IADR Abstract Archives
Influence of Observation Time on Visual Shade-Matching
Objectives: The aim of the study was to assess whether observation time influences the accuracy of visual shade-matching process in laboratory settings.
Methods: 18 observers (normal color vision and average or high color discrimination competency) participated in the study. The observers had to match the color of three ceramic tabs (A1, B4, and C2 tabs of a VITA Classical shade guide) with the tabs of another identical VITA Classical shade guide, in two different sessions (T1, T2). The observation time was recorded for each participant (sec). The three test tabs were masked so the observers did not see the original designations of the tabs during shade-matching. The color differences between the test tabs and the selected tabs were calculated using color difference formula (ΔE*00). Data were analyzed statistically (Wilcoxon Signed Rank test, significance level α=0.05).
Results: The observation time was different for the three shade tabs matched in the study, the longest time being recorded for B4 tab, in both sessions (average time/observer: T1_B4=65sec and T2_B4=68.38sec). Recorded times for C2 and A1 tabs were shorter (T1_C2=63sec, T2_C2=62.83sec and T1_A1=53sec, T2_A1=50.44sec respectively). The greatest color difference was calculated for B4 (ΣΔE*T1_B4=18.58, ΣΔE*T2_B4=12.66), while for A1 and C2 smaller color differences were calculated between test and selected shade tabs (ΣΔE*T1_C2=4.62, ΣΔE*T2_C2=1.71 and ΣΔE*T1_A1=5.49, ΣΔE*T2_A1=2.19 respectively). However, no significant difference was observed in shade-matching times between the two sessions. Furthermore, the colour differences calculated between the selected tabs and the matching tabs were not significantly different among the sessions.
Conclusions: The observation time did not vary significantly between the two shade-matching sessions. Still, the more chromatic and darker shade tab (B4) necessitated a longer observation time, being also the most difficult to match. A1 and C2 tabs were more accurately matched and required a shorter observation time.
Methods: 18 observers (normal color vision and average or high color discrimination competency) participated in the study. The observers had to match the color of three ceramic tabs (A1, B4, and C2 tabs of a VITA Classical shade guide) with the tabs of another identical VITA Classical shade guide, in two different sessions (T1, T2). The observation time was recorded for each participant (sec). The three test tabs were masked so the observers did not see the original designations of the tabs during shade-matching. The color differences between the test tabs and the selected tabs were calculated using color difference formula (ΔE*00). Data were analyzed statistically (Wilcoxon Signed Rank test, significance level α=0.05).
Results: The observation time was different for the three shade tabs matched in the study, the longest time being recorded for B4 tab, in both sessions (average time/observer: T1_B4=65sec and T2_B4=68.38sec). Recorded times for C2 and A1 tabs were shorter (T1_C2=63sec, T2_C2=62.83sec and T1_A1=53sec, T2_A1=50.44sec respectively). The greatest color difference was calculated for B4 (ΣΔE*T1_B4=18.58, ΣΔE*T2_B4=12.66), while for A1 and C2 smaller color differences were calculated between test and selected shade tabs (ΣΔE*T1_C2=4.62, ΣΔE*T2_C2=1.71 and ΣΔE*T1_A1=5.49, ΣΔE*T2_A1=2.19 respectively). However, no significant difference was observed in shade-matching times between the two sessions. Furthermore, the colour differences calculated between the selected tabs and the matching tabs were not significantly different among the sessions.
Conclusions: The observation time did not vary significantly between the two shade-matching sessions. Still, the more chromatic and darker shade tab (B4) necessitated a longer observation time, being also the most difficult to match. A1 and C2 tabs were more accurately matched and required a shorter observation time.