New shade guide for tooth whitening monitoring: visual assessment

STATEMENT OF PROBLEM: Shade guides currently used to monitor tooth bleaching lack logical order, uniform color distribution, and light shade tabs, thus, limiting the design of bleaching studies and diminishing the validity of obtained results. PURPOSE: The purpose of this study was to perform a visual evaluation of a new shade guide designed primarily for monitoring tooth whitening and to compare this shade guide with 2 commercial shade guides. MATERIAL AND METHODS: Tab arrangement of 3 shade guides (prototype of new VITA Bleachedguide 3D-Master (BG), value scale of Vitapan Classical (VC), and color-ordered Trubyte Bioform porcelain shade guide (TB)) was evaluated. The tabs from each shade guide, one at a time, were scattered and visually reordered from the lightest to the darkest by 15 observers under controlled conditions of a viewing booth. Visual ranking was compared to manufacturer-suggested ranking. Interobserver repeatability was compared using the Mann-Whitney U test (alpha=.05). All observers responded to a questionnaire grading the 3 shade guides using a Likert scale (1, strongly disagree, to 5, strongly agree). The Kolmogorov-Smirnov z-test (alpha=.05) was used to process the results obtained in the questionnaire RESULTS: Visually determined BG order was found to be identical to the order given by the manufacturer. This was not the case with the 2 other products: visual and manufacturers' order were identical for 7 of 16 VC tabs and 9 of 24 TB tabs. Interobserver repeatability for BG was significantly higher (P<.001) as compared to corresponding values recorded for VC and TB, whereas no statistically significant difference in interobserver repeatability between VC and TB was observed. CONCLUSIONS: Visually determined lightest to darkest order was identical to the suggested manufacturer order only for VITA Bleachedguide 3D-Master. The same shade guide was also superior based on the scores given in the questionnaire. These findings support the use of the new VITA Bleachedguide 3D-Master for monitoring tooth whitening.