The Effect of Positioning Guide Color on Shade Measurements Using a Clinical Spectrophotometer

• Published in: Brazilian dental journal 2024, Vol.35
• Main Authors: Dumke, Joao Arthur, Fantine, Lauren Arrua, Nogueira, Suzana, Gaidarji, Bruna, Righes, Danielle Zorzo, Rocha, Bibiana Gabardo Perez Mariano da, Durand, Leticia Brandao
• Format: Article
• Language: English
• ISSN: 0103-6440; 1806-4760
• DOI: 10.1590/0103-6440202405995

Abstract The purpose of this study was to investigate the influence of the color of positioning guides on the CIEL*a*b* color coordinates of ceramic, resin composite and bovine tooth surfaces measured by a clinical spectrophotometer. Positioning guides (n=10) in different colors (translucent, purple, yellow, green and, blue) were made for each surface (ceramic, resin composite and bovine tooth). The CIEL*a*b* color coordinates were measured with the positioning guides and with no positioning guide (control group). The ΔL*, Δa*, Δb*, ΔE*ab, and ΔE00 were calculated between the control group and the different groups. The CIEL*a*b* color coordinates were analyzed by one-way ANOVA followed by the post-hoc Tukey test (α=0.05). Color differences were interpreted using the 50:50% perceptibility and acceptability visual thresholds. Positioning guides with different colors presented significant differences for all surfaces and color coordinates. ΔE*ab, and ΔE00 mean values for all surfaces and positioning guide colors exceeded the acceptability visual thresholds, except for the bovine tooth surface measured with the green positioning guide. The shade measurement was affected by the color of the positioning guides regardless of the surface that was evaluated. Resumo O objetivo deste estudo foi investigar a influência da cor do guia de posicionamento nas coordenadas de cor CIEL*a*b* de superfícies de cerâmica, resina composta e dentes bovinos medidas por espectrofotômetro clínico. Guias de posicionamento (n=10) com cores diferentes (translúcida, roxo, amarelo, verde e azul) foram confeccionadas para cada superfície (cerâmica, resina composta e dente bovino). As coordenadas de cor CIEL*a*b* foram medidas com as guias de posicionamento e sem guia de posicionamento (grupo controle). Os ΔL*, Δa*, Δb*, ΔE*ab e ΔE00 foram calculados entre o grupo controle e os diferentes grupos. As coordenadas de cor CIEL*a*b* foram analisadas por ANOVA unidirecional seguida pelo teste post-hoc de Tukey (α=0,05). As diferenças de cor foram interpretadas utilizando os limiares visuais de perceptibilidade e aceitabilidade de 50:50%. Guias de posicionamento com cores diferentes apresentaram diferenças significativas para todas as superfícies e coordenadas de cor. Os valores médios de ΔE*ab e ΔE00 para todas as superfícies e cores do guia de posicionamento excederam os limites de aceitabilidade visual, exceto para a superfície dentária bovina medida com o guia de posicionamento verde. A aferiç