Discoloration of Vita Classical Shade Guide by Glutaraldehyde Disinfectant

Background and Aim: Shade guide discoloration after disinfection can interfere with the appropriate color selection for dental restorations. Since one of the most important issues for patients is the color of the final restoration, the discoloration of shade guides due to disinfectants will be important. Infection control is a definite and important matter in dentistry. Due to the contradictory results of studies on the effect of disinfectants on shade guide discoloration, this study aimed to examine the discoloration of the Vita classical shade guide by glutaraldehyde disinfectant.  Materials and Methods: In this experimental study, samples of A4, B4, C4, and D4 colors were selected from the Vitapan classical shade guide, 10 pieces each (40 samples in total). Three samples of each color were immersed in distilled water as a control while the other seven were immersed in a 2% glutaraldehyde disinfectant solution. The shade pilot spectrophotometer was used for colorimetry, which was performed at baseline and 24, 48, and 72 hours after the immersion. The color of the samples was evaluated based on the CIE Lab system. The data were analyzed with two-way analysis of variance (ANOVA) and Tukeychr('39')s test. Results: The rate of color change (ΔE) of the samples was higher in the glutaraldehyde group than in distilled water (P<0.05). In addition, color change in both groups showed a significant difference at different times (P<0.05). Conclusion: The Vitapan classical color samples discolor by immersion in 2% glutaraldehyde disinfectant after 24, 48, and 72 hours, but this color change is not clinically detectable (ΔE<1).