Repeatability of different mobile phone applications for color measurement in dentistry

To assess the repeatability of various color-measuring mobile phone applications (MPAs) on dental materials in clinically relevant shades in 1-mm thickness.

A benchtop spectrophotometer was used as a reference instrument. Seven MPAs were used: Color Analysis, Color Analyzer-Iro Shirabe, Color Grab, and Colorimeter from Android, and Color Analyzer-Iro Shirabe, ColorMeter RGB, and Optishade from iOS. Color measurements were performed on 1-mm thickness slices of CAD-CAM materials, Vita Enamic shades 1M2, 2M2, 3M2, 4M2, and Vitablocs Mark II shades A1C, A2C, A3C, A4C (n = 10, for a total 80 specimens). The specimens were measured at three time periods, Day 0, Day 1, and Day 7, and three measurements were made on each day, to mimic short-, medium-, and long-term repeatability. The color differences were analyzed using the CIEDE2000 formula, with the corresponding color difference (ΔE₀₀), and mean color difference from the mean (MCDM₀₀). One-way ANOVA, Repeated measures ANOVA, and Paired sample t-tests were used for statistical analysis.

Optishade from iOS showed the lowest mean color difference among the MPAs (ΔE₀₀ = 0.2 (SD 0.1), 0.3 (SD 0.2), and 0.2 (SD 0.1) at Day 0, 1, and 7, respectively, and ΔE₀₀ = 0.5 (SD 0.3) for all three periods Days 0-1, 0-7, and 1-7). Material-dependent variations in the repeatability of color measurements were observed.

There was a statistically significant difference among color measurements using MPAs and a spectrophotometer, among the MPAs, and materials. The spectrophotometer exhibited the highest repeatability across the tested time periods. The iOS Optishade showed the highest repeatability among the MPAs.