Effect of Tooth Bleaching on The Color Change of Laminate Veneer Restorations: A Pilot Study

Objective: This pilot study aimed to evaluate the effect of tooth bleaching on the long-term color change of laminate veneers restored with different translucency CAD/CAM materials. Methods: In this study, 20 upper central teeth extracted due to periodontal, orthodontic problems and trauma were used. The teeth were embedded in acrylic blocks and divided into 4 groups of 5 teeth each. Groups A and B were bleached with a vital bleaching agent for two 20-minute sessions before preparation and teeth were prepared for laminate veneer restoration following bleaching. Groups C and D were prepared without bleaching treatment. Groups A and C were restored with high translucent A1 IPS Emax CAD material and Groups B and D were restored with low translucent A1 IPS Emax CAD material. For all restorations adhesive cementation was applied and aged for 2 years by thermal cycling. The color of the restorations was measured using a spectrophotometer after cementation and the measurement was done again after 2 years aging. The Kruskal Wallis test was used to compare data and multiple comparisons were tested with Dunn’s test. Results: The translucency of the blocks and tooth bleaching caused a significant difference between the groups according to the Kruskal Wallis test. Color changes (ΔE00) of Group A, B, C and D was 0.89±0.01, 0.87±0.01, 0.81±0.01, 0.8±0.01 respectively. Conclusion: Tooth bleaching causes a greater color change in laminate veneer restorations and the translucency of the material affects the color change of the laminate veneer restorations after aging.