In-office tooth bleaching protocols: an umbrella review of systematic reviews and meta-analyses on whitening efficacy and tooth sensitivity

In-office tooth bleaching is widely used for rapid aesthetic improvement, but the clinical value of protocol variations-such as peroxide concentration, light activation, gel application methods, and desensitizing strategies-remains uncertain. This umbrella review synthesized systematic reviews and meta-analyses evaluating the effects of in-office bleaching protocols on whitening efficacy and tooth sensitivity. PubMed, Scopus, and Web of Science were searched from database inception to January 2026. Eligible studies were systematic reviews or meta-analyses assessing in-office bleaching of vital permanent teeth in adults. Methodological quality was assessed using AMSTAR-2, and certainty of evidence for major clinical questions was evaluated using GRADE. Due to protocol heterogeneity, findings were synthesized narratively with emphasis on results from higher-quality reviews. Twenty-four systematic reviews were included. Moderate-certainty evidence indicated that low-to-medium hydrogen peroxide concentrations (≈25-35%) produce whitening outcomes comparable to higher concentrations while reducing tooth sensitivity. Light activation (LED, halogen, or laser) generally did not improve whitening efficacy and may increase sensitivity. A recent meta-analysis suggested that violet-light activation combined with carbamide peroxide may enhance whitening without increasing sensitivity; however, supporting evidence remains limited. Single gel application protocols showed similar whitening outcomes to repeated gel renewals, with a tendency toward lower sensitivity. Desensitizing agents, particularly potassium nitrate and sodium fluoride, consistently reduced sensitivity without affecting whitening efficacy. Moderate peroxide concentrations, simplified gel application strategies, and desensitizing approaches may optimize in-office bleaching while minimizing sensitivity. Evidence supporting light activation and photobiomodulation remains limited, highlighting the need for well-designed randomized clinical trials.