Ultrasonic toothbrush

The humble toothbrush has come a long way from being a “humble” toothbrush. As this necessary evil of a toiletry has progressed from a stick with a few bristles to this:


If you are looking to buy an ultrasonic toothbrush and you don’t wish to read our entire guide, our recommendation is the Smilex AU-300E

our idea of dental care has also evolved from scrubbing our enamels like bathroom tiles to a much more refined and sophisticated routine that involves adequate intake of calcium, flossing our teeth, massaging our gums, cleaning our tongues and scrubbing our enamels like bathroom tiles. Our initially mild distaste for scraping off plaque with frayed twigs has also evolved into a more refined and sophisticated hatred of regimented brushing.

Being forced to perform a bi-daily ritual of shoving an unpleasant-tasting, abrasive and gag-inducing plastic stick in and out of every corner of your mouth in a uniquely frustrating and repetitive manner while being held hostage by the fear that your teeth might fall out after a paralyzing period of periodontal pain if you skip one too many of these agonizingly tedious sessions borders on the criminal. Like doing your taxes, becoming better at it only deepens and enriches your loathing for it.

Homo Sapiens being the particularly innovative geniuses in laziness that we are,  we quickly developed electric toothbrushes with brush heads that rapidly oscillated back-and-forth automatically resulting in reduced stress, reduced risk of carpal tunnel syndrome and reduced incidences of paid medical leave.

This ushered in a long and prosperous period of increased happiness, better health and improved productivity, ultimately culminating in the digital revolution that produced such wonders as the world wide web and Chinese-manufactured-California-designed electronics. To this day very few are aware of the role of the electric toothbrush in the birth of the internet and industrial globalization.

Meanwhile, electric toothbrushes themselves had become so advanced that they were now rapidly oscillating back-and-forth more than 30,000 times per minute. It was getting to the point where a new model with 35,000 rapidly oscillating back-and-forth strokes per minute simply didn’t sound that much more impressive than 30,000 rapidly oscillating back-and-forth strokes per minute.

Something different was needed to wow the toothbrush-wielding masses, something more impressive – perhaps something with an impressive numerical value. Hence was born the ultrasonic toothbrush, boasting in excess of 1,200,000 enamel-shattering ultrasound “vibrations” per minute.

What is an ultrasonic toothbrush?

In short: Ultrasonic toothbrush is a toothbrush that produces ultrasonic vibrating speeds that have a frequency of 20,000 hertz. There is a staggering amount of misleading and erroneous information about ultrasonic toothbrushes scattered around the big bad internet with some unscrupulous manufacturers calling their electric toothbrushes “ultrasonic toothbrushes” when they are anything but. Ultrasonic frequencies begin at 20,000 hertz. An electric toothbrush advertised as having a frequency of 30,000 brush strokes a minute is not running at an “ultrasonic frequency” as hertz is defined as the number of cycles per second, not per minute. The latter would be operating at a frequency of 500 hertz, which regretfully is just 19,500 hertz short of being ultrasonic.

In short, a true ultrasonic toothbrush is one that actually contains an embedded ultrasound generator. Which is a bit like saying true vegetable shortening contains trans fats, i.e. not saying much. In my book the ultrasonic toothbrush has been used, it has been rinsed and it has been found wanting.

cleaning teeth with toothbrush

The brush head on an ultrasonic toothbrush doesn’t actually oscillate, rotate or move at all – picture a plain manual toothbrush thoughtfully duct-taped onto an ultrasound transducer. It takes a Bruce Lee caliber of concentration to keep the brush head at an “optimal” distance from your teeth as the vibrations are so difficult to feel. Once the “cool” factor wears off this sort of becomes a pain-in-the-ass, which is sort of ironic since the whole point of an electric toothbrush is to make cleaning your teeth less of a pain-in-the-ass.

Another pain-in-the-ass is that because you’re relying purely on ultrasound vibrations to clear your teeth of solid plaque and ultrasound requires fluids to be transmitted effectively, you need to keep your mouth constantly filled with a saliva/toothpaste mixture of just the right consistency (read: watery) for optimal ultrasound transmission. This, apart from sounding absolutely and utterly disgusting and being a potential precursor to a watery toothpaste spill disaster, is also hard to do without causing said watery toothpaste spill disaster when trying to reach certain parts of your teeth. Parts of your teeth that you have always been able to reach with an ordinary toothbrush.

So far I have been ranting under the assumption that an ultrasonic toothbrush actually does its job if it is used properly. It doesn’t, which therefore renders all of the above meaningless. The main problem is that the ultrasound transducer in an ultrasonic toothbrush is much smaller (and thus weaker) than those found in ultrasonic cleaning tanks1 used to clean optical and medical equipment. It just screams “poor application of technology that serves more of a marketing purpose than a problem-solving one”.

Are ultrasonic toothbrushes safe?

Ultrasound has been used in medicine for over 50 years and it has been tested numerous times. In 1992 the FDA allowed the use of ultrasound at frequency of 1.6 MHz in a toothbrush and concluded that ultrasonic toothbrushes are safe to use.

Is ultrasonic toothbrush better than sonic?

Our verdict is that you’re better off with a much less snazzy-sounding but tried-and-tested “sonic toothbrush” with the brush heads of most models today rapidly oscillating back-and-forth more than 30,000 times per minute (using the word “sonic” to describe a modern electric toothbrush is moot since an electric toothbrush with a paltry 1,200 strokes per minute is already “sonic”, i.e. within the frequency of human hearing which begins at 20Hz).

Which one to buy?

If you are looking for an ultrasonic toothbrush no matter what, our recommendation is the Smilex AU-300E. It produces 1.6 million ultrasonic waves per second and 18.000 sonic waves per minute and its efficiency is backed by several clinical studies. However, it only offers a single cleaning mode and it costs nearly the same as the top rated sonic toothbrushes on our website.

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