Visual and instrumental agreement in dental shade selection: Three distinct observer populations and shade matching protocols

Objectives. This study tested the hypothesis that the agreement between observer visual dental shade matches and instrumental shade identification is higher using the Vita 3D-Master (R) (3D) shade guide than the Vita classical (VC) shade guide. Methods. Three populations selected shade matches: non-dental observers (GP) matched shade tabs-to-tabs and dental students (DS) and dentists (DD) matched an in vivo natural right upper central incisor (RUCI). All observers (n = 600) used both shade guides (3D and VC) in two lighting conditions, cool white fluorescent lighting (CWF) and natural sunlight (NSL). The shade tabs and natural teeth were identified using an intra-oral spectrophotometer (Vita Easyshade (TM)) to determine the instrumental agreement with the visual shade selection. The percent visual-instrumental shade agreement (PVIA) was analyzed statistically considering: observer population, shade guide set, and lighting condition. Results. A "substantial" intra-examiner agreement (k = 0.76) was observed. The PVIA ranged from 12% (DS) for the 3D-NSL condition to 42% (DD) with the VC-CWF condition, which also resulted in the highest PVIA for GP (38.5%) and DS (35%). Results indicated that the GP with neither dental knowledge nor shade guide experience had a significantly higher PVIA using the VC rather than the 3D shade guide. Dentists demonstrated the highest PVIA (42%) for both lighting conditions and shade guides, thereby rejecting the study hypothesis. Significance. A significantly higher visual-instrumental shade agreement was demonstrated by the clinically experienced dentists (DD), regardless of shade guides and lighting conditions. (c) 2008 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.