Comparison of Visual Shade Guide Results to Colorimeter Data

Objectives: Comparison of visual tooth color assessment using a shade guide to that with a colorimeter in clinical evaluation of tooth bleaching efficacy. Methods: Two professional at-home tooth bleaching systems containing 16% and 15% carbamide peroxide were used. Tooth shade or color of the six maxillary anterior teeth was assessed using Vitapan Classical Shade Guide (Bad Sackingen, Germany) and X-Rite ShadeVision (Michigan, USA). There were 30 subjects (age ranging 18 to 70) in each group of A and B and their baseline shades were 11.95(sd=2.01) and 11.44(sd=1.66), respectively. The measurements were performed at baseline and a 14-day follow up visit. Numerical conversion was used for values of shade tabs. For the X-Rite, CIELAB coordinates (L*, a*, b*) were measured and calculated for units of delta L*a*b* and E. Means and standard deviations of the shade and X-Rite values as well as their differences between the baseline and 14-day measurements were determined. The Mann-Whitney U-test was performed at the 0.05 level of significance for comparing the differences between the two methods. Results: Both bleaching methods were highly effective. After bleaching visual shade reductions were 8.08(sd=2.59) and 8.04(sd=1.61), and delta E for colorimeter were 8.22(sd=3.91) and 7.72(sd=3.47) for the group A and B, respectively. There were no statistically significant differences between groups A and B in either the changes of shade (p=0.785) or delta E (p=1.000). There were no statistically significant differences between shade and delta E value changes within the same group of A and B (p=0.484 and 0.647, respectively), as well. Conclusions: The CIELAB data generated using the X-Rite are consistent with the visual assessment using the shade guide, indicating that the use of a proper electronic instrument can provide valuable supplemental supportive data to visual assessment of tooth shade in evaluating bleaching efficacy.