Hazard assessment of resin-based dental monomers: directions for greener dental material development

The increasing use of resin-based dental materials has prompted questions about their environmental footprint. During clinical procedures, small amounts of unpolymerized monomers may enter wastewater systems, and their possible effects on aquatic invertebrates remain insufficiently explored. We hypothesized that commonly used resin-based dental monomers could exert developmental and cellular effects in an aquatic invertebrate model.

The acute and sublethal effects of five monomers associated with dental composites, namely - BPA (bisphenol A), Bis-DMA (bisphenol A dimethacrylate), Bis-GMA (bisphenol A-glycidyl methacrylate), Bis-EMA (bisphenol A ethoxylate dimethacrylate), and TEG-DMA (triethylene glycol dimethacrylate) - were evaluated in Artemia salina at both cyst and naupliar stages. The effects on naupliar survival, body length, and Lactate dehydrogenase (LDH) activity were measured to assess compound-specific biological responses.

Bis-GMA, Bis-DMA, and BPA significantly reduced survival, while Bis-EMA caused modest mortality, and TEG-DMA had no effect. Despite these differences in survival, most monomers affected naupliar growth, with greater developmental sensitivity observed following cyst-stage exposure. However, growth responses were compound specific and not uniformly dose-dependent across all monomers. LDH responses were monomer specific: Bis-GMA and Bis-DMA increased LDH activity, although Bis-DMA showed no consistent effect on growth, whereas BPA and TEG-DMA showed reductions in LDH activity, despite observed growth inhibition, and Bis-EMA showed no significant change.

Taken together, our findings show that dental resin monomers differ in their developmental and metabolic impacts, highlighting the importance of considering safety alongside clinical performance when designing and selecting dental biomaterials. As the concentrations used were for hazard screening, these results indicate possible biological effects under controlled conditions but do not necessarily reflect environmental exposure scenarios or ecological risk. Additional studies at environmentally relevant exposure levels are needed to better evaluate ecological safety and support the development of more sustainable dental materials.