Accuracy and agreement of mobile applications in measuring gingival colour: a comparison with spectrophotometry

Mobile applications may offer an accessible alternative for objective gingival colour measurement; however, their accuracy compared with spectrophotometry remains unclear.

This study evaluated the accuracy and agreement between seven mobile applications and a reference spectrophotometer for gingival colour measurement using CIELAB coordinates and CIEDE2000 colour differences across different gingival regions. It also assessed whether discrepancies varied according to the region evaluated.

A SpectroShade Micro was used as the reference device. Seven applications were tested: four iOS apps using an iPhone 12 Pro Max and three Android apps using a Samsung Galaxy A52s 5G. Gingival colour was recorded in 250 participants with healthy gingiva in five regions: mesial papilla, distal papilla, free gingival margin, attached gingiva, and mucogingival line. CIELAB values were recorded in triplicate. Differences in L*, a*, b*, and ΔE₀₀ were calculated and analysed statistically.

All mobile applications showed relevant discrepancies compared with the spectrophotometer. The greatest differences were mainly observed in L*, with most applications recording higher lightness values. Android Color Picker AR and Android Colorimeter showed the largest chromatic discrepancies, particularly for a* and b*. OptiShade showed the smallest differences, although its results were still clinically unacceptable in more than 65% (n=163) of cases. Android applications exceeded 98% (n=246) unacceptable differences in all regions CONCLUSIONS: None of the evaluated applications achieved accuracy comparable to spectrophotometry for gingival colour assessment. Although OptiShade performed best, mobile applications cannot currently be considered reliable standalone tools.

These applications may be useful as complementary tools, but clinical judgement and validated dental-specific technologies remain essential.