Effect of curing mode of resin composite cements on water sorption, color stability, and biaxial flexural strength

Objectives

To determine whether water sorption and solubility of a recently introduced self-adhesive cement is comparable to two clinically tested resin composite cements after thermal aging, and if this is affected by the curing mode. Whether water sorption is correlated with color difference and biaxial flexural strength was also investigated.

Methods

Water sorption and solubility of three resin composite cements {RelyX Universal (RUV), (Panavia V5 (PV5), Panavia SA plus (PSA)} were measured after thermal aging. Disk-shaped specimens were either light-cured or autopolymerized (n = 15 per group). Color difference ΔE₀₀ and biaxial flexural strength were also obtained.

Results

Sorption was highest for RUV (auto: 54.9 ± 9.0 µg/mm³, light: 49.7 ± 4.9 µg/mm³), followed by PSA (auto: 37.7 ± 1.4 µg/mm³, light: 34.5 ± 1.1 µg/mm³) and PV5 (auto: 21.7 ± 0.7 µg/mm³, light: 22.1 ± 0.4 µg/mm³). Light-curing reduced solubility values, particularly for RUV (from 60.7 ± 20.8 µg/mm³ to 6.4 ± 0.8 µg/mm³). Color differences of ΔE₀₀ > 1.8 (considered clinically not acceptable) were noted after aging for RUV and PSA. Sorption and ΔE₀₀ values after aging were correlated linearly (R² = 0.970). Biaxial flexural strength values were highest for PV5 (light: 153.4 ± 15.9 MPa; auto: 133.2 ± 18.0 MPa) and lowest for RUV (light: 99.3 ± 12.8 MPa; auto: 35.1 ± 8.3 MPa).

Significance

Light-curing has beneficial effects on sorption, color stability, and biaxial flexural strength of resin composite cements. Cements containing 2-hydroxymethacrylate such as RUV and PSA are more prone to water sorption and color changes.