The Influence of Lighting Conditions on Color Difference (ΔE) in Glazed Fixed Prosthetic Restorations: A Comparative Study

Background: Achieving optimal esthetics in fixed prosthodontics requires not only accurate material selection but also precise color matching. The color difference parameter (ΔE) plays a crucial role in objectively quantifying color variation between dental restorations under different conditions. Surface finishing techniques such as glazing, as well as the lighting environment during color evaluation, may significantly affect ΔE values and thus influence clinical outcomes.
Objective: This study aimed to evaluate the effect of two lighting conditions—natural daylight and artificial reflector light—on the color difference (ΔE) values of glazed fixed prosthetic crowns fabricated from three different materials: metal-ceramic, full-contour zirconia, and veneered zirconia.
Materials and Methods: Ninety crowns (n = 30 per group) were fabricated and uniformly glazed. The specimens were divided into three groups according to the material type: Group A (metal-ceramic), Group B (full-contour zirconia), and Group C (veneered zirconia). ΔE values were recorded using a calibrated spectrophotometer under standardized daylight and reflector light conditions. The Mann-Whitney U test was used for statistical analysis to compare lighting effects within each material group.
Results: There were no significant differences in ΔE for metal-ceramic and full-contour zirconia. A significant difference was found in the veneered zirconia group (Z=-3.005; p=0.003).
Conclusion: Lighting conditions can influence the perceived color difference in glazed restorations, particularly in layered, translucent systems like veneered zirconia. These findings support the use of standardized natural lighting environments during shade selection and final evaluation of esthetic restorations to minimize metamerism and optimize color matching outcomes.
Key Word: ΔE, glazed restorations, lighting conditions, zirconia, color perception, spectrophotometry, esthetic dentistry