Clinical myths in dental bleaching: an evidence-based structured narrative review

This narrative review critically examines common myths in dental bleaching that are often presented as strategies to improve efficacy or reduce adverse effects, despite limited, inconsistent, or context-dependent clinical support. The review integrates evidence from clinical trials and systematic reviews identified through searches, with priority given to higher-level clinical evidence when available. In addition, concepts from Evidence-Based Practice and Cognitive Psychology are used to contextualize why weakly supported protocols may persist in clinical decision-making. The analysis addressed frequently disseminated beliefs in clinical practice and led to the following conclusions: a) dietary restriction does not improve bleaching outcomes; b) preventive use of analgesics and/or anti-inflammatory drugs does not reduce tooth sensitivity (TS); c) higher peroxide concentrations may accelerate early bleaching but increase adverse effects and do not enhance final efficacy; d) prolonged gel exposure beyond recommended times does not produce perceptible additional color change and may increase TS; e) tray scalloping does not consistently reduce patient-perceived gingival irritation; f) increasing gel volume or contact area does not improve final bleaching efficacy and may increase biological cost; g) light-activation does not provide additional clinical benefit; h) gel agitation does not enhance bleaching outcomes; i) over-the-counter products do not replace professionally supervised bleaching in terms of predictability and magnitude of color change; and j) desensitizing toothpastes show inconsistent efficacy in preventing TS. Overall, bleaching protocols should be selected according to clinically meaningful benefits, adverse effects, patient-centered outcomes, and the strength and consistency of the available evidence, rather than tradition, intuition, or commercial appeal.