Oral care · The evidence

The plaque you keep missing is not where you are scrubbing

A crossover study set a sonic brush against an ADA accepted manual one. The widest gaps landed where bristles barely reach.

Published August 13, 2026 · 8 minute read

Most people brush the way they scrub a pan. More pressure, more speed, more elbow. The instinct is reasonable, because for almost every other cleaning job in the house force is the variable that works. It is also the reason a lot of careful, conscientious brushers still hear the same sentence twice a year in the dental chair.

The two places plaque survives are the two places pressure cannot go: just under the gum margin, and in the flat contact between two teeth. Neither of them opens up because you pushed harder. That is the whole argument, and the brand with the most to gain from telling you otherwise says it out loud on its own product page.

The company selling you the brush tells you not to press

BURST sells sonic toothbrushes. It has every commercial reason to describe brushing as a power contest it happens to win. Instead, buried in the frequently asked questions under the buy button, it publishes this:

Read the last four words again. Just as well. Softer is not a comfort compromise you accept in exchange for a weaker clean. On the measure that matters, plaque and debris removed, the soft bristle is not behind. What it avoids is the receding gum line and the sensitivity that come with the hard one.

So if force is not the lever, something else has to be. BURST publishes what it thinks that something is, and unusually, it publishes the file.

Start with the asterisk

Every box carries the same claim with a small star beside it: removes up to 10x more plaque*. Most brands hope the star goes unread. BURST prints what it points to, at the bottom of the same page:

That footnote is an invitation, and it is worth taking. The clinical data page hosts the study abstracts as downloadable documents, product by product. The one behind the sonic brush is a short, plain document, and the headline multiple is not the interesting part of it.

What the study actually did

It is a single use, two period crossover trial. Crossover means nobody is stuck in the losing arm: every participant used both brushes, in a random order, at two separate visits. It is a design that removes the most obvious objection to a brand funded comparison, which is that the two groups were never the same people.

Participants

32 volunteers, 18 to 65 years old

Comparator

An ADA accepted manual soft toothbrush

Brushing

Two minutes, fluoride toothpaste, whitening mode

Run in

Three days twice daily with each assigned brush

Measurement

Plaque scored before and after brushing, supervised on site

Sites scored

Whole mouth, between the teeth, along the gumline

Both brushes worked. That is the first result in the document and it deserves to be said plainly: the manual brush significantly reduced plaque too, at every site. Anyone telling you a manual toothbrush does nothing is selling something.

The finding is not that one cleans and the other does not. It is how unevenly the gap is distributed across the mouth.

Three numbers, and only one of them is a slogan

Measured against the ADA accepted manual brush, in the same mouths, the sonic brush delivered:

Multiples relative to an ADA accepted manual soft toothbrush. All site comparisons reached p < 0.001. Source: BURST clinical evaluation of plaque removal, Pro sonic toothbrush.

Expressed the other way, as extra plaque actually removed, the same study records 16.7% more between the teeth and 48.7% more along the gumline.

Sit with the shape of that for a second. The gumline and the interdental contact are the hardest places in the mouth to reach, and they are exactly where the difference between the two brushes is largest. The sonic brush is not winning on the broad, flat, easy front surfaces you can already see in the mirror. It is winning in the two crevices you have been trying to solve with pressure.

Why pressure loses in exactly those two places

Here is BURST describing the geometry of its own bristle, again on the product page:

A toothpick works because it is thin and because it goes in. Nobody has ever cleaned between two teeth by pressing a toothpick flat against them. The same is true of a bristle: what gets it into a space narrower than itself is a fine tip arriving upright, not a heavier hand. Lean on the head and the tips bend away from the vertical, the mat splays sideways, and the working end of every filament ends up polishing the one surface that was never the problem.

The brush is built to stop you

Knowing that pressure is the wrong lever does not stop anyone from pressing. It is a reflex, it happens at six in the morning, and no one is thinking about bristle geometry with their eyes half shut. Which is why the interesting engineering on this brush is not the motor.

The brush pushes back. Lean on it and the motor drops out from under you, which is a far more effective correction than any instruction printed on a box, because it happens in the half second you are doing the thing wrong. BURST describes the same feature elsewhere as a pressure score that “helps prevent excessive pressure on sensitive teeth and gums”, and it works in both directions: too light and the brush tells you that too.

Then, when the two minutes are up, it grades you. In BURST's words: “After two minutes of brushing, your brush will give you a nifty score to tell you how well you did.” A score is a small thing. It is also the only feedback most people will ever get between one dental appointment and the next.

The other lever is time, and almost nobody serves the full two minutes

Two minutes is a long time when you are standing at a sink. It is the number every dental professional repeats, and it is the number almost everyone rounds down without noticing.

The study asked participants about that directly, and the questionnaire result is the one number in the whole document with no qualifier attached:

The mechanism is unglamorous: a timer on the display, and a pulse every thirty seconds telling you to move to the next quadrant of your mouth. It converts an abstract instruction into four small, finishable jobs. Owners describe the effect in exactly those terms.

What it felt like to the people in the study

Plaque scores are the objective half. The questionnaire is the half that predicts whether anyone keeps using the thing. The same 32 people answered about both brushes, which makes the spread unusually readable.

The 15.6% line is the one worth staring at. Fewer than one person in six thought a manual brush's features made their brushing more effective, which is fair, because a manual brush has no features. It cannot tell you that you are pressing too hard, and it cannot tell you when to stop.

Where the 10x comes from

The crossover trial above is a bridging study. Its job was to show that the redesigned Pro brush performs like the sonic brush BURST had already tested, and it concludes that it does. The longer running claim, the one on the box, comes from two thirty day studies run under the American Dental Association's acceptance program requirements for toothbrushes, published as an abstract in the Journal of Dental Research.

Those studies are the source of the four figures BURST prints on the packaging: up to 10x more plaque removed than a manual toothbrush, up to 3x greater reduction in gum bleeding, more plaque removed from between the teeth, and up to 95% greater plaque removal in hard to reach areas.

That last one is the same finding as the crossover study, wearing different clothes. Hard to reach is the whole story. It is why the headline number is large, and it is why the number is honest only if you understand that it describes the crevices rather than the flat enamel you can see.

What the hardware actually is

Bristles	Super soft, multi length, tapered, hygienist specified
Technique feedback	Pressure sensor with real time correction and a post brush score
Timing	Two minute timer with thirty second quadrant guidance
Modes	Five, including sensitive and freshen
Battery	Up to nine months per charge, USB-C
Included	Brush head, charging base, USB-C cable, magnetic wall mount
Head replacement	Every twelve weeks
Developed with	A community of more than 40,000 dental professionals
Customer rating	4.7 out of 5, from 1,084 reviews on burstoralcare.com

What owners say once the novelty wears off

Brush smarter, not harder

The slogan turns out to be a summary of the data rather than a decoration on top of it. The two sites where a sonic brush beats a good manual one by the widest margin are the two sites that pressure cannot open. Soft tapered tips get in there. A heavier hand does not, and over enough years it costs you gum instead.

None of which requires you to think about any of it at six in the morning, which is the actual point. The brush watches the pressure, counts the two minutes, moves you around the four quadrants and gives you a score. You just have to stop pushing.