Verdict
Negative ions? Toothpaste-less brushing? It might sound like something out of the back pages of a comic book, but the ION-Sei’s unique plaque-removing, bacteria-repelling tech seems to do the trick. You’re paying for the tech though, as other fancy features like multiple modes, Bluetooth connectivity, and pressure sensitivity are all absent.
Pros
- Innovative negative ion tech for reducing plaque
- Available in a generous selection of attractive colours
- Superb, durable bristles
Cons
- Requires a leap of faith
- No pressure sensitivity
-
Unique cleaningNegative ions loosen plaque and repel bacteria -
TimerTwo-minute timer with 30-second intervals
Introduction
The Senyai ION-Sei is a sonic toothbrush that stands head and shoulders above the cookie-cutter competition, thanks to its innovative use of negative ions.
It blasts your teeth with negative ions which not only help destabilise and loosen plaque, but also prevent enamel-eroding bacteria from attaching in the first place. Oh, and it doesn’t even require toothpaste to work its magic.
However, with a relatively unknown presence and a price tag of £129.99/$149.99, it falls just shy of impulse buy-to-try territory. So, is it worth it? Here are my thoughts.
Design and accessories
- Looks great
- Comes with a charging dock
Available in a range of attractive colours – including a delightful pastel Sakura Pink, Lake, Moon Grey, and Day White – this is a toothbrush that’s dressed to impress.
And while design is very much subjective, I’m rather drawn to its super-glossy plastic body, with its overly prominent curves and futuristic Matrix-esque font.
Round the back, you’ll find something unique – a long, charcoal-grey strip that feels like a mix between plastic and graphite.
This is the electric conduction handle, which works in turn with a specially-designed head to help produce those all-important ions you’ve heard so much about.
Overall, it makes a confident, visually appealing statement, albeit one that’s a far cry away from the subtle designs offered by toothbrushes in the Sonicare or Oral-B range. But that’s fine by me. It’s a welcome breath of fresh air, especially when sitting firmly in the equally-glossy Micro-USB charging dock (which, while not USB-C, is still better than anything that requires a specific socket).
With two brush heads included (one hard, one soft) and a solid, durable-feeling build, you won’t feel short-changed, although I do have one major niggle. While there is a built-in two-minute timer, the ION-Sei lacks any form of pressure sensitivity indication, so you won’t know if you’re brushing too hard.
Performance
- Excellent brush head
- Very good cleaning
There are two main components in the ION-Sei that work together to let it perform its magic. The first of these works by using a small replaceable battery that’s built into the handle of the toothbrush (and can be replaced easily by removing a small screw). This battery is connected to a titanium dioxide bar that runs throughout the length of the toothbrush, before being exposed at the neck. It’s this exposed section that the toothbrush head slots over.
Before you brush your teeth, you moisten this bar by running water over the brush head. When your fingers grip the rear conductor panel, the wetness creates a closed body circuit that flows from the toothbrush to your mouth. When you brush, a weak current is generated, and negative ions flood into your mouth and across your teeth.
The second piece of this rather clever solution brings us once again to the titanium oxide bar that lies within the brush head. A built-in UV LED light bathes the bar, producing more negative ions, which are then carried into your mouth by water and saliva. But what makes these negative ions so special?
Quite a few things, it turns out. For starters, negative ions are extremely unstable, so they’re desperate to stick to other molecules to stabilise themselves. In this instance, they have plaque firmly set in their sites, attracting them and weakening their attachment to your teeth, making for easier plaque removal when brushing.
In addition, your teeth will be coated with these negative ions during the brushing process, which will naturally repel negatively charged streptococcus mutans and porphyromonas gingivalis bacteria. The former feeds on sugar to erode tooth enamel, while the latter eats away at gums, causing painful recession and tooth loss. It’s all very clever stuff, and clinically proven to boot.
Does all of this fancy negative ion tech work? In my case, yes. During my six-week testing period, I could visibly see a reduction in plaque. While I was also reviewing a few other electric toothbrushes at the same time, there was an overlap period where the ION-Sei was my daily driver, and I can confidently say that my overall dental hygiene felt better.
Even without toothpaste, the post-brush sensation felt refreshingly clean and almost tingly, with a pleasant sensation of polished teeth. Whether this is all due to the ions or the sonic head, I can’t say, but it’s a sensation that I continue to enjoy to this day.
While I initially ditched toothpaste and brushed purely with water as advertised, it felt wrong to leave the bathroom without any minty freshness. This brush can be used with toothpaste, if only for the feeling it leaves.
We also put my trusty dentures through various tests, including beetroot and spinach. The gentler nature of the ION-Sei meant that it removed less physical debris than some rivals, but this will be a bonus to those that hate overly-powerful electric toothbrushes that may cause discomfort or sensitivity. The three intensity levels can be selected by pressing the power button during use, and even the most powerful one felt pleasantly gentle.
The bristles on the included brush heads are also some of the best I’ve ever used. They’re incredibly long, and fine, providing excellent levels of flexibility while remaining firm enough to put in some proper work. They also seem to be much more durable than any others I’ve tested, and I reckon they’ll last considerably longer than many other alternatives.
Battery life is officially stated to be around two to three weeks, which is quite a generous range. In my case, I’d say it lasted about two weeks or just under. It takes quite a long time to charge this brush, so it’s best topped up overnight.
Latest deals
Should you buy it?
You want a more gentle cleaning experience
The excellent head and gentle experience makes this toothbrush a pleasure to use.
You want more modes or a pressure sensor
Standard toothbrushes offer a wider range of cleaning modes and will tell you when you’re pressing too hard.
Final Thoughts
Despite it being an unusual choice, I think many people would enjoy the gentle-yet-tingly brushing experience served up by the ION-Sei. Its scientifically/anecdotally-backed negative ion tech really does appear to reduce plaque and improve dental health, and its brush heads are some of the best I’ve used.
For a similar price, you can get other electric toothbrushes such as the Philips Sonicare 9900 Prestige with pressure-sensitivity feedback, to prevent you from damaging the gums with overly-forceful brushing. You can also get ones with more modes, and other bells and whistles like travel cases, Bluetooth connectivity, and more.
But for many people, those extras are unnecessary padding. If you’re up for trying something a little different, the ION-Sei is just about reasonably priced enough to try out. Check out our Best Electric Toothbrush guide here.
How we test
We test every electric toothbrush we review thoroughly over an extended period of time. We use standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product.
Find out more about how we test in our ethics policy.
Used as our main electric toothbrush for the review period.
Tested to see how well each brush cleans.
Tested to see what real-world battery life is.
You might like…
FAQs
Yes, you can, although it’s not needed and neither is water.
Verdict
Negative ions? Toothpaste-less brushing? It might sound like something out of the back pages of a comic book, but the ION-Sei’s unique plaque-removing, bacteria-repelling tech seems to do the trick. You’re paying for the tech though, as other fancy features like multiple modes, Bluetooth connectivity, and pressure sensitivity are all absent.
Pros
- Innovative negative ion tech for reducing plaque
- Available in a generous selection of attractive colours
- Superb, durable bristles
Cons
- Requires a leap of faith
- No pressure sensitivity
-
Unique cleaningNegative ions loosen plaque and repel bacteria -
TimerTwo-minute timer with 30-second intervals
Introduction
The Senyai ION-Sei is a sonic toothbrush that stands head and shoulders above the cookie-cutter competition, thanks to its innovative use of negative ions.
It blasts your teeth with negative ions which not only help destabilise and loosen plaque, but also prevent enamel-eroding bacteria from attaching in the first place. Oh, and it doesn’t even require toothpaste to work its magic.
However, with a relatively unknown presence and a price tag of £129.99/$149.99, it falls just shy of impulse buy-to-try territory. So, is it worth it? Here are my thoughts.
Design and accessories
- Looks great
- Comes with a charging dock
Available in a range of attractive colours – including a delightful pastel Sakura Pink, Lake, Moon Grey, and Day White – this is a toothbrush that’s dressed to impress.
And while design is very much subjective, I’m rather drawn to its super-glossy plastic body, with its overly prominent curves and futuristic Matrix-esque font.
Round the back, you’ll find something unique – a long, charcoal-grey strip that feels like a mix between plastic and graphite.
This is the electric conduction handle, which works in turn with a specially-designed head to help produce those all-important ions you’ve heard so much about.
Overall, it makes a confident, visually appealing statement, albeit one that’s a far cry away from the subtle designs offered by toothbrushes in the Sonicare or Oral-B range. But that’s fine by me. It’s a welcome breath of fresh air, especially when sitting firmly in the equally-glossy Micro-USB charging dock (which, while not USB-C, is still better than anything that requires a specific socket).
With two brush heads included (one hard, one soft) and a solid, durable-feeling build, you won’t feel short-changed, although I do have one major niggle. While there is a built-in two-minute timer, the ION-Sei lacks any form of pressure sensitivity indication, so you won’t know if you’re brushing too hard.
Performance
- Excellent brush head
- Very good cleaning
There are two main components in the ION-Sei that work together to let it perform its magic. The first of these works by using a small replaceable battery that’s built into the handle of the toothbrush (and can be replaced easily by removing a small screw). This battery is connected to a titanium dioxide bar that runs throughout the length of the toothbrush, before being exposed at the neck. It’s this exposed section that the toothbrush head slots over.
Before you brush your teeth, you moisten this bar by running water over the brush head. When your fingers grip the rear conductor panel, the wetness creates a closed body circuit that flows from the toothbrush to your mouth. When you brush, a weak current is generated, and negative ions flood into your mouth and across your teeth.
The second piece of this rather clever solution brings us once again to the titanium oxide bar that lies within the brush head. A built-in UV LED light bathes the bar, producing more negative ions, which are then carried into your mouth by water and saliva. But what makes these negative ions so special?
Quite a few things, it turns out. For starters, negative ions are extremely unstable, so they’re desperate to stick to other molecules to stabilise themselves. In this instance, they have plaque firmly set in their sites, attracting them and weakening their attachment to your teeth, making for easier plaque removal when brushing.
In addition, your teeth will be coated with these negative ions during the brushing process, which will naturally repel negatively charged streptococcus mutans and porphyromonas gingivalis bacteria. The former feeds on sugar to erode tooth enamel, while the latter eats away at gums, causing painful recession and tooth loss. It’s all very clever stuff, and clinically proven to boot.
Does all of this fancy negative ion tech work? In my case, yes. During my six-week testing period, I could visibly see a reduction in plaque. While I was also reviewing a few other electric toothbrushes at the same time, there was an overlap period where the ION-Sei was my daily driver, and I can confidently say that my overall dental hygiene felt better.
Even without toothpaste, the post-brush sensation felt refreshingly clean and almost tingly, with a pleasant sensation of polished teeth. Whether this is all due to the ions or the sonic head, I can’t say, but it’s a sensation that I continue to enjoy to this day.
While I initially ditched toothpaste and brushed purely with water as advertised, it felt wrong to leave the bathroom without any minty freshness. This brush can be used with toothpaste, if only for the feeling it leaves.
We also put my trusty dentures through various tests, including beetroot and spinach. The gentler nature of the ION-Sei meant that it removed less physical debris than some rivals, but this will be a bonus to those that hate overly-powerful electric toothbrushes that may cause discomfort or sensitivity. The three intensity levels can be selected by pressing the power button during use, and even the most powerful one felt pleasantly gentle.
The bristles on the included brush heads are also some of the best I’ve ever used. They’re incredibly long, and fine, providing excellent levels of flexibility while remaining firm enough to put in some proper work. They also seem to be much more durable than any others I’ve tested, and I reckon they’ll last considerably longer than many other alternatives.
Battery life is officially stated to be around two to three weeks, which is quite a generous range. In my case, I’d say it lasted about two weeks or just under. It takes quite a long time to charge this brush, so it’s best topped up overnight.
Latest deals
Should you buy it?
You want a more gentle cleaning experience
The excellent head and gentle experience makes this toothbrush a pleasure to use.
You want more modes or a pressure sensor
Standard toothbrushes offer a wider range of cleaning modes and will tell you when you’re pressing too hard.
Final Thoughts
Despite it being an unusual choice, I think many people would enjoy the gentle-yet-tingly brushing experience served up by the ION-Sei. Its scientifically/anecdotally-backed negative ion tech really does appear to reduce plaque and improve dental health, and its brush heads are some of the best I’ve used.
For a similar price, you can get other electric toothbrushes such as the Philips Sonicare 9900 Prestige with pressure-sensitivity feedback, to prevent you from damaging the gums with overly-forceful brushing. You can also get ones with more modes, and other bells and whistles like travel cases, Bluetooth connectivity, and more.
But for many people, those extras are unnecessary padding. If you’re up for trying something a little different, the ION-Sei is just about reasonably priced enough to try out. Check out our Best Electric Toothbrush guide here.
How we test
We test every electric toothbrush we review thoroughly over an extended period of time. We use standard tests to compare features properly. We’ll always tell you what we find. We never, ever, accept money to review a product.
Find out more about how we test in our ethics policy.
Used as our main electric toothbrush for the review period.
Tested to see how well each brush cleans.
Tested to see what real-world battery life is.
You might like…
FAQs
Yes, you can, although it’s not needed and neither is water.
