Shade variability and stability in interim and definitive tooth‐colored resin‐based restorative materials: Comparing manufacturer‐claimed shades to a universal shade guide

• Published in: Journal of prosthodontics
• Main Authors: Alfaraj, Amal, Nagai, Toshiki, Lin, Wei‐Shao
• Format: Journal Article
• Language: English
• Published: United States 12.05.2025
• Subjects: shade guide; CAD‐CAM; shade matching; Delta E; esthetics
• ISSN: 1059-941X; 1532-849X; 1532-849X
• DOI: 10.1111/jopr.14069

To evaluate the shade variability and stability of interim and definitive tooth-colored restorative materials by comparing manufacturer-claimed shades to a universal shade guide before and after thermocycling. Eight commercially available tooth-colored restorative materials were tested, including conventional, milled, and 3D-printed types. Each material was categorized into three shade subgroups (A1, A2, and A3), with 10 samples per subgroup. The color differences (ΔE ) between the materials' shades and a universal shade guide (VITA classical A1-D4) were measured using a digital spectrophotometer before (ΔE ) and after (ΔE ) thermocycling. A higher ΔE indicated higher variability between the manufacturer-claimed shade and a corresponding universal shade guide. The ΔE was analyzed using the CIEDE2000 formula, and statistical analysis was performed to evaluate the effects of materials, shades, and thermocycling. In addition, the ΔE was compared against 50%:50% perceptibility threshold (PT) and 50%:50% acceptability threshold (AT) using one-sample t-tests (α = 0.05). The observations from descriptive statistics showed that the milled Aidite group exhibited the lowest ΔE . In addition, shade A1 showed higher ΔE than A2 and A3 within each group; however, the ΔE between shade types A2 and A3 was similar. The three-way interaction among materials, shades, and thermocycling was significant (p < 0.0001), highlighting their combined effect on ΔE . No significant interaction between shade and thermocycling was observed (p = 0.6239), suggesting that thermocycling did not significantly affect ΔE among shade subgroups. Comparison of ΔE and ΔE against 50%:50% PT (0.8) and 50%:50% AT (1.8) revealed significant color differences beyond both thresholds for most study groups. Color variability in dental restorative materials is influenced by material, shade, and thermocycling. Most samples showed significant discrepancies from manufacturer-specified shades (A1, A2, and A3) when compared to the VITA classical A1-D4 guide. Clinicians might consider using a custom shade guide that is fabricated from the same material as the prostheses to improve shade matching outcomes.