Color adjustment potential of resin composites

Objectives: The purpose of this study was to evaluate color adjustment potential (CAP) of resin composites.

Materials and methods: Two shades of each of eight commercial resin composites and one control shade were evaluated. Visual (color competent observers, controlled conditions) and instrumental color evaluations (spectroradiometer, spectrophotometer) were performed. The data were analyzed by analysis of variance, Fisher's PLSD intervals for comparison of means, and Spearman's rank order correlation.

Results: Instrumental color adjustment potential (CAP-I) ranged from - 0.51 to 0.74, and corresponding Fisher's PLSD intervals were 0.1 and 0.05, respectively (p < 0.0001, power 1.0). Visual color adjustment potential (CAP-V) ranged from 0.10 to 0.78, and corresponding Fisher's PLSD intervals were 0.2 and 0.1, respectively (p < 0.0001, power 1.0). The greatest overall color shifting between test shades in isolation and the same shades surrounded by control shade were recorded for HRi ENA enamel, followed by Clearfil Majesty ES2. The highest visual CAP (blending) was recorded for Herculite Ultra, HRi ENA enamel, and Clearfil Majesty ES2.

Conclusion: Within the limitation of the study, it was found that color adjustment potential (CAP) was composite and shade-dependent. Positive CAP was recorded both instrumentally and visually for majority of composites and shades. Overall, the measured color difference reduction associated with positive CAP was 31%, while the average visual CAP was 43%.

Clinical relevance: Resin composites with pronounced color adjustment potential interact with surrounding dental restorations. Introduced CAP-V and CAP-I were indirect measurements of blending (optical illusion).