Guide
Sonic vs ultrasonic toothbrush: what the terms mean
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In short
A sonic toothbrush vibrates its bristles at a frequency within the range humans can hear, which is where the name comes from; Philips Sonicare is a sonic brush. An ultrasonic toothbrush uses vibration above the range of human hearing, above about 20,000 vibrations per second, often from a special transducer in the head. Many brushes marketed as ultrasonic are really sonic, so check the specifications rather than the label.
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Toothbrush marketing uses the words sonic and ultrasonic freely, and some listings even mix them up. The two words describe different frequency ranges of vibration, and the brushes that use them work in different ways. This guide explains what each term means, where Philips Sonicare and other brands fit, how to read movement and frequency figures, and why the label alone tells you little about how a brush feels. It does not rank one as better for your teeth; the NHS guidance on brushing applies to all of them.
What sonic means
Sound is vibration. Humans hear roughly from 20 to 20,000 vibrations per second, called hertz. A sonic toothbrush vibrates its head within this audible range, typically a few hundred times per second. That is why it makes a distinct buzz.
Philips Sonicare listings quote movements per minute instead. The DiamondClean 9000 listing, for example, quotes up to 62,000 bristle movements per minute. Each side-to-side stroke counts as two movements, so that figure corresponds to a vibration in the audible range. See how does a sonic toothbrush work?.
What ultrasonic means
Ultrasound is vibration above the range of human hearing, above about 20,000 hertz. A true ultrasonic toothbrush has a transducer that produces ultrasound in the head, often far above that threshold, and some such brushes move the bristles very little or not at all. They rely on the ultrasound rather than bristle movement.
These brushes are much less common in the UK than sonic or oscillating brushes, and they usually need a special toothpaste or head. Check the maker's instructions carefully.
Side by side
The table sets out the general differences between the three common types.
| Type | How it works | Examples |
|---|---|---|
| Sonic | Head vibrates side to side in the audible range | Philips Sonicare, many other brands |
| Ultrasonic | Transducer produces ultrasound above 20,000 Hz | Specialist brands |
| Oscillating | Round head rotates back and forth, some also pulsate | Oral-B Pro, Oral-B iO |
Why labels can mislead
Some low-cost brushes are sold as ultrasonic when their specifications show a vibration rate in the sonic range. Others quote very large numbers of movements per minute that are hard to compare. The word on the box tells you less than the specification and the maker's description of how the brush works.
When comparing brushes, look at features you will notice every day: pressure feedback, modes, battery life, head choice and charging. Our best sonic electric toothbrush guide compares premium sonic handles on those points.
Where Philips Sonicare sits
Sonicare is a sonic brush. Its oval head sweeps side to side at high speed, and Philips describes the movement of fluid between the teeth as part of how it cleans. Every Sonicare, from the entry 3100 to the Prestige 9900, uses this sonic action. See Sonicare 3100 vs 4100 vs 5300 for the entry range and Philips Sonicare models compared for the premium handles.
What matters more than the label
The NHS says that both manual and electric brushes work well if used properly: twice a day, for about two minutes, with fluoride toothpaste, covering every surface. Technique, a light touch and changing the head regularly matter whatever type of brush you choose.
If you are deciding between Sonicare and Oral-B, our sonic vs oscillating and Oral-B iO vs Philips Sonicare articles compare the two main designs.
Noise and feel
Because sonic brushes vibrate in the audible range, they make a noticeable buzz and a tickling feel that takes some getting used to. Many Sonicare handles start gently with Easy-start and offer lower intensities. True ultrasonic brushes, working above hearing range, can be very quiet, though their motors and any bristle movement still make some sound. Oral-B's iO uses a magnetic drive that many people find quieter than older oscillating brushes.
Reading movement figures on a listing
Brush listings quote movements per minute, strokes per minute or vibrations per minute, and these are not always counted the same way. One side-to-side stroke can be counted as two movements, so a figure in movements may be double the same figure in strokes. Oscillating brushes quote oscillations and pulsations separately. Because of this, comparing numbers across brands rarely tells you much. Compare within one brand's range instead, where figures are counted the same way, and give more weight to features you will use every day.
Frequently asked questions
Is Sonicare ultrasonic? No. Sonicare is a sonic brush, vibrating in the audible range.
Is an ultrasonic toothbrush better than a sonic one? The NHS does not rank brush types. Choose one you will use properly twice a day.
Why does my sonic brush tickle? The fast vibration takes a few days to get used to. A lower intensity helps.
Do sonic and ultrasonic brushes use the same heads? No. Each uses heads designed for its own drive.
What you need
- Check price on AmazonAffiliate link
Sonicare Next-Gen 9900 Prestige: SenseIQ, 8 modes, display
- Check price on AmazonAffiliate link
Oral-B iO6: Sensitive and Super-Sensitive modes, display
From: Best electric toothbrushes in the UK: premium models compared