The increasing demand for a whiter smile has resulted in an increased popularity for tooth whitening procedures. The most classic hydrogen peroxide-based whitening agents are effective, but can lead to enamel demineralization, gingival irritation, or cytotoxicity. Furthermore, these techniques are excessively time-consuming. Here, we report a nondestructive, harmless and convenient tooth whitening strategy based on a piezo-catalysis effect realized by replacement of abrasives traditionally used in toothpaste with piezoelectric particles. Degradation of organic dyes via piezo-catalysis of BaTiO 3 (BTO) nanoparticles was performed under ultrasonic vibration to simulate daily tooth brushing. Teeth stained with black tea, blueberry juice, wine or a combination thereof can be notably whitened by the poled BTO turbid liquid after vibration for 3 h. A similar treatment using unpoled or cubic BTO show negligible tooth whitening effect. Furthermore, the BTO nanoparticle-based piezocatalysis tooth whitening procedure exhibits remarkably less damage to both enamel and biological cells.

Flexoelectricity has trigged emergent phenomena and functionalities, such as flexo‐resistance, flexo‐photovoltaic, photo‐flexoelectric, flexo‐electronics and so on. Analogous to piezocatalysis, the flexoelectric effect can provide a novel mechanism to enhance the sonochemical redox reactions. Here, by extending flexoelectricity to electrochemical functionality, an unprecedented phenomenon is demonstrated of flexo‐catalysis effect in centrosymmetric nanoparticles to degrade organic dyes. Simulations have been performed to elucidate the bubble cavitation induced strain gradients and polarization variation, and in turn the flexoelectricity induced reactive species have been verified by trapping experiment. The flexo‐catalytic results show that more than 92.2% of Rhodamine B can be degraded at a rate of ≈k = 0.6 h−1. This finding not only suggests a new strategy to generate the flexoelectric effect, but also opens up the possibility to extend existing catalytic techniques.