16% Carbamide Peroxide Home Bleaching: Soft vs. Rigid Tray in a Randomized Blinded Equivalence Trial

The aim of this clinical study is to evaluate patient satisfaction, bleaching efficacy, and the risk and severity of tooth sensitivity and gingival irritation during home bleaching with 16% carbamide peroxide using conventional (soft) trays or rigid trays. A total of 100 patients will be selected to undergo home bleaching with either soft or rigid trays (n=50). Bleaching will be performed with 16% carbamide peroxide (Whiteness Perfect 16%, FGM, Joinville, SC, Brazil) for 2 hours daily for 3 weeks (21 days). Patient satisfaction will be assessed initially, weekly during the 3 weeks of treatment, and one month after completion of treatment using a questionnaire based on a visual analogue scale (VAS) from 0 to 10. Tooth colour will be assessed at baseline, 1 and 3 weeks during treatment, and 1, 6 and 12 months after treatment using the VITA Easyshade V spectrophotometer and the VITA Classical and VITA Linearguide 3D-MASTER scales (VITA Zahnfabrik, Bad Säckingen, Germany). The risk and intensity of tooth sensitivity and gingival irritation were recorded in a diary using a 0-10 VAS during treatment. Patient satisfaction data were analysed using Student's paired t-test. Colour change will be compared between groups using Student's t-test. The absolute risk of tooth sensitivity and gingival irritation was compared between groups using Fisher's exact test. Relative risk and confidence intervals (CI) were also calculated. The intensity of dental sensitivity and gingival irritation was analysed using Student's t-test for independent samples. The significance level will be set at 5% for all statistical tests.