Powered toothbrushes with circular bristle heads that rotate in alternating directions are better at removing plaque and reducing the risk of gum disease than ordinary manual toothbrushes, a review of recent studies concludes.
Over the short term of one to three months, the rotating brushes reduced plaque by 11 percent over manual toothbrushes and reduced the signs of gingivitis, or gum inflammation, by 6 percent over the regular brushes, according to Peter Robinson of Sheffield University in Sheffield, England, and colleagues.
The powered brushes reduced gingivitis by 17 percent over the manual brushes after more than three months’ use. The researchers found no evidence that powered brushes of any kind caused more gum damage than manual brushes.
Despite the better performance by the rotating powered brushes, the benefits of regular brushing “occur whether the brush is manual or powered, and the results of this review do not indicate that toothbrushing is only worthwhile with a powered toothbrush,” the researchers write.
“We did not want to say that electric brushes are necessary, just that they can help. It is possible to clean one's teeth perfectly well without an electric brush,” Robinson says.
The review appears in the April issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
The review by Robinson and colleagues included 42 studies and 3,855 participants. The studies compared manual, electric and battery-powered toothbrushes with a variety of bristle arrangements and motions and newer “ionic” brushes that buzz the tooth surface with small electric charges.
Ionic brushes and powered brushes that did not use a circular, alternating motion were no better than manual toothbrushes in removing plaque and preventing gingivitis over one to three months, Robinson and colleagues conclude.
Although the rotating powered brush seems more effective than the manual toothbrush, Robinson acknowledges that there is no standard for measuring how much of a reduction in plaque and gum inflammation is necessary to cause clinically significant improvements in oral health.
“There are standards proposed but they are arbitrary,” Robinson says. “We can be reasonably sure that plaque causes periodontitis, and even that more plaque causes more periodontitis. But we cannot be sure by how much we need to reduce plaque levels in order to have a long term effect on periodontitis.”
The lack of standards makes it difficult to compare cost-effectiveness among the different types of brushes, according to the researchers, who found no such comparisons in their review.
“Most people clean their teeth not to ward off gum disease but to feel fresh and confident. Likewise, some people simply enjoy gadgets. It would be difficult to put a value on those things,” Robinson says.
Powered toothbrush manufacturers funded — at least in part — 28 of the studies in the review, while the rest of the studies were unclear as to funding. The researchers conducted statistical tests to determine whether industry funding biased the studies’ results in any way, and found no evidence of bias.
Fred Peterson, a spokesperson for the American Dental Association, says the association has no official recommendation regarding manual versus powered toothbrushes.
“Both manual and powered toothbrushes can effectively clean your teeth. If you have arthritis or otherwise need assistance with movement, a powered brush may be easier to use,” Peterson says.
Robinson says more studies are needed to determine whether the apparent advantage of rotating powered toothbrushes lasts more than three months.