PURPOSE: There is still controversy as to the efficacy of light activation used in tooth whitening. The purpose of this study was to evaluate the effect of light activation on tooth color change relative to the artificial dye color. MATERIALS AND METHODS: Extracted human third molars (160) were randomly distributed into eight groups of 20 specimens each based on artificial staining and use of light activation. All groups received three 45-minute sessions of in-office whitening at 3-day intervals. Color measurements were performed with an intraoral spectrophotometer at baseline prior to staining (T0), after artificial staining (T1), 1-day--(T2), and 1-week--(T3) post-whitening. Color differences were calculated relative to after artificial staining color parameters (L*1, a*1, b*1) with the use of a software analysis program enabling synchronization of two images. RESULTS: Within the same staining groups, the light-activated samples exhibited a greater color change than their nonlight-activated counterparts. However, only in the case of the yellow-stained samples at 1-day post-whitening was there a significant difference between the nonlight-activated and light-activated groups (Tukey's post hoc multiple comparison test for pairwise comparisons, p < 0.05). CONCLUSIONS: Light activation is a valid method for enhancing the efficacy of tooth whitening with respect to overall color change and works best with yellow stains. CLINICAL SIGNIFICANCE: Light activation is a valid method for enhancing the efficacy of tooth whitening with respect to overall color change and works best with yellow stains.
PURPOSE: There is still controversy as to the efficacy of light activation used in tooth whitening. The purpose of this study was to evaluate the effect of light activation on tooth color change relative to the artificial dye color. MATERIALS AND METHODS: Extracted human third molars (160) were randomly distributed into eight groups of 20 specimens each based on artificial staining and use of light activation. All groups received three 45-minute sessions of in-office whitening at 3-day intervals. Color measurements were performed with an intraoral spectrophotometer at baseline prior to staining (T0), after artificial staining (T1), 1-day--(T2), and 1-week--(T3) post-whitening. Color differences were calculated relative to after artificial staining color parameters (L*1, a*1, b*1) with the use of a software analysis program enabling synchronization of two images. RESULTS: Within the same staining groups, the light-activated samples exhibited a greater color change than their nonlight-activated counterparts. However, only in the case of the yellow-stained samples at 1-day post-whitening was there a significant difference between the nonlight-activated and light-activated groups (Tukey's post hoc multiple comparison test for pairwise comparisons, p < 0.05). CONCLUSIONS: Light activation is a valid method for enhancing the efficacy of tooth whitening with respect to overall color change and works best with yellow stains. CLINICAL SIGNIFICANCE: Light activation is a valid method for enhancing the efficacy of tooth whitening with respect to overall color change and works best with yellow stains.