Philips Sonicare Diamondclean 9900 Prestige review: the best electric toothbrush ever?

The Philips Sonicare Diamondclean 9900 Prestige delivers a deep, professional clean that’s powered with AI… here’s our full review

T3 Platinum Award
Philips Sonicare Diamondclean 9900 Prestige review
(Image credit: Beth Girdler-Maslen / T3)
T3 Verdict

With its all-in-one brush head, multiple intensity and cleaning modes, and its AI-powered app, the Philips Sonicare Diamondclean 9900 Prestige might just be the best electric toothbrush on the market. While it comes with an expensive price tag, the Philips Sonicare Diamondclean 9900 Prestige is incredibly advanced, attractive and adaptive. Highly recommend.

Reasons to buy
  • +

    Multiple intensity and cleaning modes

  • +

    Easy-to-use app with personalised guidance and reports

  • +

    Attractive design

Reasons to avoid
  • -

    Expensive

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In T3’s Philips Sonicare Diamondclean 9900 Prestige review, I put this premium electric toothbrush to the test to see if its advanced adaptive features are worth the hefty price tag.

Last year, Philips celebrated its 30th anniversary of its Sonicare technology. With a unique approach to dental care, Philips’ Sonicare electric toothbrushes are designed to clean and whiten teeth, freshen breath, protect gums and improve its users oral health.

Currently sitting at the top of our best electric toothbrush guide is the Philips Sonicare Diamondclean 9900 Prestige and I’ve been intrigued to try it out, especially as someone who has been a manual brusher my whole life. My fiance is a huge fan of his Oral-B iO7 electric toothbrush, so I also wanted to know which is better: Philips Sonicare or Oral-B?

So, does the Philips Sonicare Diamondclean 9900 Prestige live up to the hype? Is it better than manual brushing and its electric toothbrush competitors? And most importantly, will it improve my dental hygiene? Keep reading for my full Philips Sonicare Diamondclean 9900 Prestige review.

Philips Sonicare Diamondclean 9900 Prestige review: Unboxing

The Philips Sonicare Diamondclean 9900 Prestige arrived with the electric toothbrush body, separate brush head, USB-C travel charger, charger base, and a vegan-friendly leather travel case. The version I received came in a pretty champagne colour but it’s also available in black.

The body and head of the Philips Sonicare Diamondclean 9900 Prestige is easy to fit together and the charger and its base slot together simply, although you’ll need to have a charger adapter. I already had one at home but it’s worth keeping this in mind as the Philips Sonicare Diamondclean 9900 Prestige doesn’t come with the adapter plug.

To get started with the Philips Sonicare Diamondclean 9900 Prestige, you’ll need to charge it first. I charged it overnight using the charger and its base although you can charge the toothbrush while it’s inside the travel charger, which is great for on-the-go use and travelling. Once the Philips Sonicare Diamondclean 9900 Prestige is charged, you need to download the Philips Sonicare app and connect it to your toothbrush. This takes a matter of minutes and is easy to do, although you will need to sign up for an account using an email address. Once this is all done, you’re ready to go!

Philips Sonicare Diamondclean 9900 Prestige review

(Image credit: Beth Girdler-Maslen / T3)

Philips Sonicare Diamondclean 9900 Prestige review: Design & app

The Philips Sonicare Diamondclean 9900 Prestige has an all-in-one brush head that works to remove plaque, reduce stains and achieve cleaner, healthier and fresher teeth and gums. The bristles of the brush are petite and come in white, orange and blue colours which focus on different parts of the mouth while brushing.

The body of the Philips Sonicare Diamondclean 9900 Prestige is sleek, compact and has an attractive colour and style. It has the power button with lights underneath it to show the intensity level and battery life. Once you touch the body of the toothbrush, the lights will brighten and it’s ready to go once you turn it on. The design and controls are surprisingly simple yet the entire toothbrush and app is incredibly intelligent.

The Philips Sonicare Diamondclean 9900 Prestige has 5 cleaning modes: clean, deep clean, white+, sensitive and gum health. To choose between the different modes, you need to select this on the app. The Philips Sonicare app (which is free to download) is AI powered and works with the toothbrush to personalise advice for your brushing style, give you progress reports and shows how well you’ve covered each section of your mouth.

The Philips Sonicare Diamondclean 9900 Prestige has SenseIQ technology which senses pressure, motion and coverage in real-time as you brush. SenseIQ will adapt to your brushing style automatically and adjust intensity if you brush too hard or move the brush too much. The noise and feel of the brush indicates this (which I’ll explain below) but you can also view this on the app, too.

Philips Sonicare Diamondclean 9900 Prestige review

(Image credit: Beth Girdler-Maslen / T3)

Philips Sonicare Diamondclean 9900 Prestige review: Performance

After I charged the Philips Sonicare Diamondclean 9900 Prestige and connected it to the app via Bluetooth, I was excited to give it a go. As a manual brusher, I found the vibrations of the brush really intense even on low mode but after a couple of uses, it started to feel more normal. I’d also say to make sure the brush with toothpaste is in your mouth before you turn it on as the vibrations will make the toothpaste fly off… I found that out the hard way!

The Philips Sonicare Diamondclean 9900 Prestige is intelligent on its own and with the app. The brush buzzes and vibrates intensely and it will pause slightly to tell you when to switch to a different part of the mouth. The handle is nice to hold and lightweight so it’s easy to move around the teeth and gums. The brush will also make different noises to indicate when you’re applying too much pressure or if you’re moving it around too much.

I was impressed by the Philips Sonicare Diamondclean 9900 Prestige’s long lasting battery life. After its first initial charge, it lasted for several weeks and the brush beeped at the end of use if it was low in battery. I will say that the charge information was a bit inconsistent in the app. For example, it said it was 80% charged for multiple uses before it dropped down to 66%. It’s not a deal breaker but I would have preferred it to be clearer.

The Philips Sonicare app is probably the most impressive part of the Philips Sonicare Diamondclean 9900 Prestige. The app instructs you where to clean, alerts you to any issues and shows coverage, timing, scrubbing and pressure results. It breaks up your teeth into 6 parts so you focus 20 seconds on each part of the mouth which totals to 2 minutes cleaning time and it will turn itself off when it’s done. If you’ve missed certain parts of your mouth, the app will recommend to go back and continue until you get the right results.

If you don’t want to constantly bring your phone with you while you clean your teeth (which I don’t enjoy at 6 in the morning!), the Philips Sonicare Diamondclean 9900 Prestige works perfectly on its own and it still connects to the app and monitors your results.

If you’re not sure what brush type to choose, check out our comparison guide to electric toothbrush vs manual brushing.

Philips Sonicare Diamondclean 9900 Prestige review

(Image credit: Beth Girdler-Maslen / T3)

Philips Sonicare Diamondclean 9900 Prestige review: Price

The Philips Sonicare Diamondclean 9900 Prestige is £299.99 and is available to buy at Philips and select retailers like Amazon and Boots. £300 for an electric toothbrush is quite expensive, although compared to some of the latest offerings from Oral-B, the Philips Sonicare Diamondclean 9900 Prestige is a bit cheaper.

The Philips Sonicare Diamondclean 9900 Prestige does drop in price during holidays like Black Friday and you can also use Philips discount codes for money off your order.

Philips Sonicare Diamondclean 9900 Prestige review: Verdict

After testing out the Philips Sonicare Diamondclean 9900 Prestige, I’m a complete electric toothbrush convert! I don’t think I’d ever go back to manual brushing as using the Philips Sonicare Diamondclean 9900 Prestige makes my entire mouth feel cleaner, fresher and healthier. Looking at my teeth after using the Philips Sonicare Diamondclean 9900 Prestige, I’ve noticed that they have less stains, plaque yellowing, and I’d honestly say that I think it’s the best electric toothbrush out there right now.

Philips Sonicare Diamondclean 9900 Prestige review: Alternatives to consider

A good alternative is the Philips Sonicare Diamondclean 9000. The predecessor to the Philips Sonicare Diamondclean 9900 Prestige, the 9000 is a powerful clever electric toothbrush that provides a deep and healthy clean. It has a slightly different design than the Philips Sonicare Diamondclean 9900 Prestige and it's cheaper, too.

If you’d prefer a different brand, the Oral-B iO9 is a brilliant choice that looks good, cleans well with its multiple modes and has a good app and interface. It’s pricier than the Philips Sonicare Diamondclean 9900 Prestige and has some odd tracking features but it’s the best Oral-B electric toothbrush we’ve tried.

Bethan Girdler-Maslen
Home Editor

Beth is Home Editor for T3, looking after style, living and wellness. From the comfiest mattresses to what strange things you can cook in an air fryer, Beth covers sleep, yoga, smart home, coffee machines, grooming tools, fragrances, gardening and much more. If it's something that goes in your house, chances are Beth knows about it and has the latest reviews and recommendations! She's also in the know about the latest deals and discount codes from top brands and retailers.

Having always been passionate about writing, she’s written for websites, newspapers and magazines on a variety of topics, from jewellery and culture, to food and telecoms. You can find her work across numerous sites, including Wedding Ideas Magazine, Health & Wellbeing, The Bristol Post, Fashion & Style Directory, TechRadar, CreativeBloq and more. In her spare time, Beth enjoys running, reading, baking and attempting craft projects that will probably end in disaster!