What’s the difference between a sonic and ultrasonic electric toothbrush?
The vast majority of electric toothbrushes available on the market today use sonic technology. That includes the Philips Sonicare, the Colgate, the Oral-B brands and many more.
But, there is another type of sonic cleaning technology, it is called ultrasonic.
It is quite uncommon to see these types of toothbrushes, but they do exist.
In this post I will be taking a look at the key differences between the two types of brush, so that you understand how they are different.
To help summarise the content quickly, I have created an infographic as a quick reference point for all the key facts. We then summarise with text and include a video explanation.
Although there is text below that explains it all a video is better right?
The following video was taken from YouTube and was not created by myself, but it explains and demonstrates fantastically an ultrasonic toothbrush.
Sonic electric toothbrush
To be classified as a sonic toothbrush, the motion or vibration from the brush has to be quick enough to produce a ‘humming’ sound that is within the audible range of the human ear (20 Hz to 20,000 Hz).
Sonic brushes typically offer 12,000-24,000 oscillations or 24,000-48,000 movements per minute.
Sonic brushes rely on a sweeping motion alone to clean the teeth, the movement that they provide is often high in amplitude which means they offer larger sweeping brush stroke motions.
It is the bristles on the brush head that move at this speed to essentially brush away food particles and bacteria that sit on the teeth and gumline.
Sonic toothbrushes should not be confused with ultrasonic toothbrushes which operate at a much higher frequency and use ultrasound rather than the motion of the brush head to remove plaque and other bacteria.
Examples of a sonic brush include Oral-B’s range of electric brushes as well as Philips Sonicare range.
Ultrasonic electric toothbrush
An ultrasonic toothbrush does not rely on the physical motion of the brush head and bristles to clean the surfaces of the teeth.
Instead, an ultrasonic toothbrush uses a very high frequency of vibration, which is referred to as ultrasound to remove plaque and bacteria from the teeth.
Essentially it is sound waves, that are invisible to the human eye that is actually cleaning the teeth.
The classification of an ultrasonic toothbrush requires the brush to emit a wave of 20,000Hz or 2,400,000 movements per minute. This is considerably more than 12-48,000 of the very popular sonic electric toothbrushes that most of us know and relate to.
Within the USA, the Food and Drug Association (FDA) actually specify a minimum of 1.6MHz or 192,000,000 movements per minute.
The high frequency waves, but low in amplitude means the bacterial chains found in the mouth that make up plaque are broken up by the vibration and can work as far as 5mm below the gumline.
Where a sonic toothbrush requires the physical motion of the brush bristles to clean the teeth surfaces and gumline, the ultrasonic brush does not. You could simply rest it on each tooth.
However, many ultrasonic brushes do also provide additional sonic vibration ranging from 9,000 to 40,000 movements per minute, in order to provide additional sweeping motion which removes food particles and bacterial chain remnants.
By adding this additional sonic motion, it not only potentially makes the brush more practical, it more than anything makes it more acceptable, because society is not used to toothbrushes that don’t actually have bristles!
The following is a promotional video for Ultrasonic toothbrush manufacturer Megasonex, but it explains with visuals just how it works.
A brief buying guide: who makes the best ultrasonic toothbrush?
The market is dominated by Sonic toothbrushes, notably those from the largest household brands.
There are several toothbrushes that suggest they are ultrasonic, using such words in the product title and description, but in fact they are just standard sonic toothbrushes, operating at up to 48,000 movements per minute rather than using ultrasound to achieve the cleaning.
Of the 3 brands, it is only Emmi-Dent that are actively selling their products, with the others being virtually impossible to buy, so at this moment in time it looks like this is your best bet if you want an ultrasonic toothbrush.
Emmi-Dent is primarily sold within Europe, but you can buy their latest model on Amazon. (Please note: Be aware of the power adaptor supplied. You may need a plug and voltage converter for use within the USA.)
If you’re not specifically looking for ultrasonic, but rather a ‘standard’ electric toothbrush, check out our guide here that looks at the best sonic toothbrushes.
Many people ask what is the best ultrasonic toothbrush.
I have not had hands-on with any ultrasonic brushes to date. Yet, despite this, for me, there isn’t a ‘best’ brush.
This is because your options are extremely limited and in reality, sonic toothbrushes tend to a more logical purchase.
They are more readily available, generally cheaper and provide noticeable brushing enhancement over a manual brush, therefore making the need or justification for an ultrasonic toothbrush much more difficult.
If you are looking for side-by-side comparisons of sonic and ultrasonic electric toothbrush models, I can at this time confirm I or anyone else on the team has yet to write such comparisons as there is little demand for such. If you want to contact us, we will gladly help where we can, if you need further assistance.