The Effect of Different pH Levels of Artificial Saliva On The Color Stability of Self-Adhesive Resin Cements

Objectives: To evaluate the effect of different pH levels of artificial saliva on the color stability of self-adhesive resin cements.
Methods: 30 disc-shaped cylinders in same shade (8mm diameter, 1mm height) were fabricated for each resin cements. (RelyX U200, G-Cem, Smart Cem 2). Specimens of each resin cement group were divided into 3 subgroups (n=10) and stored into 3 different pH levels (pH3.5, pH7, pH10) of artificial saliva for 10 days at 37°C. The color values of all groups were measured before and after exposure to artificial saliva with a spectrophotometer (Vita easyshade). Data were recorded according to the CIE L*a*b* system and then color changes (ΔE*) were calculated. Mean values were statistically analyzed using Kruskal Wallis test.
Results: There was no statistical significant difference between G-Cem and Smart Cem 2 for pH 3.5 level. In RelyX U200 for pH 3.5 and pH 7 levels, there were statistically significant differences (p<0.005). In RelyX U200 for pH 3.5 and pH 10 levels, there were statistically significant differences. In RelyX U200 for pH 7 and pH 10 levels, there were no statistically significant differences (p>0.005). For all pH levels, there were statistically significant differences. For pH 3.5 and 10 levels, there were statistically significant differences between RelyX U200 and G-Cem. Also there were statistically significant differences between Smart Cem 2 and G-Cem. There were no statistically significant differences between RelyX U200 and Smart Cem 2. For pH 7 levels, there were statistically significant differences between all groups. G-Cem had the lowest ΔE* between all groups for all pH levels. In G-Cem and Smart Cem 2, pH changes had no effects on the color stability.
Conclusions: G-Cem resin cement, which had the better color stability in different pH levels, was recommended to use in adhesive cementation.