A toothbrush that needs no battery and generates its own electricity may be more effective than conventional brushes at fighting the bacteria behind gum disease. Researchers led by Yanhui Lu at Peking University in China developed bristles made from a piezoelectric plastic, a material that produces an electric charge when it is bent. Each time a user brushes, the flexing bristles create a small current that triggers reactive oxygen species, molecules that damage bacteria.
In laboratory experiments, thicker versions of the bristles killed about 53 percent of Streptococcus mutans, the bacterium most associated with cavities, and 78 percent of Porphyromonas gingivalis, a bacterium linked to gum disease. Standard nylon bristles achieved kill rates of only 9 percent and 8 percent in the same tests. The device also removed more than 99 percent of plaque, compared with roughly 80 percent for nylon brushes.
The team also tested the brush in a clinical trial involving 109 adults who had plaque buildup and inflamed gums. Over three months, participants using the new brush saw plaque, gum inflammation and bleeding fall by about 40 percent. Those using nylon brushes saw reductions of about 15 percent. Earlier designs had tried to tackle oral bacteria using metal nanoparticle bristles or ionic brushes that depend on batteries, but the new approach avoids both drawbacks.
The stakes are considerable. Oral diseases affect nearly half of the world's population, making them among the most widespread health problems globally. Yet the findings are preliminary. The study did not show whether the brush prevents cavities or tooth loss, and larger trials will be needed before any such claim can be made. Nicholas Jakubovics of Newcastle University, who was not involved in the research, has noted that broader studies are necessary to confirm its benefits over everyday brushing.