Consistency of Value Detection for Shade Matching Using Multiple Scanners

Objectives: Digital shade-matching systems allow for the selection of value, hue, chroma accurately to match the shade of the surrounding natural teeth. Significant variation exists during shade selection using different digital scanners. Among value, hue, and chroma, value is of greater significance than the exact color match. Discrepancies in shade are detected visually with perceived variation in value. The purpose of this study was to examine the trueness and repeatability of shade value using multiple digital systems as compared to spectrophotometer (SPM) as a gold standard.
Methods: VITA Toothguide 3D-MASTER^® tabs were scanned for their Value only (1M1, 2M1, 3m1, 4M1and 5M1) five times using a spectrophotometer and three different scanning systems: Trios3 Shape Scanner, Vita Easy Shade V and Prime Scan. Value was collected from the middle third of each tab. Tabs were placed on a black tray and scanned in the same room to control ambient light and temperature. Reliability analysis was performed to compare the consistency of detected values with each scanner against values detected with SPM. ICC estimates and their 95% confidence intervals were calculated using SPSS based on a mean-rating (x=5), two-way random, single measure.
Results: None of the scanned values were the same as values detected with SPM (Trios 3 ICC = 0.93, CI .84 to .97; Vita Easy Shade V ICC = 0.67, CI .38 to .84; Prime Scan ICC = 0.74, CI .48 to .88). Values detected with Trios 3 had good reliability, and values detected with Prime Scan had moderate reliability. Reliability was likely negatively impacted by small sample size.
Conclusions: Different scanners used to select proper shade value for different shade tabs produced variable results as compared to spectrophotometer which may impact patient satisfaction with the appearance of a final restoration.