Philips Sonicare DiamondClean Smart 9750 Review: high-tech brushing that feels a bit overkill

I’ve been using Philips Sonicare brushes for a while, but the DiamondClean Smart 9750 is the most expensive one I’ve tried. I picked it up mostly out of curiosity: I wanted to see if all the “smart” stuff (app, sensors, brush head detection) actually changes anything day to day, or if it’s just a fancy way to charge more. I used it as my only toothbrush for a few weeks, morning and night, to get a proper feel for it.

Right away, it’s clear this is not aimed at someone just looking for a cheap electric brush. The price is high, the box feels premium, and there’s a bit of that “gadget” vibe when you first open it. You get multiple brush heads, different modes, an app to install, and a handle that vibrates much more strongly than any basic electric brush I’ve used before. So you don’t just plug and brush, you kind of have to set it up like a device.

In daily use, I focused on a few things: how clean my teeth actually felt, how annoying (or useful) the app and sensors were, how often I had to charge it, and whether the build quality felt good enough for the price. I also paid attention to comfort, because some Sonicare models can feel a bit harsh on sensitive gums if you go full blast. I mixed up the modes and intensities to see what actually matters and what’s just marketing on the box.

Overall, it does clean really well and the tech features are not pure gimmick, but it’s definitely not perfect. For this kind of money, I expect something that feels rock solid and lasts many years. Between my own impressions and the reviews mentioning mechanical failures after a few months or years, I’d say it’s a strong performer with a question mark on long-term durability and whether the extra smart features really justify the extra cost for most people.

Let’s be blunt: this toothbrush is expensive. You’re paying for a mix of strong cleaning performance, premium design, multiple brush heads, and a lot of smart features. The question is whether all of that is worth the extra money over a mid-range Sonicare or even a simpler electric brush. For most people, I’d say it depends on how much you care about the app and the fancy extras versus just getting a good clean.

In terms of pure cleaning, you can get close to this performance with cheaper Sonicare models that have fewer modes and no app. The 9750 does add comfort touches like brush head detection, pressure sensor, and nicer accessories, but those don’t necessarily translate into twice the real-world benefit compared to something half the price. You also have to factor in the cost of replacement heads, which are not cheap either, especially the premium ones included here.

Where the value improves is if you actually use the smart features to fix bad brushing habits. If the app coaching keeps you from skipping areas and the pressure sensor stops you from wrecking your gums, that can save you money at the dentist in the long run. Also, Philips support seems fairly responsive based on several reviews, which helps a bit with the overall value if something breaks during or just after warranty.

Still, if you’re on a budget or just don’t care about Bluetooth in your toothbrush, there are better deals in the Sonicare range. I’d call the DiamondClean Smart 9750 a good product at a high price, not a bargain. It makes more sense for someone who likes tech, wants top-tier features, and is okay paying extra for small quality-of-life improvements and a nicer look on the bathroom counter.

The DiamondClean Smart 9750 in Lunar Blue looks nice on the sink, no question. The finish is matte, the color is a bit more interesting than the usual white, and the handle has a slim, modern shape. The button layout is simple: one main power button and a secondary button for mode selection. You also have small icons for the modes and an illuminated ring near the bottom that acts as a pressure warning. Compared to older Sonicare handles I’ve used, this one feels more polished visually and less “medical device”.

In the hand, it’s fairly comfortable. The handle is not too heavy, and the shape is easy to grip even with wet hands. That said, the surface is more smooth than grippy. It looks nice but can feel slightly slippery if you have toothpaste foam and water all over your hand. I would have preferred a bit more rubberized texture on the back or sides, especially at this price. The buttons are easy to press, but once your hands are soapy, you sometimes have to wipe it quickly to change modes without mis-pressing.

The charging setup (often a charging glass or premium base, depending on the exact bundle) looks good on the counter, but it also screams “expensive accessory”. It’s the kind of thing you don’t want to drop. It does make it easy to just drop the brush in and let it charge, though, and it avoids ugly plastic cradles. For travel, the included case is practical: it keeps the handle and a couple of heads in one place and feels sturdy enough for a suitcase. Some versions let you charge through the case with USB, which is handy if you travel a lot.

Design-wise, I’d say it’s visually well done and feels premium in the short term. But when I read that some users had internal mechanical failures (loose internal parts, vibration mechanism going weak, moisture issues), it makes me a bit cautious. The outside looks and feels high-end, but the long-term durability of the internal design seems like a potential weak point. For something this pricey, I’d trade a bit of sleekness for a more rugged, sealed, “this will last 5–7 years” feeling.

Battery life on this thing is pretty solid. Philips claims “weeks” of use, and that lines up with what I saw and what some other users report. With twice-a-day brushing on medium intensity, I got a bit over two weeks before it started to dip. One Amazon reviewer mentioned going at least 8 days without charging and it was still going, which sounds consistent. You don’t need to park it on the charger every night, which is nice if you like a cleaner-looking sink.

Charging is simple: you place it on the charging base (or in the charging glass, depending on your version) and leave it there. It’s not fast-charge or anything, but it’s also not something you charge daily, so I don’t really care if it takes a few hours to fill up. For travel, you can easily go on a week-long trip without the charger if you start with a full battery. If you’re going longer, just throw the charger or USB travel case in your bag and you’re covered.

The only concern I have around battery is not the battery life itself, but what some users mention about moisture getting into the handle over time and causing issues with the electronics and battery contacts. That’s not something I’ve hit yet, but I’ve seen complaints about sudden power drops or the brush dying completely after a year or two, often linked to internal corrosion. So while the battery life per charge is good, long-term battery reliability seems tied to the overall sealing and build quality.

Overall, for day-to-day use, the battery is one of the things you don’t really have to think about. Charge it every couple of weeks, or just keep it on the stand if you’re lazy, and you’re fine. It’s not a reason to buy it by itself, but it’s definitely not a weak point in normal use either.

In the mouth, the DiamondClean Smart 9750 is clearly stronger than basic electric brushes. Philips claims 62,000 bristle movements per minute, and you do feel that. On the standard Clean mode at medium intensity, it’s a strong but manageable vibration. On the highest intensity with Deep Clean+, it’s pretty aggressive, especially if you’re not used to Sonicare-style brushing. My gums tingled the first few days when I pushed the intensity too high, so I ended up using medium or low most of the time.

The brush heads included are on the softer side in terms of bristle feel, which helps. They’re labeled as soft, and I’d agree. They don’t scrape or feel harsh, even when you press a bit too much. Where comfort can drop is with the noise and vibration in the skull: like all SoniCare models, there’s a bit of that buzzing in your head effect. It’s not painful, just a bit tiring if you’re sensitive. After a week, I got used to it, but if you’re coming from a very gentle oscillating brush, the first impression might be “whoa, this is intense”.

The built-in pressure sensor is actually useful for comfort. When you push too hard, the light ring flashes and the brush tone changes slightly, so you know to ease off. I noticed I was pressing more than I thought, especially on the front teeth. After a few days, I adjusted my grip and angle, and the sensor hardly triggered anymore. This helps protect your gums and enamel and makes the brushing experience less irritating over time.

Day to day, the brush is easy enough to live with. You turn it on, it runs a timed cycle (2 minutes or more depending on the mode), and it pauses slightly every 30 seconds to tell you to move to the next quadrant. If you hate timers, that might annoy you, but for me it’s helpful to not rush. Overall, comfort is good once you find your preferred mode and intensity. Just don’t expect a super gentle spa-like feeling out of the box; it’s more on the powerful side, and you need a few days to dial it in.

This is where things get a bit tricky. For a brush that costs this much, you expect it to last several years without drama. My time with it so far hasn’t been long enough to kill it, but between my past experience with Sonicare and the Amazon reviews, I’m cautious. One user mentioned their first handle lasted around three years before the “wiggly bit” got loose and stopped working properly. Their second one died after just three months with the same kind of mechanical failure, where the head rattles but doesn’t vibrate effectively.

Other complaints point to moisture getting inside the handle, damaging the electronics or battery contacts. Once that happens, you can see things like weaker vibrations, weird noise, or complete failure to turn on. Some people also mention loose screws inside the oscillator mechanism, which cause extra noise and poor vibration transfer. For a device that spends its entire life near water and toothpaste, the sealing and internal construction really need to be solid, and it sounds like that’s not always the case.

To be fair, Philips support seems decent when things go wrong. Several reviews mention getting a replacement even slightly out of warranty, usually within about a week once they send proof. That’s good, but it doesn’t fully fix the annoyance of a $300+ brush dying after a year or so. You don’t buy at this price expecting to play the warranty lottery. At this level, I’d want something that feels built like a tank, not something where I’m already thinking “hope this one doesn’t get water inside”.

So in terms of durability, I’d rate it as acceptable but not reassuring, especially given the cost. If you’re gentle with your stuff, don’t leave it soaking wet, and avoid dropping it, you’ll probably get a few years out of it. But based on user stories, there’s a non-zero chance of mechanical or moisture-related failure earlier than you’d like, and that’s the main thing holding me back from fully recommending it without hesitation.

Performance-wise, the brush is strong and consistent. The motor doesn’t bog down when you press lightly against the teeth, and the different modes actually feel distinct. Clean is your standard daily mode, White+ adds a bit more intensity and a slightly longer cycle, Gum Health feels a bit gentler and more pulsy, Deep Clean+ is the long intense one, and Tongue Care is short and soft. After some trial and error, I mostly stuck to Clean for mornings and Deep Clean+ on medium intensity at night, with Tongue Care when I remembered.

The smart features are where this model tries to justify its price. Brush head detection (BrushSync) is neat: you pop on a different head and the handle switches modes automatically. That’s convenient if you regularly swap between, say, an all-in-one head and a plaque control head. Realistically, most people will probably use one type of head until it wears out, so the automatic mode switching is nice but not essential. The pressure sensor, on the other hand, is genuinely helpful and not just a gimmick. It directly improves how you brush.

The app is the most “extra” part. It gives you real-time coverage tracking, tells you where you missed, and logs your sessions. It’s good for the first week or two to fix habits, but after that I found it annoying to always bring my phone into the bathroom. Bluetooth pairing was mostly fine, but occasionally it wouldn’t connect instantly, and I’m not going to stand there with a toothbrush in my mouth fiddling with my phone. So in practice, the app became an occasional check-in tool rather than a daily companion.

If you like data and coaching, you’ll probably enjoy the app and smart features more than I did. If you just want a powerful toothbrush that works every day, you can basically ignore half the features and still get 90% of the benefit. That’s the main thing: the raw brushing performance is strong; the smart stuff is a bonus, not a necessity, and some of it feels like overkill for a bathroom device.

Out of the box, the Philips Sonicare DiamondClean Smart 9750 looks like a full kit, not just a single brush. You get the main handle, multiple brush heads (including an A3 Premium All-in-One and a C3 Premium Plaque Control), a charging solution, and usually a travel case. The exact combo can vary by region, but the idea is: one handle, several high-end brush heads, and a premium charging setup. Compared to cheaper Sonicare models that come with one head and a simple charger, this feels more like a bundle than a basic starter pack.

The handle has 5 brushing modes: Clean, White+, Gum Health, Deep Clean+ and Tongue Care. On top of that, you get 3 intensity levels, so in theory you can fine-tune things a lot. There’s also brush head detection, which means when you snap on a specific head, the brush automatically picks a recommended mode. In practice, that’s convenient the first few days because you don’t have to remember which head is for what, but after a while you’ll likely just stick to one or two modes anyway.

The other big thing is the app connection. You pair the handle with the Philips Sonicare app on your phone. The app tracks your brushing, shows where you’ve missed spots, and nags you (in a good way) if you rush through areas. I tried it seriously for about a week, phone on the sink, Bluetooth on. It works, but it also adds friction: you have to open the app, wait for pairing, etc. After the novelty wore off, I mostly brushed without the app and only synced once in a while.

So overall, presentation-wise, it’s clearly pitched as a high-end, techy toothbrush: multiple heads, smart detection, app, sensors, modes. If you like gadgets and want to tinker with settings, you’ll have plenty to play with. If you just want something that vibrates and cleans, a lot of this might feel like extra stuff you didn’t really need but paid for anyway.

Let’s talk about the main point: does this thing actually clean better than a regular brush or a cheaper electric one? In my experience, yes, it does a very solid job. After a full cycle on Clean or Deep Clean+, my teeth feel smooth when I run my tongue over them, especially around the gumline and between teeth. Plaque buildup on the lower front teeth (where I usually notice it first) was noticeably less after about a week of consistent use compared to my older, more basic Sonicare model.

I don’t have lab data to confirm the “20x more plaque removal” or “100% more stains” claims, but I can say this: coffee stains on my front teeth faded a bit after using White+ mode daily for about 10 days. It’s not like getting them professionally whitened, but the color looked slightly more even. The Tongue Care mode is also actually useful if you care about breath; it’s shorter and gentler, and the vibration pattern feels better for the tongue than just using the normal mode.

Where the toothbrush really pushes effectiveness is with the app and mapping. When I used the app seriously, I realized I was consistently under-brushing the back molars and the inside surfaces. The app nags you when you move on too fast, which forces you to slow down and cover every area. After a few days of following that guidance, my brushing got more even, and I stopped seeing those little yellow patches on the usual problem spots. Once those habits stick, you don’t strictly need the app every time, but it’s useful as a training tool.

So in practice, effectiveness is strong: my mouth feels cleaner, my gums looked less red in some areas, and food residue between teeth after meals seemed easier to remove when I brushed in the evening. Is it miles better than a mid-range Sonicare if you already brush properly? Probably not miles, but there is an improvement, especially if your technique was a bit sloppy before. For someone upgrading from manual, the jump in cleanliness will feel very big.