Surface analysis of dental composite and its polymeric overlayer model system by mass spectrometry

Dental composites consisting of resin matrix, reinforcing glass filler particles and silane coupling agents undergo material property changes during exposure to the oral environments. Characterization of dental composites includes leaching analysis of inorganic materials and resin matrix degradation analysis.; Wavelength dispersive spectroscopy and secondary ion mass spectrometry were used to analyze the Ba and Sr loss on dental composites after being aged. Differences in leaching were observed, and three mechanisms were proposed.; Degradation studies of dental composites were severely limited by their chemical complexity. A model of Bis-GMA-methacryloyl overlayer was proposed to simplify the composites and used to study degradation process. Characterization of this model was mainly performed by laser desorption postionization mass spectrometry. Postionization was performed by both 157 nm (7.9 eV) and 118 nm (10.5 eV) radiation to verify the chemistry and morphology of the model. Preliminary aging results demonstrated that 7.9 eV LDPI MS can follow the chemical processes resulting from aging in different oral environments with higher S/N and better sensitivity than 10.5 eV.