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Clinical RelevanceUsing the Vita 3D-Master shade guide, the accuracy of three experienced clinicians was compared to shade choices using an intraoral spectrophotometer. Compared to the clinicians, the shades chosen by the Easyshade guide were more frequently an exact match. This study indicates shade matching may be improved by using an electronic device. SUMMARYConsistently choosing an accurate shade match is far more difficult than it appears. Recently, several electronic shade-matching devices have been marketed. One device is an intraoral spectrophotometer, Easyshade. The current study compared the accuracy and consistency of the Easyshade (ES) device to three clinicians experienced in tooth whitening trials and trained in the use of the Vitapan 3D Master shade.The maxillary anteriors of 16 participants were matched on three separate occasions one month apart. At each appointment, the three clinicians (R1, R2 & R3) and ES independently chose a single 3D Master tab. A trained research assistant used the Easyshade device to record CIE L*, C* and H* and a shade tab. In addition, color differences between shade tabs were calculated using the Delta E 2000 (∆ e 00) formula. The CIE L*C*H* data were also used to establish standards for the five lightness groups of the 3D Master. An intrarater agreement was evaluated using an intraclass correlation statistic, and an inter-rater agreement was evaluated using a weighted Kappa statistic.The percentages of exact matches were: ES = 41%; R1 = 27%; R2 = 22% and R3 = 17%. Matches within a half-shade were also calculated. This represents a mismatch that is perceptible but acceptable. The percentages of matches within a half-tab were: ES = 91%; R1 = 69%; R2 = 85% and R3 = 79%. In terms of lightness, the intra-rater The mean color difference for the L*, C*, H* data recorded at each evaluation was 1.5, or only slightly greater than the color difference between the same tab on different guides (1.2). The ∆ e 00 data were the most accurate data collected, and they were used to establish a standard to which the tab choices of the four raters were compared. A weighted Kappa statistic was performed and, in terms of lightness, agreement was found to be good for all raters. For chroma, agreement was very good for ES and it was good for the clinicians.In terms of the number of exact matches and matches within a half-shade, the performance of ES was at least comparable to, if not better than, the dentists. Statistically, the same was true in terms of consistency and accuracy when making repeated matches of lightness and chroma using the 3D Master shade guide.

The results from a large group of people are more likely to include a wide cross-section of the population sampled. This data provides practitioners with a better estimate of what their patients are likely to experience. It is estimated that, during 2 weeks of active bleaching, 77% of people will experience 3 or fewer days of sensitivity. On average, sensitivity is short-lived, thus making it is easy to underestimate the importance of discussing sensitivity with patients considering bleaching. However, for some, the duration of sensitivity is much greater and has a very negative impact on satisfaction.

In order to use CAD CAM (Computer Aided Design, Computer Aided Manufacturing) technology as an assessment tool when evaluating the preclinical performance of dental students, it is imperative that one has conidence in the reliability of the process. In this study, a variety of alignment methods were compared to determine both the consistency and accuracy of each method. Although the "Tooth Dots Diagonal" method exhibited the best precision (coeficient of variation=5.4 percent), it also represented the least accurate method when compared to the other methods tested. Using "Small Dots Diagonal" on the gingiva appears to be the best option, exhibiting an acceptable coeficient of variation (17.6 percent) and a high degree of accuracy in terms of tolerance (mean±standard deviation=0.163±0.029). Based on the results of this study, further investigation of CAD CAM technology for the purpose of assessment and education of dental students is recommended.