Ecotoxic and genotoxic potential of eluates from dental composite dust - an in vitro study

This study investigated the ecotoxic and genotoxic effects of composite components after grinding.

Samples of composite materials Ceram.x Spectra® ST (CX) and Filtek™ Supreme XTE (FS) were ground to dust in a plexiglas box with a standard diamond bur (106 µm). Aqueous (≤ 5 mg/mL) and organic (≤ 790 mg/mL) extracts were prepared to mimic wastewater samples. Ecotoxicity was assessed in luminescent bacteria (Vibrio fischeri), algae (Desmodesmus subspicatus), water flea (Daphnia magna), and fish embryo (Danio rerio). Genotoxicity was evaluated in human lung adenocarcinoma cells (A459) using the Comet assay. All statistical analyses were conducted using a significance level of α = 0.05.

Both materials inhibited V. fischeri bioluminescence; CX aqueous eluates showed significantly stronger effects than FS at 2.5 mg/mL (p < 0.01) and 1.25 mg/mL (p < 0.05). Organic extracts were similarly potent (EC50 ≈ 0.27-0.28 mg/mL) without significant differences. In algae, CX aqueous eluates caused significantly higher growth inhibition at all concentrations than FS (p < 0.01); CX organic extracts completely suppressed growth. In Daphnia, CX aqueous eluates caused 100% immobilization, while FS showed no effect. In fish embryos, CX aqueous eluates induced up to 100% mortality (≥ 1.33 mg/mL), whereas FS caused no mortality but impaired pigmentation. Organic extracts of both materials induced embryo mortality up to 100% at 2 mg/mL. No biologically relevant genotoxicity was found.

Both composites exhibit concentration-dependent ecotoxic effects across aqueous organisms. Identifying responsible compounds and implementing effective wastewater treatment are crucial to reduce potential environmental risks.