Cell death effects of resin-based dental material compounds and mercurials in human gingival fibroblasts

Abstract

In order to test the hypothesis that released dental restorative materials can reach toxic levels in human oral tissues, the cytotoxicities of the resin-based dental (co)monomers hydroxyethylmethacrylate (HEMA), triethyleneglycoldimethacrylate (TEGDMA), urethanedimethacrylate (UDMA), and bisglycidylmethacrylate (BisGMA) compared with methyl mercury chloride (MeHgCl) and the amalgam component mercuric chloride (HgCl2) were investigated on human gingival fibroblasts (HGF) using two different test systems: (1) the modified XTT-test and (2) the modified H 33342 staining assay. The HGF were exposed to various concentrations of the test-substances in all test systems for 24 h. All tested (co)monomers and mercury compounds significantly (P<0.05) decreased the formazan formation in the XTT-test. EC50 values in the XTT assay were obtained as half-maximum-effect concentrations from fitted curves. Following EC50 values were found (mean [mmol/l]; s.e.m. in parentheses; n=12; * significantly different to HEMA): HEMA 11.530 (0.600); TEGDMA* 3.460 (0.200); UDMA* 0.106 (0.005); BisGMA* 0.087 (0.001); HgCl2* 0.013 (0.001); MeHgCl* 0.005 (0.001). Following relative toxicities were found: HEMA 1; TEGDMA 3; UDMA 109; BisGMA 133; HgCl2 887; MeHgCl 2306. A significant (P<0.05) increase of the toxicity of (co)monomers and mercurials was found in the XTT-test in the following order: HEMA < TEGDMA < UDMA < BisGMA < HgCl2 < MeHgCl. TEGDMA and MeHgCl induced mainly apoptotic cell death. HEMA, UDMA, BisGMA, and HgCl2 induced mainly necrotic cell death. The results of this study indicate that resin composite components have a lower toxicity than mercury from amalgam in HGF. HEMA, BisGMA, UDMA, and HgCl2 induced mainly necrosis, but it is rather unlikely that eluted substances (solely) can reach concentrations, which might induce necrotic cell death in the human physiological situation, indicating that other (additional) factors may be involved in the induction of tissue (pulp) inflammation effects after dental restauration.

NAC ameliorates dental composite-induced DNA double-strand breaks and chromatin condensation

“…This effect may be linked to the high molecular weight of Bis-GMA relative to ACR (Table 1), since in dental (co)monomers a direct correlation between increasing molecular weight and the degree of cytotoxicity has been observed 64,65) ( Table 1). HEMA and TEGDMA were up to 110-fold less toxic than Bis-GMA, whereas HEMA was less toxic than TEGDMA, in agreement to former own results 65) . This can be explained by the more hydrophilic character of HEMA, which has an additional hydroxyl group compared with TEGDMA.…”

In VitroComparison of the Effects of Dental Filling Materials on Mouse Fibroblasts

“…Mohsen et al (34) determined that different aging procedures increased the biocompatibility of composites (42).…”

Heavy metals, islet function and diabetes development

“…98 The study of Nakagawa has shown that the total mercury concentrations in the hair of ordinary diseased people, including diabetes, were from 2.08 to 36.5 ppm; those values were considerably higher than that of healthy people of the same age-groups. 99 Organic or inorganic mercury compounds are well known to induce cellular damage in various cell types, such as renal cells, 92 astrocytes, 100 lymphoma cells, 101 human gingival fibroblast cells, 102 alveolar epithelial cells 103 and pancreatic islet β-cells. 104 Except for organic and inorganic forms of mercury toxicity, many studies focus on the vaccine preservative-thimerosal.…”