Objective: To determine chromameter CIELAB measurements of Vitapan Classical shade guide and compare their value-based ranking. Methods: A new set of Vitapan Classical shade guide was measured for L*, a* and b* values using a Minolta CR-321 Chroma Meter by two investigators independently. The aperture (Ø 3mm) of the chromameter measuring head was positioned at the center of each shade tab, and three measurements were made with repositioning the aperture for each measurement. Differences (Delta L*a*b*) among shades were determined, and means and standard deviations were calculated for L*a*b*, delta L*a*b* and delta E. The intra- and inter-investigator consistency of the measurements was examined using the Kruskal-Wallis One-Way Analysis of Variance on Ranks and Mann-Whitney Rank Sum Test, respectively. Spearman Rank Order Correlation test was used to examine the relationship between the numerical Vitapan shade score and the corresponding L*, a* and b* values. Results: There were no significant differences among the intra- and inter-investigator measurements (p>0.955). While the correlations between the chromameter measurements and the value-based Vitapan shade ranking were significant (p<0.05), only two L* and one a* values matched the value-based Vitapan shade ranking; none of the b* values ranked the same as the Vitapan Classical. Compared to the Vitapan Classical, deviations of the L* values varied from 1 to 7 rankings. The delta Es for one-shade differences ranged from 1.97 to 4.88, and those for two-shade differences were between 0.92 and 6.65. Conclusions: The chromameter detects a general trend of whiteness that parallels to the value-based Vitapan Classical ranking. However, significant deviations in ranking exist between the chromameter and value-based Vitapan Classical ranking. The results support the conclusion that chromameter data can only be used as a supplemental parameter for evaluating clinical efficacy of tooth whitening systems.

Back to the Prosthodontics Research Program
Back to the IADR/AADR/CADR 82nd General Session (March 10-13, 2004)

Top Level Search