Abstract: Objective: To compare the water absorption values, solubility values and monomer release amounts of six kinds of light curing composite resins and explore the influencing factors, and to elucidate their relationships with the material compositions and the immersing solvent. Methods: The water absorption and solubility values of six kinds of composite resins, including FiltekTM Z250(Z250), FiltekTM Z350 XT(Z350), Aelite LS Posterior (ALS), CLEARFIL MAJESTY Posterior(CMP), Neofil Nano(NN), and Tetric N-Ceram (TNC), were measured according to ISO 4049-2009. The concentrations of eluted Bis-GMA and TEGDMA were tested by liquid chromatography/mass spectrometry after the specimens were immersed in 75% ethanol solution for different time (24h, 7 d, 1 month, and 3 months). Results: The water absorption values of six kinds of composite resins were in ascending order of ALS < CMP < TNC ≈Z250 < NN < Z350,there were significant differences between groups(P<0.05);the solubility values were Z350 < NN≈ALS≈CMP≈Z250 P<0.05). The release amounts of Bis-GMA were increased slowly with the prolongation of time (P<0.05), while the values of ALS and CMP at 3 months were decreased (P<0.05); the descending order of Bis-GMA release amounts at 3 months was NN > TNC > Z250 > Z350 > ALS > CMP (P<0.05). The released TEGDMA was not found in NN and TNC. The release amounts of TEGDMA of the other four resins were increased slowly with the prolongation of time (P<0.05), and the release amount of CMP at 3 months was decreased (P<0.05); the order of amount at 3 months was ALS > CMP > Z250 > Z350 (P<0.05). Conclusion: The water absorption values, solubility values and monomer release amounts of different composite resins are different, and they are related to their organic matrix compositions and the immersing solvent.

Key words: light-curing composite resins, water sorption, monomer elution, water solubility, liquid chromatography/mass spectrometry