RESUMO
OBJECTIVES: To investigate the effectiveness of two home bleaching modalities on whitening of tetracycline-stained teeth (TST). METHODS: A randomized controlled trial on the bleaching effect of 15% carbamide peroxide gel loaded in tray and 6.5% hydrogen peroxide strip in subjects with TST was performed. Eligible subjects were judged independently by two assessors, and randomly assigned into the tray or the strip group. Lightness (L*), redness (a*) and yellowness (b*) were measured with colorimeter at baseline, one, two and three months. Any adverse reaction associated with bleaching were also recorded. Overall colour changes (ΔE) were analysed by one-sample and independent t-test/Wilcoxon test at significance level α=0.05. RESULT: Twelve and fourteen participants were allocated to the tray and the strip group respectively. Both groups experienced noticeable and significant L*a*b* improvement at the end of the trial in comparison to the baseline (p<0.05). Significant improvement was observed in the first month for the tray group (p<0.05) and in the first two months for the strip group (p<0.05). While greater lightness improvement was observed in the tray group over the strip group in the first month (p=0.02), the reverse was noticed in the second month (p=0.01). There was no difference between two groups at the end of this trial (p<0.05) and no significant adverse reactions were observed. CONCLUSION: Over a three-month period, 6.0% hydrogen peroxide strip performed equally well as the 15% carbamide peroxide tray delivery system in TST. CLINICAL SIGNIFICANCE: Home bleaching systems produce noticeable tooth whitening effect in subjects with tetracycline-stained teeth.