# Level of Agreement in Subjective Selection of Gingival Colour
## 3 Results
As can be seen in Figure 5a, 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 (50 vs. 51 and 53 vs. 48, respectively); for the free gingival margin, there are fewer data points above the line than below (46 vs. 55), indicating that the female observer selected more shade tabs that were darker than the gingiva than tabs that were lighter in that zone; finally, for the middle zone and the mucogingival line, the number of data points above the line is greater than the number below it (62 vs. 39 and 74 vs. 27, respectively), showing that the female observer chose more tabs that were lighter than the L* coordinates provided via the spectrophotometer in these zones. For the female observer, there were significant differences in the proportion of data points for which \(\Delta\)L* > 0 in the five different gingival zones (\(\chi^{2}\) = 20.136, \(p\) < 0.001). Figure 5b-f show that, in all the gingival zones, there is a larger number of data points in the second quadrant than in the others, indicating that most of the shade tabs chosen by the female observer contained more red and less yellow than the g \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{3}{c}{**“Chromatic Errors” of the Female Operator**} \\ \hline  & **CIELAB (\(\Delta\)Eab*)** & **CIEDE2000 (\(\Delta\)E00)** \\ \hline Mesial papilla & 12.80 (5.31) & 10.22 (4.94) \\ Distal papilla & 12.05 (4.82) & 9.02 (4.55) \\ Free gingival margin & 11.88 (4.84) & 9.27 (4.20) \\ Middle zone & 11.11 (4.46) & 8.61 (4.04) \\ Mucogingival line & 12.76 (5.31) & 10.21 (5.69) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Means (standard deviations) of the colour differences between the colour coordinates of the shade tabs chosen by the female observer and the objective colour coordinates of the participants’ gingiva (\(n\) = 101). \begin{table}
\begin{tabular}{c c c c c} \hline  & \(\Delta\)L* & \(\Delta\)a* & \(\Delta\)b* & \(p\) Value \\ \hline Mesial papilla & \(-1.21\) (9.97) & 4.27 (6.75) & \(-1.52\) (5.16) & \(<\)0.001 \\ Distal papilla & 0.84 (8.20) & 5.36 (6.16) & \(-2.21\) (5.47) & \(<\)0.001 \\ Free gingival margin & \(-1.22\) (8.08) & 4.88 (5.93) & \(-3.31\) (5.38) & \(<\)0.001 \\ Middle zone & 1.02 (7.81) & 4.11 (5.37) & \(-3.11\) (5.19) & \(<\)0.001 \\ Mucogingival line & 5.44 (9.05) & 4.43 (5.83) & \(-1.42\) (4.98) & \(<\)0.001 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Means (standard deviations) of the differences between each colour coordinate of the shade tabs selected by the female observer and the objective colour coordinates of the participants (\(n\) = 101). participants. The proportion of data points in each quadrant did not differ significantly between the five gingival zones (\(\chi^{2}=12.147\), \(p=0.434\)). Table 6 shows the unweighted Kappa coefficients of agreement between the choices made by the male observer and the female observer for the 47 patients for which both made shade tab selections, with colour readings in the five gingival zones (a total of 235 objective and subjective colour readings). Except for the free gingival margin, where there was a level of alignment between their readings that was not significant, the level of agreement between the observers was low in the other gingival zones [44]. Of the 235 selections made by the male observer (47 participants \(\times\) 5 gingival areas), the most frequently chosen tabs were number 11 (77 times, 32.77%) and 12 (62 times, 26.38%). These two tabs were also those chosen most frequently in the 505 selections made by the female observer: number 11 was chosen 136 times (26.93%) and 12 was chosen 121 times (23.96%). If we consider the entire set of gingival shade tabs (\(n=21\)), there were no significant differences in the selection percentages for each shade tab between the male operator and the female operator (\(\chi^{2}=29.714\); \(p=0.056\)).