Electronic Shade-Matching Devices Differ in Accuracy Reliability and Accuracy of Four Dental Shade-Matching

Objective: To evaluate the reliability and accuracy of 4 electronic devices for determining dental shades. Methods: The 4 devices evaluated were the SpectroShade (spectrophotometer), ShadeVision (digital camera with colorimeter), VITA Easyshade (spectrophotometer), and ShadeScan (digital camera with colorimeter). All of the devices were calibrated according to manufacturer instructions. Three types of shade guides were used in the study: Vitapan Classical, Vitapan 3-D Master, and Chromascop. Each shade tab from 10 shade guides of each type was measured using all 4 electronic devices. The measurements were done under simulated clinical conditions, ie, the shade tab was placed against a gingiva-colored matrix with identical shade tabs placed on each side of it. A measurement was considered to be accurate if the device selected a shade that was identical to the shade tab measured. Accuracy was expressed as a percentage of measurements made with the device that were an exact match. To measure reliability, each shade tab from 1 of each shade guide type was measured 10 non-consecutive times by each instrument. Repeated measurements were considered to be reliable if they were similar, even if they did not match the shade tab itself. Results: Reliability percentages were 99.0 for the ShadeVision, 96.9 for the SpectroShade, 96.4 for the VITA Easyshade, and 87.4 for the ShadeScan. Accuracy percentages were 92.6 for the VITA Easyshade, 84.8 for the ShadeVision, 80.2 for the SpectroShade, and 66.8 for the ShadeScan. Conclusions: The electronic shade-matching instruments had similarly high reliability, but differed substantially in accuracy. Reviewer's Comments: The VITA Easyshade had the best combination of accuracy and reliability in this study. However, as the authors discuss, the Easyshade may have benefitted from instructions that differ from those for the other devices. The manufacturer recommends that shade measurements be repeated until 2 consecutive identical measurements are obtained. In other words, this device has more opportunities to correctly measure the target shade tab. This device also has a larger probe (5 mm) than the other devices (3 mm). This study considered only the average shade of each tab, not the shade in various regions. A larger probe would be more likely to correctly measure the average shade. (Reviewer-Edward J. Swift, Jr, DMD, MS).