IADR Abstract Archives
Chemical Analysis of Resin Monomer TEGDMA Stored in Aqueous Environment
Objectives: Triethylene glycol dimethacrylate (TEGDMA) is the major monomer released from dental composite resins and it leaches at levels to have toxic effects on monolayer cell cultures of oral epithelial cells. The aim of this study was to assess the long-term stability and composition changes of TEGDMA stored in aqueous media using liquid chromatography–mass spectrometry (LC-MS).
Methods: C18 reversed phase chromatography column (Sigma Aldrich, UK) with flow speed of 1 mL/min, 150 µL injection volume and 15-minute run time was used. A TEGDMA sample was diluted in 65% gradient grade acetonitrile and 35% ultra-high quality water and run through the LC-MS column. TEGDMA in freshly prepared water and TEGDMA in water that had been stored for 4 months were run for comparison. Run was isocratic, using 65% gradient grade acetonitrile and 35% ultra-high quality water as the mobile phase.
Results: Comparing the spectra obtained from the LC-MS, there was an obvious difference between the stored sample and the fresh sample with the presence of approximately 4 times as much of m/z 241 in the stored sample as opposed to the fresh sample, indicating the presence of a breakdown product of TEGDMA. The presence of m/z 241 was re-confirmed by direct injection (without the LC column) into the mass spectrometer.
Conclusions: The results of LC-MS analysis indicate that the monomer TEGDMA can break into smaller molecules after long-term storage in aqueous media. This is a particularly important discovery that has not been previously reported. This data can have significant implications in long-term oral biocompatibility studies of resin-based dental materials and also provides a better understanding of the fate of such materials when released into the environment.
Methods: C18 reversed phase chromatography column (Sigma Aldrich, UK) with flow speed of 1 mL/min, 150 µL injection volume and 15-minute run time was used. A TEGDMA sample was diluted in 65% gradient grade acetonitrile and 35% ultra-high quality water and run through the LC-MS column. TEGDMA in freshly prepared water and TEGDMA in water that had been stored for 4 months were run for comparison. Run was isocratic, using 65% gradient grade acetonitrile and 35% ultra-high quality water as the mobile phase.
Results: Comparing the spectra obtained from the LC-MS, there was an obvious difference between the stored sample and the fresh sample with the presence of approximately 4 times as much of m/z 241 in the stored sample as opposed to the fresh sample, indicating the presence of a breakdown product of TEGDMA. The presence of m/z 241 was re-confirmed by direct injection (without the LC column) into the mass spectrometer.
Conclusions: The results of LC-MS analysis indicate that the monomer TEGDMA can break into smaller molecules after long-term storage in aqueous media. This is a particularly important discovery that has not been previously reported. This data can have significant implications in long-term oral biocompatibility studies of resin-based dental materials and also provides a better understanding of the fate of such materials when released into the environment.