A Comparison of Resin Cement Color Stability Over Six Months

Objectives: To compare the color stability over six months of five commercially available resin cements cured in different modes.

Methods: Specimens of NX3 (Kerr), Calibra (Caulk), Variolink II (Ivoclar), Rely X ARC (3M/ESPE), Multilink (Ivoclar) (clear or translucent shade, n=10) were fabricated in a cylindrical mold (8 mm diameter, 2 mm height).   NX3, Variolink II, Calibra were evaluated in light-cure only, all five were evaluated in dual- and self-cure modes.  The resin cement was expressed into the mold, a mylar strip placed on top of the mold to remove excess, and cured.  The specimen was removed, flash removed, and both sides were lightly abraded on 600 grit abrasive paper to achieve a uniform finish surface.  Two hours (+/- 20 minutes) after curing, an initial color measurement (CIE-L*a*b*) was conducted with a chromameter (Minolta).  Specimens were placed in deionized water for 24 hours and 45, 81, 114, 154 and 183 days at 37 ^oC,  after which the CIE-L*a*b* color data was repeated.  The difference in Delta E* from baseline to 183 days was calculated and statistically compared using a one-way ANOVA/Tukey's (p<0.05).

Results: Light Cure: NX3 = Calibra < Variolink

Dual Cure: NX3 = Variolink < Multilink = RelyX = Calibra

Self Cure: NX3 < Multilink = Variolink < Calibra < RelyX

Conclusion: NX3 showed the lowest color change of all tested cements in all cure modes; the color change it did demonstrate is not likely clinically significant. Study supported by Kerr Corp.