Comparative Effects of Hydrogen Peroxide–Containing Whitening Toothpaste and Gel on Tooth Lightness: An In Vitro Study

Objective: This in vitro study aimed to compare changes in tooth lightness following repeated application of a whitening toothpaste and a whitening gel containing different concentrations of hydrogen peroxide.Methods: Ninety enamel specimens were prepared from extracted bovine incisors and artificially stained using black tea.The specimens were randomly allocated into three groups: a negative control group using a general toothpaste, a positive control group using a whitening toothpaste containing 0.75% hydrogen peroxide, and an experimental group using a whitening gel containing 2.8% hydrogen peroxide (n=30 per group).Each whitening agent was mixed with distilled water at a 1:2 ratio and applied by tooth brushing three times daily for 15 seconds over a 30-day period.Tooth color was measured at baseline and at 3-day intervals using a dental spectrophotometer (VITA Easyshade® Advance V) based on the VITA classical A1-D4 Ⓡ and VITA SYSTEM 3D-MASTER Ⓡ shade systems.Data were analyzed using one-way ANOVA and paired t-tests.Results: Both hydrogen peroxide-containing whitening products demonstrated significantly greater improvements in tooth lightness compared with the general toothpaste (p<0.05).Significant intergroup differences were observed between the negative control group and the hydrogen peroxide-containing groups; however, no statistically significant differences were found between the whitening toothpaste and the whitening gel throughout the experimental period (p＞0.05).Conclusion: Hydrogen peroxide-containing over-the-counter whitening products were effective in improving tooth lightness compared with a conventional toothpaste.However, differences in hydrogen peroxide concentration and formulation did not result in significant differences in whitening efficacy under the experimental conditions used in this study.