Excretion of dental resin monomers and metabolic intermediates via urine in guinea pigs.

ABSTRACT

OBJECTIVE: Monomers like BisGMA (Bisphenol-A-glycidyldimethacrylate) and comonomers like TEGDMA (triethyleneglycoldimethacrylate) are used in dental restorative materials in order to build up the three-dimensional network of filling materials. Since earlier investigations revealed uptake and subsequent metabolism of unpolymerized remainders of (co)monomers, the present experiment investigates the metabolic urine pattern of guinea pigs (n=4) after application of TEGDMA or BisGMA (each dose=0.02 mmol/kg body weight=100%), respectively. METHODS: For the investigations BisGMA was pre-dissolved in DMSO and subsequently diluted with 0.9% NaCl solution (final DMSO concentration 1%) and TEGDMA was dissolved in 0.9% NaCl solution. The solutions were administered with a gastric tube into the animals. Control animals received either 0.9% NaCl or 0.9% NaCl solution with 1% DMSO solution. RESULTS: After 24h in collected urine the following metabolites were identified. After administration of TEGDMA (mean relative concentration of administered substances)+/-s.d. [%]; n=4) unchanged TEGDMA 12+/-1.5%, MA 2.4+/-0.8%, and triethyleneglycol 35+/-2.2%. After administration of BisGMA (mean+/-s.d. [%]; n=4) unchanged BisGMA 11.4+/-2.7%, MA 2.2+/-0.6%, and bisphenol-A-bis(2,3-dihydroxypropyl)ether 60.1+/-5.2%). CONCLUSION: No further metabolites like the previously identified intermediate 2,3-epoxymethacrylic acid and derived reaction products were identified in the urine, indicating that these metabolites must have reacted further.