Agreement among tooth color measurement devices: An experimental comparison

To compare the measurement results of different instrumental color analysis methods with a reference spectrophotometer.

Six different methods (DSLR camera and smartphone camera with and without cross-polarizing filter, VITA Easyshade and Spectroshade spectrophotometers) were evaluated using four different shade tabs (1M1, 3R2.5, 3L2.5, 5M3). X-Rite MetaVue VS3200, a highly repeatable spectrophotometer, was used as the reference method. All images were captured in RAW format using standardized lighting and white balance for photographic methods and analyzed using Adobe Photoshop. Beside the L*, a*, b* values, the ΔE₀₀ values were measured. Data was analyzed using one-way ANOVA and Tukey tests (P= 0.05).

According to ANOVA test, the L*, a*, b* values of all groups showed significant differences for all shades (P< 0.05). When compared with the X-Rite MetaVue VS3200 group, the obtained ΔE₀₀ values also showed significant differences (P< 0.001) and were above the acceptability threshold. All ΔE₀₀ values were above the acceptability threshold (ΔE₀₀> 1.8) for all groups. The color measurement methods used in dental literature often produce inconsistent results when compared to each other. In this study, the results obtained from the tested methods were also inconsistent with the reference method. Therefore, the commonly used color measurement methods in dental research should be reconsidered.

Accurate tooth color determination relies on controlled lighting, geometry, and proper device calibration. This study demonstrated that variations among instrumental methods may exceed clinically acceptable limits, underscoring the importance of standardized measurement conditions. Clinicians should recognize that color analysis can differ between devices, even under identical settings, highlighting the significance of accurate color detection for optimal clinical outcomes.