Chameleon Effect of Universal Shade Composite Polymers in Repairing CAD/CAM Lithium Disilicate

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Restorative Dentistry

Background:

• Lithium disilicate ceramic is widely used in dental restorations.
• Achieving seamless color integration in repairs of ceramic restorations remains a clinical challenge.
• Universal-shade resin-based composites (RBCs) aim to simplify shade matching for dental applications.

Purpose of the Study:

• To evaluate the color blending efficacy of different universal-shade RBCs when used for repairing lithium disilicate ceramic.
• To compare the color match of universal-shade RBCs against a control group using the CIEDE-2000 formula.

Main Methods:

• Fifteen lithium disilicate CAD/CAM blocks were prepared with four cavities each.
• Specimens were restored with five different resin composite materials, including a control and four universal-shade RBCs (Transcend-T, Omnichroma-OC, Venus Pearl-V, Clearfil Majesty Universal-CM).
• Color differences (ΔE₀₀) were measured between the restoration and the ceramic substrate using a colorimeter and the CIEDE-2000 formula.

Main Results:

• The control group (F) exhibited significantly better color matching (ΔE₀₀ = 2.51 ± 0.64) compared to most single-shade universal RBCs.
• Transcend-T (T) showed comparable color matching to the control group (ΔE₀₀ = 2.55 ± 0.64).
• All tested universal-shade RBCs, including the control, exceeded both the perceptibility and acceptability color difference thresholds.

Conclusions:

• The color blending performance of universal-shade RBCs for lithium disilicate repair varies significantly among materials.
• While some universal-shade RBCs offer improved aesthetics, none fully met clinical perceptibility and acceptability standards in this study.
• Further development of universal-shade RBCs is needed to achieve optimal color integration in ceramic repairs.