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Oral-B iO Series 4 review: Oral-B’s best tech on a budget

Our Rating :
Price when reviewed : £240

The most affordable iO-series toothbrush is brilliant at cleaning and offers excellent value, too


  • Superb cleaning power
  • Quiet, comfortable brushing
  • Effective use of LED ring and pulses


  • No fast charging
  • Brush heads are expensive

There’s a lot to love about Oral-B’s iO series of brushes. The magnetic motor at the heart of the technology makes the range significantly quieter than the brand’s older Pro and Genius series brushes, with a superb cleaning action that delivers great results. Oral-B’s smart toothbrush features are still the best in the business, and you’re not short of brushing modes or different toothbrush heads if you plump for an iO-series brush.

Yet there’s just one problem: iO brushes have generally been expensive, with the iO Series 6 coming in at anywhere between £120 and £300, while the flagship iO Series 10 can cost as much as £800. This is the reason the Series 4 is so crucial for Oral-B: it’s the first iO brush you can consistently find for under £100, which is the absolute limit of what many people are prepared to spend on an electric toothbrush.

Oral-B iO Series 4 review: What do you get for the money?

Oral-B’s cheapest iO brush uses the same magnetic drive as the more expensive iO brushes, combining a rotary brush head that oscillates clockwise and anti-clockwise with micro-vibrations designed to loosen up plaque and boost its removal. The basic design of the brush is also much the same, with a slim, cylindrical handle that tapers off towards the brush head, an LED indicator at the join between the handle and the head, and an iO-series head at the top. The iO Series 4 is compatible with all iO brush heads, so you can switch from the default Ultimate Clean head to the softer Gentle Care head or the whitening Radiant White, if you so wish.

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The biggest difference between the Series 4 and the Series 6 and above is that the entry-level model lacks the higher-end versions’ OLED display. In fact, there’s nothing between the power button and the button below that toggles between the brush’s four modes: Daily Clean, Whitening, Sensitive and Super Sensitive. The Series 4 doesn’t have the 3D tracking features of the Series 9 and Series 10 models, which record where in your mouth you’ve brushed, and it only comes with a basic 2-pin Oral-B charger rather than the fast magnetic charger of the Series 7 and above. Oral-B also bundles in a basic plastic travel case and a semi-transparent case that can house two heads.

The Series 4 is available in three colours – white, a light lavender purple and black – but the heads are only available in black or white.

Oral-B iO Series 4 review: What’s it like to use?

Where the Series 6 and the higher-end iO brushes can give you instant feedback on your brushing through the OLED screen, the Series 4 has to rely on the colour-changing RGB LED ring indicator on the grip and more conventional pulse indicators for timing. This isn’t really a problem. The pulses indicate when you’ve reached 30 seconds, at which point you move on to the next quadrant of your mouth, while the LED ring cycles through a range of colours to “celebrate” when you’ve reached the end of your two-minute brush.

It’s possible to set the default colour of the indicator in the smartphone app – handy, if you have multiple iO brushes in the bathroom – while the pressure sensor makes its transition between blue, green and red, depending on whether you’re brushing too softly, brushing too firmly, or getting the pressure just right.

Once installed, the app connects to your brush in a jiffy and reconnects without any hassle most of the time, although I had a couple of sessions where I had to restart the app and press the on/off button before the toothbrush would connect. The app itself is well laid out and mostly intuitive, monitoring each toothbrush to see how long you brush for and how much pressure you apply, then giving you tips on how to improve your technique. It also tracks your brushing over days, weeks and months, and has some more general dental advice that you might want to build into your routine. The brush will sync with the app and share info if you haven’t used it for a few days, so you don’t need to take your phone to the bathroom every time you brush your teeth.

Oral-B iO Series 4 review: How well does it clean?

The best reason to buy an iO-series brush was never the display or the smartphone features, but the whole experience feels like a big step on from Oral-B’s previous brushes. The Pro and Genius brushes do a fantastic job of cleaning your teeth, but they can be noisy and create a level of vibration in the hand and in the skull that some people find hard to deal with. Philips’ Sonicare brushes have generally been quieter and easier to live with. The iO tech changes that; you can still have a really powerful brush and an intense deep clean, but without the racket.

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The iO Series 4 repeats this trick, and I’m not sure you can get a better clean from any toothbrush, no matter how much you spend. There are Sensitive and Whitening modes to tackle more specific needs, but I found that the Daily Clean did a fantastic job of clearing debris and plaque on and in between the teeth, leaving them feeling smooth and polished. The iO-series brush heads are larger than the standard Oral-B heads, and some people will find a Sonicare brush or Pro-series Oral-B brush a little more comfortable. Nevertheless, the iO Series 4 – like every other iO-series brush – delivers excellent and highly effective cleaning.

Oral-B iO Series 4 review: How long does the battery last?

Running repeated brushing cycles on the Series 4, the batteries drained after 1hr 38mins. Brushing twice a day for two minutes, you’re looking at roughly three-and-a-half weeks before you need a recharge. That’s not bad at all, although we’ve seen some Sonic brushes that can keep running for well over a month. Forget about fast charging, though. With the charger supplied, it’s best to charge the toothbrush overnight.

Oral-B iO Series 4 review: Should I buy it?

This still isn’t a cheap brush, but it’s a more accessible and affordable iO brush without any major compromises. While you don’t get the screen or the full range of modes or extra features, you still get the same superb technology. True, you have to factor in the price of brush heads – and iO-series heads are still among the most expensive, costing upwards of £20 for two or £30 for four, although there may be some cheaper deals to be had. But if you want the best brush you can buy without spending over £100, this is arguably the best one out there.

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