Evaluation of Newly Developed Visual Shade Matching Apparatus

Objectives: It is generally considered that shade matching should be done in the daylight. However, daylight constantly changes. An apparatus named "Shademat Visual+" (SV+), which should render optically "ideal" conditions for visual shade matching, has been constructed and its influence on shade matching quality has been investigated. Methods: A group of 129 color normal evaluators, dental students and general dentists, matched the shade of 4 porcelain-fused-to-metal teeth. They were positioned onto the upper member of the artificial head and fastened to the head-rest of the dental chair or SV+. The Vitapan "Classical" shade guide, with the shade tabs arranged according to manufacturers' suggestion (MA), was used for shade matching. Shade matching was also performed with the tabs arranged according to total color difference in relation to the "lightest" tab, including group division (the alternative arrangement - AA). The evaluators matched the shade of artificial teeth both in the daylight (DL) and using the SV+ (artificial light - AL). The color coordinates were determined using digital image analysis. Based on DE* values, each shade matching result was ranked from 1 (the worst match) to 16 (the best match) points. Results: The evaluators achieved better result in AL trials than in DL trials - 13.2±1.1 vs. 12.4±1.2 points (p<.001). Compared to DL, 63.6% of evaluators improved their result, 9.3% showed no difference, while 27.1% achieved worse result in AL. The mean increase in points in AL minus DL trials for the entire group was 4.2. For the same PFM specimen 12.7±2.6 points were recorded with the MA and 13.7±2.5 with the AA (p<.001). Corresponding values for the SM+ trials were 13.6±2.4 and 14.6±1.6 points, respectively (p<.001). Conclusions: SV+ was better than DL for clinical shade matching. Shade tabs should be arranged according to AA.