Powered brushes can be very, well, powerful, which explains why they can do such a thorough job on plaque. But too much power may also be potentially problematic.
A 2017 study, published in the journal PLOS One, found that powered brushes were more likely than manual to abrade dentin—the tissue directly below the tooth’s enamel, which can become exposed when enamel wears away or gums recede. Abrasions to the dentin increase tooth sensitivity and can hike cavity risks.
For the study, researchers took dentin samples from teeth and then used a machine that simulated the effects of eight-and-a-half years of brushing. They found that sonic toothbrushes caused the most abrasion to the dentin, followed by oscillating, and that manual brushes—especially those with rippled bristles—created the least.
Another simulated brushing study, this one published in 2013 in the journal Clinical Oral Investigations, had somewhat different results. It found that manual and powered brushes had similar effects on intact enamel, but that on worn enamel, manual toothbrush abraded dentin more.
But there’s an important caveat: In this study, the manual brushing simulation used a lot more force than the powered brush simulation. And experts say that brushing too forcefully with any kind of brush may increase the likelihood of gum recession and damaged tooth enamel.
In fact, a gentle touch with a soft-bristled brush—whether manual or electric—is the safest bet. “It doesn’t take much force to brush away bacteria and food particles,” says Vera W. L. Tang., D.D.S., clinical assistant professor, vice-chair and predoctoral director at the New York University College of Dentistry, department of periodontology and implant dentistry.
And that may be especially important to keep in mind with powered brushes. “When you brush with a powered toothbrush, you don’t really have to do anything because the rotating or vibrating head does the work for you,” Tang says.