Accuracy of an intraoral scanner in tooth color determination: Clinical evaluation

Background

Intraoral scanners have been increasingly used to make optical impressions of teeth and implants. TRIOS 3 is an intraoral scanner with a shade-taking function. However, whether intraoral scanners with an integrated shade-taking function can substitute colorimeters, spectrophotometers, or the visual method to reduce working time is unclear.

Aim/Hypothesis

The aim of this clinical study was to evaluate the accuracy of the measurement of tooth shade obtained with an intraoral scanner in vivo. The null hypothesis was that T3 measurements would not differ from SS measurements with regard to color determination.

Material and Methods

Shades of 120 maxillary anterior teeth were evaluated by using a SpectroShade spectrophotometer (SS) and a TRIOS 3 intraoral scanner (T3) on 20 participants. The matching of shade readings between the T3 and SS was used to estimate the accuracy of the T3. The percentage of readings when a difference between the shades obtained by both devices was visually perceptible (ΔE > 3.7) was calculated. Each of the 120 teeth were measured 5 times to assess repeatability.

Results

The accuracy of the T3 was 53.3% when the color was recorded as a Vita 3D-Master (VM) shade and 27.5% for the Vita Classical (VC) shade guide when the SS was taken as a reference. A visually perceptible color difference was found in 25% (VM) and 50.8% (VC) of situations when the shade was determined with the SS and 48.3% (VM) and 78.3% (VC) with the T3. Repeatability was 92% (VM) and 93.5% (VC) for the SS, and 90.33% (VM) and 87.17% (VC) for the T3.

Conclusion and Clinical Implications

The findings of this study revealed that the tooth color determined by the T3 does not exactly match that obtained by the SS that additional methods of measuring tooth color are recommended. The accuracy of the T3 was higher when the color was recorded as VM values rather than VC values. The Vita 3D Master shade guide should be used with the TRIOS 3 intraoral scanner and supplemented with additional methods to determine the color.