Electricity-Generating Toothbrush Improves Plaque and Gum Measures in Small Trial

A toothbrush whose bristles generate electricity as they bend reduced plaque, gum inflammation and bleeding more than a conventional toothbrush in a small trial, New Scientist reported.

The device combines physical cleaning with chemical reactions intended to damage harmful bacteria. Researchers tested it in laboratory experiments and in 109 adults with dental plaque and inflamed gums.

According to New Scientist, Yanhui Lu at Peking University in China and colleagues developed the bristles using piezoelectric plastic, a material that generates electric charges under pressure.

Bending during brushing triggers reactions that produce reactive-oxygen species, molecules that damage bacterial membranes. The bristles simultaneously remove plaque through normal brushing movements.

The researchers produced two bristle thicknesses, both meeting Chinese national standards for softness and strength. Laboratory testing confirmed that pressure generated electricity, particularly in the thicker bristles. The brushes remained soft and retained their electrical properties after three months of use, New Scientist reported.

In laboratory comparisons, the thicker piezoelectric bristles killed about 53% of Streptococcus mutans, a bacterium associated with cavities, and 78% of Porphyromonas gingivalis, which contributes to gum disease. Conventional nylon bristles killed about 9% and 8%, respectively.

Another experiment used plaque collected from human mouths and grown on pieces of cow enamel. After three minutes of brushing, the new toothbrushes removed more than 99% of plaque, compared with about 80% for nylon brushes.

For the human trial, participants were randomly assigned to use either a piezoelectric toothbrush or a conventional nylon brush twice daily for three months.

Dental examinations found reductions of roughly 40% in plaque accumulation, gum inflammation and bleeding among participants using the experimental brushes. The corresponding reductions for conventional brushes were around 15%, according to New Scientist.

Genetic analysis also found a lower relative abundance of harmful bacteria and increases in some potentially beneficial bacteria in plaque from the experimental-brush group.

Nicholas Jakubovics at Newcastle University, who was not involved in the research, welcomed the approach but said larger studies must establish whether it prevents cavities and tooth loss.

The findings, published in Science Advances, concern improvements in plaque and gum measures rather than demonstrated prevention of those longer-term dental problems, New Scientist reported.

Sources

• New Scientist: Toothbrush that emits electricity may more effectively prevent gum disease