Some rotate to clean your teeth, while others vibrate.
And some have features such as a timer or pressure sensor.
Electric toothbrushes can basically be divided into three categories.
Oscillating rotary toothbrushes have small circular heads that rotate back and forth to clean each tooth.
They typically oscillate laterally several thousand times per minute, and also rotate back and forth at a 50° to 70° angle, according to German consumer watchdog Stiftung Warentest.
Some have a pulsing feature as well.
“This is meant to dislodge more dental plaque,” explains dentist Dr Stefan Zimmer, a professor in the Department of Dental, Oral and Maxillofacial Medicine at Witten/Herdecke University in Germany.
Sonic toothbrushes, on the other hand, have an oblong, vibrating head that moves bristles side-to-side at speeds high enough to produce an audible hum.
They make between 13,000 and 40,000 movements per minute, according to Stiftung Warentest.
“The average frequency is about 250 hertz,” says Dr Zimmer.
Ultrasonic toothbrushes make up the third category.
They use a much higher frequency of vibration, beyond the range of human hearing.
But they play only a minor role in the mass market, according to Dirk Kropp, managing director of proDente, a Cologne-based dental health information organisation.
When it comes to cleaning efficiency, there’s little difference between oscillating rotary and sonic/ultrasonic toothbrushes, says Stiftung Warentest’s Lea Sophie Lukas.
So your choice depends more on your brushing technique and diligence.
If you use an oscillating rotary toothbrush, you have got to brush each tooth individually for several seconds, according to Stiftung Warentest.
You should also move the brush head into the interdental spaces.
A sonic/ultrasonic toothbrush cleans several teeth at once, Lukas notes, so it’s the better choice if you don’t brush very carefully.
“A sonic toothbrush is more forgiving if you don’t have the proper brushing technique,” remarks Dr Zimmer.
Its greatest advantage, he says, is that you can use it like a manual toothbrush.
If you tend to press too hard when brushing, it’s a good idea to get an electric toothbrush with a pressure sensor, advises Kropp.
If you press too hard, it reacts by blinking or humming.
“Some brushes that don’t cost an arm and a leg also have this feature,” Lukas says.
Stiftung Warentest recently did a study on electric toothbrushes, and one of its recommendations is to not only consider the purchase price, but also follow-up costs.
Consumers should inquire about the price of brush heads, which Lukas says should be replaced every three months.
No matter which toothbrush type you choose, effective cleaning depends in no small part on how much time you spend brushing.
“You shouldn’t brush for less than two minutes,” advises Lukas, who says it’s therefore a good thing that some of the less expensive electric toothbrushes now also have a timer or give a regular signal to ensure that you spend equal time brushing each quadrant of your mouth.
Dr Zimmer emphasises, however, that as no two sets of teeth are alike, sufficient brushing time varies from person to person. – By Bernadette Winter/dpa