Evaluation of the repeatability and matching accuracy between two identical intraoral spectrophotometers: and in vivo and in vitro study

PURPOSE. The purpose of this study was to evaluate the repeatability and matching accuracy between two identical intraoral spectrophotometers. MATERIALS AND METHODS. The maxillary right central incisor, canine, and mandibular left central incisor of each of 30 patients were measured using 2 identical intraoral spectrophotometers with different serial numbers (EasyShade V). The color of each shade tab from 3 shade guides (VIVA 3D-Master) was also determined with both devices. All measurements were performed by a single operator. Statistical analyses were performed to verify the repeatability, accuracy, and the differences between the devices with paired t-tests, one-way ANOVA, and intra-class correlation coefficients (ICCs) (alpha=.05). RESULTS. A high level of measurement repeatability (ICC>0.90) among L*, a*, and Lo 5 color components was observed within and between devices (P<.001). Intra-device matching agreement rates were 80.00% and 81.11%, respectively, while inter-device matching agreement rate was 51.85%. ANOVA revealed no significant different color values within each device, while paired t-test provided significant different color values between both devices. The CIEDE2000 color differences between both devices were 2.28 +/- 1.61 Delta E-00 for in-vivo readings. Regarding the clinical matching accuracy of both devices, Delta E-00 values between teeth and matching shade tabs were 3.05 +/- 1.19 and 2.86 +/- 1.02, respectively. CONCLUSION. Although two EasyShade V devices with different serial numbers show high repeatability of CIE L*, a*, and b* measurements, they could provide different color values and shade for the same tooth.