Human dental pulp stem cell response to a novel photoinitiator for resin-based dental materials

This study aimed to assess the cytotoxicity of a novel polymerization initiator, tert-butyl (tert-butyldimethylsilyl) glyoxylate (DKSi), and its effect on cytokine release by human dental pulp stem cells (hDPSCs), compared with camphorquinone (CQ) and diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO). hDPSCs were isolated from healthy third molars, seeded in 96-well plates, and exposed to initiators diluted in dimethyl sulfoxide (0.1-6 mM) for 24 h. Mitochondrial metabolism was assessed by the MTT assay, and cytokine release (interleukin-1 beta, interleukin-6 [IL-6], interleukin-8 [IL-8], interleukin-10, and tumor necrosis factor alpha [TNF-α]) was analyzed using the MAGPIX system. Untreated cells served as controls, and data were analyzed using two-way anova and Tukey's test. All compounds showed low toxicity at lower concentrations, whereas 6 mM caused the greatest reduction in mitochondrial metabolism. DKSi also exhibited significant toxicity at 4 mM. Unlike CQ and TPO, DKSi did not promote cytokine release. TPO upregulated all cytokines tested, and CQ increased TNF-α, IL-6, and IL-8. DKSi showed significant cytotoxicity only at high concentrations and a more limited modulation of cytokine release than CQ and TPO. These findings provide an initial biological characterization of DKSi and support its further investigation as a potential photoinitiator for dental resin formulations.