Objective: To investigate the physical and chemical changes of five esthetic restorative materials in an artificial saliva using Fourier transform infrared spectroscopy (FTIR).
Methods: The materials included two glass polyalkenoate (ionomer) cements, one polyacid-modified resin composite, and two resin composites. Five fresh and 20 aged specimens for each material were immersed in 2 ml of artificial saliva at 37 degrees C for 1 week, 2 weeks, 1 month, and 2 months. They were examined by laser surface profilometer and FTIR.
Results: Surface roughness average (Ra) value showed significant differences among the physical properties of glass ionomers, polyacid-modified resin composite, and resin composites.
Significance: FTIR spectra showed that a major chemical changes in Fuji IX GP Fast glass ionomer cement in P-NH2 group bonding (900-1000 cm(-1)) that may explain the previously reported increase in microhardness after immersion. There was no direct correlation between surface roughness and spectral changes of the materials tested.