IADR Abstract Archives
Elution of Resin-based Composite Monomers into Groundwater
Objectives: To assess the environmental pollutant risk of resin-based composite (RBC) after interment of cadavers containing restorations via an in vitro analysis of elution of monomers into groundwater.
Methods: Ceramic (lithium disilicate) teeth with uniform mesio-occluso-distal cavities were fabricated and restored, in accordance with recommended guidelines, with known volumes of two RBCs (CompA or CompB). CompA was a commercially available RBC and CompB a custom-made control standard; both containing all the monomers of interest in known amounts. The restored teeth were aged for 6 months in artificial saliva at 35°C to simulate the oral environment. Aged, restored models were placed in microcosms (in duplicates) containing groundwater at 10°C for 12 months. Sampling and analysis of groundwater was carried out at 5 intervals (t0, months 1, 5, 10, 12). Eluted monomers triethylene glycol dimethylacrylate (TEGDMA), urethane dimethacrylate (UDMA), bisphenol-A glycidyl methacrylate (Bis-GMA), hydroxyethyl methacrylate (HEMA), bisphenol-A (BPA) were quantified via solid phase micro-extraction coupled with high-performance liquid chromatography.
Results: Elution of all monomers was detected for CompA and CompB over the sampling period. TEGDMA eluted in the highest concentration for both composite materials. The ranking (greatest to least) of detected monomer concentrations was consistent between CompA and CompB (TEGDMA>HEMA>BPA>UDMA>BisGMA). The smaller molecular weight monomers (BPA, TEGDMA and HEMA) were detected in higher concentrations than the larger weight monomers (UDMA and BisGMA).
Average concentrations of monomers released over the sampling period for CompA were: TEGDMA 790mg/L, HEMA 48mg/L, BPA 45mg/L, UDMA 12mg/L and BisGMA 8mg/L. For Comp A, increased concentration over time for BisGMA correlated with a subsequent increase in BPA concentrations being detected.
Conclusions: Low concentrations of monomers from RBCs are released into groundwater over a prolonged time. The high number of restorations placed worldwide suggests a greater cumulative effect.
Methods: Ceramic (lithium disilicate) teeth with uniform mesio-occluso-distal cavities were fabricated and restored, in accordance with recommended guidelines, with known volumes of two RBCs (CompA or CompB). CompA was a commercially available RBC and CompB a custom-made control standard; both containing all the monomers of interest in known amounts. The restored teeth were aged for 6 months in artificial saliva at 35°C to simulate the oral environment. Aged, restored models were placed in microcosms (in duplicates) containing groundwater at 10°C for 12 months. Sampling and analysis of groundwater was carried out at 5 intervals (t0, months 1, 5, 10, 12). Eluted monomers triethylene glycol dimethylacrylate (TEGDMA), urethane dimethacrylate (UDMA), bisphenol-A glycidyl methacrylate (Bis-GMA), hydroxyethyl methacrylate (HEMA), bisphenol-A (BPA) were quantified via solid phase micro-extraction coupled with high-performance liquid chromatography.
Results: Elution of all monomers was detected for CompA and CompB over the sampling period. TEGDMA eluted in the highest concentration for both composite materials. The ranking (greatest to least) of detected monomer concentrations was consistent between CompA and CompB (TEGDMA>HEMA>BPA>UDMA>BisGMA). The smaller molecular weight monomers (BPA, TEGDMA and HEMA) were detected in higher concentrations than the larger weight monomers (UDMA and BisGMA).
Average concentrations of monomers released over the sampling period for CompA were: TEGDMA 790mg/L, HEMA 48mg/L, BPA 45mg/L, UDMA 12mg/L and BisGMA 8mg/L. For Comp A, increased concentration over time for BisGMA correlated with a subsequent increase in BPA concentrations being detected.
Conclusions: Low concentrations of monomers from RBCs are released into groundwater over a prolonged time. The high number of restorations placed worldwide suggests a greater cumulative effect.