Emmi-dent. It's the toothbrush you're not supposed to brush your teeth with. But that's not to say you shouldn't use it regularly.
Like any other toothbrush, Emmi-dent has a head full of bristles. But they're for transmitting ultrasonic impulses from a microchip inside the brush head. When these impulses interact with Emmi-dent's own toothpaste, they cause millions of infinitesimal "nano-bubbles" to form and then collapse. To the bacteria in your mouth, this mass bubble implosion is cataclysmic. The energy released breaks their outer membranes and they die.
"No bacteria equals no plaque, no calculus, no problems," says Peer Blumenschein, chief executive of Emmi Ultrasonic AG in Basel, Switzerland, the parent company of Emmi-Tech Inc. in Canton, Mass. (Calculus, or tartar, is a hardened form of plaque, and that's the sticky coating of bacteria you feel on your teeth before brushing.)
Of course, you may already have tartar on your teeth, and the Emmi-dent "will reduce it over a period of several months," says Stephen Spector, president of Emmi-Tech.
To use an Emmi-dent brush, you hold its bristles on your teeth without moving them at all. "It cleans places you can't reach with bristles or even floss. And it restores the original natural color of your teeth," Spector says.
The Emmi-dent (www.emmi-dent.com, $189) requires no abrasive brushing, and there are no abrasives in the special toothpaste, Spector says.
Not everyone agrees that those are vital concerns. "Enamel is the hardest substance in the body," says Dr. Vladimir Spolsky, an associate professor at the UCLA School of Dentistry. "You can't remove it by brushing."
While Emmi-dent brushes have been available in this country for less than a year, they've been sold in Europe since 2008. Two unpublished studies there found that the brushes were effective in reducing plaque and keeping gums healthy.
The Emmi-dent may be the only no-brushing-required toothbrush on the market, but it's not alone in boasting of bubble-bursting bacteria-busting effects. Sonic brushes, which vibrate multiple times faster than other power brushes, have made the same claim. Indeed, even some slower power brushes have been shown to remove plaque without bristle contact.
These other power brushes have not been tested against the Emmi-dent. But a 2010 study in the American Journal of Dentistry tested them against a brush that combined sonic and ultrasonic technology.
The brush with the combined technologies was the UItreo, which partially funded the study.
The study was done in the lab, with plaque grown not on people's teeth but on disks simulating them. In the testing, three brushes — the Ultreo, a commercially available power brush with oscillating/rotating bristles, and a commercially available sonic brush — were held 3 millimeters from the disks.
All three brushes removed some of the plaque on the disks, but the Ultreo (www.ultreo.com) removed nearly two-thirds of it, significantly more than the others.
Unlike the Emmi-dent, the Ultreo doesn't transmit ultrasonic waves through its bristles. Those are simply for brushing, which is considered an important part of the cleaning it does.
The ultrasonic waves, intended to clean areas the bristles can't reach, are sent by a so-called wave guide in the center of the head.
Perhaps because research is so hard to do — keeping tabs on people's brushing habits is awkward, to say the least — there's very little solid evidence that any particular type of brush is better than any other. A 2011 Cochrane review of studies comparing different types of power brushes did not lead to definitive results. A 2009 review did conclude that power brushes with rotating/oscillating bristles are better than manual brushes at removing plaque and protecting against gum inflammation.
"But if you use it properly, you can do an excellent job with a manual," Spolsky says. "Of course, not many people do."