Even with regular brushing, teeth can become stained from genetic factors or consuming foods and drinks like tomatoes and coffee. Chemical whiteners can help, but they can also damage teeth in the process. So, researchers reporting in ACS Nano have designed a prototype teeth-whitening powder that is activated by the vibrations from an electric toothbrush. The system both brightened and protected teeth in lab demonstrations.
"This work offers a safe, at-home teeth whitening strategy integrating whitening, enamel repair and microbiome balance for long-term oral health," says Min Xing, first author on the study.
Peroxide-based bleaching with strips, gels and mouth rinses is a popular option among consumers for whitening stained teeth. This type of chemical whitening generates reactive oxygen species (ROS), compounds that break apart stain-causing molecules. But in addition to removing stains, many whitening techniques can damage the tooth enamel, which might result in easier re-staining or other oral problems. Now, Xing, Wenhao Qian, Xuanyong Liu, Jiajun Qiu and colleagues are developing a tooth-whitening compound that generates ROS when activated by electric toothbrush vibrations while strengthening and repairing teeth at the same time.
The researchers combined strontium and calcium ions with barium titanate in a solution and then heated and formed it into a ceramic powder, dubbed BSCT. When vibrated, the powder generates a small electric field - a phenomenon known as the piezoelectric effect - that causes ROS-generating chemical reactions.
In initial lab tests using human teeth artificially stained with tea and coffee, four hours of brushing with BSCT and an electric toothbrush caused visible whitening. After 12 hours of brushing, treated teeth were almost 50% whiter than the control group stained in the same way but brushed with saline. For teeth with damaged enamel and dentin, BSCT brushing regenerated these structural components because the strontium, calcium and barium ions included in the powder formed deposits on the tooth surface.
Next, researchers tested the powder on rats fed high-sugar diets. Daily brushing for one minute over four weeks using BSCT helped restore the rats' oral microbiome, killing periodontitis-causing Porphyromonas gingivalis and Staphylococcus aureus bacteria and reducing inflammation.
Though current tests haven't yet incorporated the BSCT powder into a toothpaste formula, researchers say that this study is a step toward a new effective, at-home treatment for safely whitening teeth and promoting oral health.
The authors acknowledge funding from the Youth Innovation Promotion Association of the Chinese Academy of Sciences, the Science and Technology Commission of Shanghai Municipality, the Shanghai Medical Key Specialty, the Medical Key Subject of Xuhui District, and the Opening Project of the State Key Laboratory of High Performance Ceramics.
