# Level of Agreement in Subjective Selection of Gingival Colour
## 3 Results  
Table 2 shows the means and standard deviations of the colour differences--calculated using the Euclidean formula (\(\Delta\)Eab*) and the CIEDE2000 formula (\(\Delta\)E00)--between the colour coordinates of the shade tab chosen by the male observer and the patient's objective colour coordinates (recorded using the spectrophotometer). There were no statistically significant differences between the mean values of the colour differences with both formulae, in the five gingival zones (CIELAB: F = 1.972, \(p\) = 0.100; CIEDE2000: F = 0.848; \(p\) = 0.496). Table 3 shows the means and standard deviations of the differences between the colour coordinates of the shade tab chosen by the male observer and each objective colour coordinate of the patients' gingiva. There were statistically significant differences between the three coordinates in the five gingival areas. In all of these areas, the a* coordinate had the lowest level of \"fit\" between the subjective and objective readings. In contrast, the L* coordinate had the best \"fit\". Figure 4 shows the differences in each colour coordinate for the 47 patients for whom the male observer selected the shade tab he considered closest to their gingival colour, by gingival zone. Figure 4a shows the differences in the L* coordinate (lightness) between the selected shade tab and the gingiva, by gingival zone. Positive differences in L* (\(\Delta\)L*) indicate that the chosen gingival shade tab was lighter than the gingiva, while the opposite is true for negative differences in L*. As can be seen in this figure, the number of data points located above the \(\Delta\)L* = 0 line is practically the same as the number of data points located below it for the mesial and distal papilla (25 vs. 22 and 24 vs. 23, respectively); for the free gingival \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{3}{c}{**“Chromatic Errors” of the Male Operator**} \\ \hline  & **CIELAB (\(\Delta\)Eab*)** & **CIEDE2000 (\(\Delta\)E00)** \\ \hline Mesial papilla & 12.08 (5.30) & 9.48 (4.99) \\ Distal papilla & 10.29 (4.92) & 8.96 (4.95) \\ Free gingival margin & 13.12 (5.53) & 10.30 (5.09) \\ Middle zone & 11.96 (4.10) & 9.05 (3.69) \\ Mucogingival line & 11.87 (4.80) & 8.64 (5.05) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Means (standard deviations) of the colour differences between the colour coordinates of the shade tabs chosen by the male observer and the objective colour coordinates of the participants’ gingiva (\(n\) = 47). \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \(\Delta\)L* & \(\Delta\)A* & \(\Delta\)B* & \(p\) Value \\ \hline Mesial papilla & 0.79 (8.83) & 3.61 (6.32) & \(-\)3.23 (5.88) & \(<\)0.001 \\ Distal papilla & 0.98 (8.55) & 4.75 (5.53) & \(-\)2.30 (5.68) & \(<\)0.001 \\ Free gingival margin & \(-\)1.06 (9.28) & 4.59 (6.97) & \(-\)3.51 (6.02) & \(<\)0.001 \\ Middle zone & \(-\)2.37 (7.44) & 6.26 (5.43) & \(-\)3.10 (4.75) & \(<\)0.001 \\ Mucogingival line & 2.86 (7.51) & 6.60 (4.88) & \(-\)3.05 (4.94) & \(<\)0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Means (standard deviations) of the differences between each colour coordinate of the shade tab selected by the male observer and the objective colour coordinates of the patients (\(n\) = 47). margin and the middle zone, there are fewer data points above the line than below (21 vs. 26 and 18 vs. 29, respectively), indicating that the male observer selected more shade tabs that were darker than the gingiva than tabs that were lighter; finally, at the mucogingival line, the number of data points above the L* = 0 line is greater than the number below it (27 vs. 20), showing that the male observer chose more tabs that were lighter than the gingiva than tabs which were darker in that zone. However, the proportion of data points for which \(\Delta\)L* > 0 does not differ significantly in the different gingival zones (\(\chi^{2}\) = 4.257, \(p\) = 0.372).