Use of a Silicone Mask Improves the Reproducibility of Tooth Color Assessment for Whitening Clinical Trials

<b>Objective:</b> This study aimed to investigate the reproducibility of tooth color assessment by dentists using two different spectrophotometers, Rayplicker and Vita Easyshade Advance 4.0, with or without a silicone mask developed to place its tip in the same position. <b>Methods:</b> Twenty subjects participated in this cross-over study. Multiple color coordinates and correlated whitening index measurements were performed to compare the variability with Vita Easyshade, with or without the mask, or the Rayplicker. The intrasubject variability was evaluated in consecutive measures and over time. <b>Results:</b> In consecutive measures, each subject's variance and the percentage of the coefficient of variation (CV) were minimal for each score. Bartlett's test resulted in a more significant variance for Vita Easyshade with a mask compared with either Vita Easyshade without a mask or Rayplicker. The comparison of the values obtained before and after 2'30" indicated complete reproducibility in variance and %CV data. <i>p</i> Values associated with the Bartlett test resulted in >0.90 for all the pre-post score comparisons, and no difference in pre-post %CV values was detected. Bartlett's test indicated that the measures with Vita Easyshade without the mask had significantly greater CV for <i>L</i> and <i>b</i> scores than those obtained with the mask or Rayplicker, which were similar among them. <b>Conclusion:</b> This study indicates that the silicone mask improves the precision of Vita Easyshade, and Rayplicker can be a valid alternative for studies measuring the changes in tooth color after whitening treatments.