Clinical evaluation of two in-office dental bleaching agents.

PURPOSE: To evaluate the bleaching efficacy and time required for color stability immediately after dental office bleaching.

METHODS: 40 subjects were randomly divided into two groups, according to the bleaching agent used:GHP - 35% hydrogen peroxide gel and GCP - 37% carbamide peroxide gel. The color was measured with a spectrophotometer before and immediately, 24 hours, 72 hours, 7 days and 15 days after the bleaching procedure. The color parameters were evaluated and the ΔE*, ΔL*, Δa* and Δb* values were calculated for each evaluation period. The data was statistically analyzed with Student's T-test, one-way ANOVA and Tukey's post hoc test (P ≤ 0.05).

RESULTS: Regarding the ΔE* values, in the assessed periods there were no significant differences between groups (P≥ 0.05). However, the luminosity (ΔL*) decreased considerably in both groups in the first 72 hours (P≤ 0.05), followed by an increase at 15 days (P≤ 0.05) in the hydrogen peroxide group. Regarding the Δb* values, the GHP showed higher negative alterations in the b* axis in the first 24 hours. The 37% carbamide peroxide gel and the 35% hydrogen peroxide gel were effective and there was no reversal of tooth color within 15 days; however a more accentuated bleaching effect was observed immediately after bleaching.

CLINICAL SIGNIFICANCE: Rapid bleaching was observed immediately after the in-office bleaching treatment.