammatory response, possibly arising from silicon released from MTA. In contrast, cells cultured on CS showed improved viability and reduced inflammation over time. The researchers propose that this new cement may offer a useful alternative to MTA.