The environmental impacts of dental resin-based composite

Resin-based composite (RBC) is used extensively in dentistry to restore teeth and improve oral health. This usage has negative environmental impacts via pollution, plastic waste and carbon emissions. RBC consists of an inorganic filler phase within an organic polymeric resin-based matrix phase which is typically methacrylate-based. The methacrylate monomers within RBC do not fully polymerise in normal clinical use and long-term elution results in the release of monomers into the environment via several pollution pathways. The varying typical constituent RBC monomers and degradation products are recognised to be cytotoxic, mutagenic and in the case of bisphenol-A (BPA), estrogenic. Monomers and BPA elute from RBCs in situ into sewerage as excreted human waste, from microparticulate waste into municipal wastewater when RBCs are removed, finished or polished, as disposed CAD/CAM waste microparticles into municipal wastewater, into landfill leachate or the air when RBC is disposed to landfill or incinerated, and finally into groundwater or the air when cadavers with RBC in situ are interred or cremated respectively. This study sought to investigate these pollution pathways to better understand the environmental impact of RBC. Several different analytical techniques were utilised to detect and quantify monomeric elution and characterise RBC microparticulate waste. Other aspects of environmentally sustainable use of RBC were also considered and investigated using life-cycle analysis methods and comprehensive scoping reviews of sustainable oral healthcare. Conclusions derived from this research are, monomers can be detected and quantified in the pollution pathways investigated, the full extent of the impact of pollution from RBC requires further investigation, environmentally sustainable use of RBC and other dental materials requires a reductionist approach prioritising prevention of disease and optimal clinical use to reduce the need for replacement, and coordination of all stakeholders (manufacturers, distributors, users and disposal services) within the oral healthcare supply-chain is required.