Color change of vital teeth exposed to bleaching performed with and without supplementary light

The aim of this clinical study was to evaluate tooth color change after exposure to 25% hydrogen peroxide in-office tooth whitening system, with and without supplementary light exposure.

Twenty subjects were treated with two separate 45-min exposures of bleach, with and without light using an opposing-arch design. Visual and instrumental color measurements were obtained from eighty teeth before bleaching and seven days after treatment using two different shade guides, Vitapan Classical (VC), Vita Bleachedguide 3D-Master (BG) and an intraoral spectrophotometer. Data were analyzed using ANOVA, paired t-test, and Wilcoxon signed rank tests at the 0.05 level of significance.

Instrumental method revealed significant difference in color between treatment with light (DeltaE(ab)(*)=6.0) and without light (DeltaE(ab)(*)=4.7) after seven days (p<0.05). No differences were visually detected between treatment with light and without light using the VC (p=0.56). However, a significant difference was recorded using the BG (p<0.01). Instrumental measurements of color change were in better accordance with visual findings using the BG guide (R(2)=0.60) rather than the VC (R(2)=0.20).

Within the limitations of this study, the treatment with supplementary light showed significantly greater bleaching-dependent changes in color compared to treatment without light when assessed using instrumental methods. The same was determined for the visual method with Vita Bleachedguide 3D-Master. No significant difference in color change with respect to light exposure was detected for the Vitapan Classical.