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Reactivation capacity of TiO2 nanoparticles for dental bleaching: an in vitro study
Journal article   Open access   Peer reviewed

Reactivation capacity of TiO2 nanoparticles for dental bleaching: an in vitro study

Suely Cristina Aragão Veras dos Santos, Tainah Oliveira Rifane, Isabel Silva do Nascimento, Lucca Reis Mesquita, Nayara Oliveira de Souza, Madiana Magalhães Moreira and Victor Pinheiro Feitosa
Brazilian dental journal, Vol.37, e25-6525
08/07/2026
DOI: 10.1590/0103-644020266525
url
https://doi.org/10.1590/0103-644020266525View
Published (Version of record) Open Access

Abstract

This study evaluated the bleaching efficacy, pH behavior, and reuse potential of a titanium dioxide nanoparticle (TiO₂) suspension as a photocatalytic, peroxide-free alternative to carbamide peroxide (CP) for at-home bleaching. Forty bovine incisors were subjected to a 21-day at-home bleaching regimen (2 h/day) using fresh or reused agents (n = 10): fresh CP (16% CP), reapplied CP (16% CP collected and reused), fresh TiO₂ (10 wt% TiO₂ suspension), and reapplied TiO₂ (reactivated 10 wt% TiO₂ suspension). TiO₂ suspensions were UV-activated daily (385 nm, 50 min), and the reused TiO₂ was reactivated prior to each application. The pH of the bleaching agents was assessed before gel application and after completion of the at-home protocol; all experimental groups showed a similar pH trend, with values increasing from 6.0 to 7.0 throughout the procedure. Bleaching efficacy was evaluated using CIEDE2000 (ΔE₀₀) and whiteness index (ΔWID) values obtained with a digital spectrophotometer (VITA Easyshade V). Data were analyzed with one-way ANOVA and Tukey’s test (α = 0.05). ΔE₀₀ analysis showed that fresh TiO₂ produced the lowest color change, with values closest to the perceptibility and acceptability thresholds, differing significantly from reapplied TiO₂, fresh CP, and reapplied CP (p < 0.05). No significant differences were observed among the remaining groups, and all other conditions exhibited ΔE₀₀ values above the acceptability threshold. ΔWID values did not differ significantly among groups (p = 0.475). The UV-activated TiO₂ suspension (100 min total exposure) was able to bleach teeth without peroxide.

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