Accuracy of Tooth Color Determination Using an Intraoral Scanner: a Spectrophotometric Analysis

Objectives: This study evaluated the accuracy of an intraoral scanner in determining tooth color by comparing its results with two other color-measuring instruments and further analyzing the color differences between the tooth and selected shades using spectrophotometric parameters.
Methods: The tooth color of maxillary central incisors was assessed by trained examiners using the Trios intraoral scanner (TR, 3Shape) and two color-measuring devices: the Easyshade V (ES, VITA) and Crystaleye (CE, Olympus). Shades were categorized according to the VITA Classical Shade Guide and the bleaching shades of the 3D Master system. Agreement between methods was assessed using Cohen’s and Fleiss’ Kappa coefficients. Spectrophotometric color data from CE were analyzed to evaluate CIELAB parameters (ΔE, ΔL*, Δa*, Δb*) for the shades selected by the Trios scanner.
Results: Cohen’s Kappa showed values of 0.319 (TR vs. ES) and 0.320 (TR vs. CE), while Fleiss’ Kappa across all methods was 0.241, indicating fair agreement. The mean color difference (ΔE) between the selected shade and the actual tooth color was 3.82 ± 2.33. For non-bleached teeth, ΔE was 3.25 ± 1.68, while for bleached teeth, ΔE was higher at 5.18 ± 2.75, indicating greater difficulty in accurately matching shades. No significant differences were found in ΔL*, Δa*, or Δb* values.
Conclusions: While the intraoral scanner demonstrated fair agreement with other color-measuring instruments, the average ΔE exceeded the clinically acceptable threshold for color matching, particularly for bleached teeth. Utilizing multiple methods for tooth color determination may improve matching accuracy and enhance aesthetic outcomes.