Does a Purple Silicone Guide Can Be Used for Standardization of Tooth Color Evaluation? A Clinical Trial

This clinical trial aimed to evaluate the influence of a purple repositioning silicone guide on color assessment before and after at-home tooth bleaching.

Forty-five individuals received 10% carbamide peroxide at-home tooth bleaching using custom trays on both arches, 3 h per day for 2 weeks. Upper canines were evaluated with a spectrophotometer in two different ways: with and without (control) a purple silicone guide. Tooth color was assessed using the CIELab (ΔE* _ab ), CIEDE2000 (ΔE ₀₀), and the whitening index for dentistry (ΔWI _D ) at baseline, 2 and 4 weeks after the beginning of treatment. Data were analyzed using paired t tests for dependent samples (p < 0.05).

At all evaluation periods, the use of the purple silicone guide resulted in lower b* values and higher WI _D values (p < 0.001) compared with the control group. At 2 and 4 weeks, the repositioning guide resulted in lighter teeth (higher values of ΔE* _ab , ΔE ₀₀, and ΔWI _D ) than the group that did not use the guide (p < 0.04).

The use of a purple repositioning guide with a spectrophotometer influenced the color measurement of upper canines before and after at-home tooth bleaching.