Does Shade Guide Familiarity Improve Shade Recognition and Instrumental Agreement?

The possibility of improving one's shade recognition and matching ability is reported in the literature. Objectives: This study tested the hypothesis that there will be an increase in shade selection and instrumental agreement over one year following instruction for use (I) of the Vita 3D-Master^® (3D) shade guide. Methods: Two groups with varying experiential levels agreed to participate in 3D shade guide instructions and use. The results were recorded by a calibrated external examiner during 12 months (mo) as follows: 0_mo (baseline, no I); 0_moI (baseline after I); and at 3_mo, 6_mo, and 12_mo.  Two hundred dentists (DD) and 200 dental students (DS) matched an in-vivo natural right upper central incisor (RUCI) under both cool white fluorescent lighting (CWF) and natural sunlight (NSL). Each shade selection was identified using an intra-oral spectrophotometer (VITA Easyhade™) positioned in the middle third of the buccal surface of the RUCI. The percent visual-instrumental shade agreement (PVIA) was analyzed statistically considering lighting (NSL and CWF) and recording periods per population (DD and DS). Results: A “substantial” intra-examiner agreement (k=0.76) was observed. Gender was relatively balanced with 89 female DD, 109 male DD and 102 female DS, 96 male DS. Only four participants (2 DD and 2 DS) were unable to complete the one year study. The PVIA (%) per recording time and lighting, and the statistical groupings per population are as follows: