Effect of low-concentration at-home bleaching gels on whitening and tooth sensitivity: a split mouth randomized...

To assess the bleaching efficacy, tooth sensitivity, enamel surface morphology, and oral health-related quality of life (OHRQoL) of two at-home bleaching products with matched effective hydrogen peroxide (HP) concentrations: Beyke iWhite (8% carbamide peroxide) and Invisalign (3% hydrogen peroxide).

A randomized, triple-blind, split-mouth clinical trial was conducted with 22 participants undergoing a two-week bleaching treatment. The gel was used daily for 6-8 h. Tooth color and OHRQoL were assessed at baseline, post-bleaching, and 1-month follow-up. Tooth color was measured using a spectrophotometer (ΔE₀₀), while OHRQoL was evaluated using psychological questionnaires (OHIP and PIDAQ questionnaires). Daily tooth sensitivity reports were collected, and enamel morphology was analyzed using scanning electron microscopy. An in vitro experiment tracked the initial pH values of gels and their 8 h changes on bovine enamel. Statistical analysis included Wilcoxon Signed Rank tests for tooth sensitivity and questionnaires, paired t-tests for color change (ΔE₀₀), and ANOVA for pH changes.

Both products presented effective color change (ΔE₀₀ = 5.39 ± 2.50 for 3% HP and ΔE₀₀ = 4.75 ± 2.25 for 8% CP) after two weeks, exceeding clinical acceptability thresholds (ΔE₀₀ >1.8). The 3% HP gel yielded a statistically greater color change than the 8% CP gel (p < 0.05). The 8% CP gel induced statistically lower tooth sensitivity (NRS/VAS, p < 0.05), while both reported mild sensitivity (0 < NRS < 1.5, 0 < VAS < 3). OHRQoL improved significantly (P < 0.05). Invisalign treatment led to more noticeable surface undulations than Beyke iWhite. The in vitro experiment indicated Beyke iWhite gel was initially alkaline, turning neutral, while Invisalign gel remained acidic.

Both products effectively whitened teeth while inducing mild tooth sensitivity, and both had a positive socio-psychological impact. The 3% HP gel provided a bleaching efficacy advantage, while the 8% CP gel demonstrated lower sensitivity and less enamel alteration.

Clinicians may consider at-home bleaching techniques with 3% HP and 8% CP to obtain effective bleaching results with slight side effects.

Chinese Clinical Trial Registry ChiCTR2400092807, 24/11/2024, Retrospectively registered.