Reproducibility and comparison between methods for gingival color evaluation: a validation study

ABSTRACT

Aim This study aims to evaluate and validate the sensibility and the level of agreement between different gingival color measures obtained by a spectrophotometer (SPECTRO) and a photography (PHOTO) method. Methods Among 40 patients, the color was measured 2 mm apical to the gingival margin by CIE L*, a*, b* system using a reflectance spectrophotometer and the photography's plus software. The level of agreement between three different measures (m1, m2, m3) in parameters L*, a*, b*, and ∆E (color variation) was evaluated by random and systematic errors, as well as the limits and coefficient of concordance. A comparison between the methods was performed by the Bland-Altman test and the sensibility level was evaluated accordingly to the ∆E 3.7 thresholds with p<0.05 as the level of significance for these comparisons. Results The SPECTRO method has not presented the systematic error (p>0.05) and had reproducibly and agreement level in three variable measures L* (r 0.6), a* (r 0.3), and b* (r 0.5) as to the PHOTO method L* (r 0.6), a* (r 0.5), and b* (r 0.5), which presented systematic error in L* values (p<0.05). The means of ∆E between measurements were 6.5 SPECTRO and 5.9 PHOTO. There was no good level of sensitivity ∆E> 3.7 and agreement between the methods, mainly for the a* values. On the other hand, for the L* and in for the most comparisons of b* values, the level of agreement was higher. Conclusion Both methods could quantify the gingival color from the coordinates L *, a *, and b *, which has shown greater reliability between the measurements acquired by the SPECTRO method.