Work

Evaluating visual thresholds and color metrics in dental research: An exploratory study

Year: 2025

Type: article

Abstract: Objectives This study aimed to evaluate perceptibility (PT) and acceptability thresholds (AT) for multiple color measurement devices and assess the performance of three color difference equations (∆ E * ab , ∆ E 00 , and ∆ E 94 ) using a visual dataset from expert observers. Methods A visual dataset previously published was extended by adding the x-rite MetaVue spectrophotometer and ∆ E 94 to the analysis. Visual scaling was performed on 26 sample pairs of teeth using magnitude estimation. Observers answered PT and AT questions to determine thresholds. Threshold estimation was conducted using a model-free method, and device performance was analyzed using the standardized residual sum of squares ( STRESS) index and visual instrument agreement scale ( VIAS ). Results The PT and AT thresholds varied across devices and color difference equations. For ∆ E 00 , STRESS values ranged from 23 to 32 (mean 29, sd 2.9), with VIAS scores between 68 % and 77 % (mean 71 %, sd 2.9). ∆ E 94 showed higher STRESS values (24–42, mean 34, sd 5.5) and lower VIAS scores (58–76 %, mean 66 %, sd 5.5). ∆ E * ab demonstrated excellent visual-instrumental agreement with STRESS values from 18 to 36 (mean 24, sd 5.9) and lower VIAS scores (82–64 %, mean 76 %, sd 5.9) outperforming ∆ E 94 and ∆ E 00 . The x-rite MetaVue achieved excellent results under controlled conditions but it is unsuitable for clinical research due to its design. Significance This study highlights the variability in PT and AT across devices, suggesting the need for device-specific thresholds. It also demonstrates the effectiveness of ∆ E * ab in dental colorimetry compared to more complex color difference metrics

Source: Dental Materials

DOI: 10.1016/j.dental.2025.04.006

Authors: Sascha Hein, Michael Zangl, Tobias Graf, Kirstin Vach, Jan-Frederik Güth, Stephen Westland