The Prestige 9900 is an impressive toothbrush. It is the best smart toothbrush on the market today.
It cleans the teeth well. It looks great and feels premium in the hand. It has the essential features you need.
In our post on the best Sonicare toothbrush, we rate it as the best top of the range model.
It also has lots of extra technology too. For example, real-time tracking and personalized feedback. It can help you brush your teeth better, and improve your oral care habits, if you are keen to do so.
Sonicare have done a great job of simplifying the whole ‘smart toothbrush’ experience.
As much as I like this brush, the fact remains that you don’t need a toothbrush this capable or expensive. There are much more affordable options that clean the teeth as well.
- Premium handle that looks and feels good
- Timer and pacer encourage brushing for the recommended time
- Visible pressure sensor alerts you when you are brushing with too much force
- BrushSync technology reminds you when to replace your brush head
- Long battery life between charges
- Bluetooth & AI technology works well – Sonicare have simplified the user experience
- Stylish and compact travel case – you can even charge the toothbrush whilst inside
- Better value options exist (see other choices)
- There is no place to store the detachable USB cable for the travel case
- Bluetooth connectivity isn’t essential
Consider these other brushes
If I were buying a new electric toothbrush today, my choice would be the Oral-B Smart 1500.
It’s affordable with the features you need. It is our number 1 choice for the best electric toothbrush.
The Prestige 9900 is excellent. It is one to pick if you want the most capable Sonicare toothbrush with additional features.
Albeit an older model, the DiamondClean Smart is still a great choice and might well be a better value buy.
Honestly, the Smart 1500 from Oral-B cleans your teeth as well though. All brushes require you to use the correct technique.
If you particularly want a great value sonic toothbrush, the 4100 Series would be my pick.
Our guide to taking care of your teeth shows you all of the important things you need to know, irrespective of the toothbrush you use.
Sonicare 9900 Prestige in depth review
Sonicare are a brand that continually innovates. As they improve products, they
look at how features and functions can be added to really benefit the user.
The 9900 is perhaps one of the best examples of this. They are innovating by simplifying.
By trying to take away some of the complexities, it makes it easier for you and I to just get on and use the product. But, the value added extras are present if we require them.
Variants of this toothbrush
There are 3 variants of the Sonicare 9900 Prestige.
The difference is the color of the brush handle and travel case.
From a feature, performance and technical point of view they are all the same.
The colors and model numbers are as follows:
- Champagne – HX9990/11
- Midnight Blue – HX990/12
- Pink – HX9990/13
The travel case is color matched to the brush handle.
The pink and champagne models come with white USB cables/power adapters and brush head. The midnight blue option comes with a black brush head, USB cable and power adapter.
Sonicare has also added a limited edition variant of the 9900 Prestige to the range.
The ‘Limited Edition Pink’ variant is technically identical to the other variants of the Prestige. The difference is the brush comes with 2 x A3 brush heads included and printed on the travel case is a blossom tree design.
The new variant is model number HX9990/31.
What’s in the box?
- 1 x Sonicare 9900 Prestige power toothbrush
- 1 x A3 Premium All-in-One brush head (with plastic cover)
- 1 x Travel case
- 1 x USB-A to USB-C cable
- 1 x USB power adapter
- 1 x Charging base (made up of 2 parts)
- USB powered base plate
- Frosted plastic frame known as the ‘puck’ (sits on top of power base for a more secure hold of the handle and premium look)
- 5 cleaning modes
- Built-in timer and pacer
- Visible pressure sensor
- Visible scrubbing sensor
- 14+ day battery life
- Automatic power off
- Brush head replacement reminder system
- Real-time tracking of the brush head position
Design, usability, clean & general use
If you are not already familiar with Sonicare toothbrushes, they are quite distinctive. There are design elements that are consistent across the range.
In my experience, the Philips electric brushes generally look and feel more premium. As the name implies, the Prestige is no exception.
The 9900 is available in 3 color options, midnight blue, champagne and pink.
The box contents is the same for all 3 variants. The difference is purely the color of the handle and the accessories that are included.
I have the midnight blue and champagne colored versions.
As with any toothbrush, there are 2 key parts, the brush handle and the brush head.
Both are important. They work together to achieve some great cleaning results.
With the introduction of the 9900 comes a new simplified design to the brush handle. There is to the new A3 Premium All-in-One brush head. This too has been designed to make brush head choice easier.
The 9900 is a very capable toothbrush. Clever and smart features don’t necessarily make it a better toothbrush though. These capabilities can make it overwhelming and complicated for users. This is why then that simplification is a theme that runs throughout the Prestige. I will explain how throughout this review.
Slide off the outer cardboard sleeve to reveal another box. Open the lid like a book to reveal the 9900 and accessories inside.
The handle and case are protected with a plastic sleeve made from CPE Type 7 plastic. The brush head, power adapter and charging plate are wrapped in LDPE 4 plastic. I am not sure this is really necessary?
You get a useful quick start guide as well as some other regulatory documentation.
The handle of the brush itself is pretty typical for an electric toothbrush. It measures 17.5cm (6.9 inches) tall (without the brush head) and 2.7cm (1.1 inches) wide and 2.8cm (1.1 inches) deep. Fit the head and it is 24cm (9.4 inches) tall.
It has a rounded design to it. It is not a perfect cylinder, nor is it completely square. There is a gentle curvature and a slight squaring to the sides. This offers a secure and comfortable in hand grip.
On the front of the handle you will find just 1 obvious button. This is the power button. It is placed in the upper third of the brush handle with the Philips Sonicare logo just above it.
The button has a concave design and a power icon printed on it.
One fairly major change from many other models is that the power button has a ‘seamless’ design. This means that there is no physical gap between the button and the rest of the handle.
Most other Sonicare models have a very small gap between the button and body of the toothbrush handle. This is typical of a lot of power buttons on products. But, the problem has been that gunk and grime from brushing (dried toothpaste) has seeped into this gap. In turn, this has caused usability and durability issues. Whilst toothpaste residue will still drip down the handle. No longer should this build up around the power button to cause usability issues.
Unlike many buttons, this is a touch/pressure sensitive button. You press it, and the brush turns on. I don’t dislike it. But you don’t get that same reassuring click or resistive feedback as you might with many other buttons.
The button itself is finished in the same matt coating as the rest of the handle. It does not have a rubberized coating or anything to make it particularly grippy. Rubber coated buttons tend to be found on the more cost effective brushes.
There is too no backlight to the power button.
Beneath the power button are 3 dots, stacked on top of each other.
These are the LEDs for the intensity settings the brush offers.
The intensity LEDs are normally oriented horizontally. This is a design change for the Prestige 9900.
The 3 intensities are low, medium and high.
Rather neat is the size of the dots are different. The top one is the largest with the next being slightly smaller and the bottom one being the smallest. This is a nice link to the intensity levels. The larger the dot, the greater the intensity.
The number of lights lit, reflects the intensity, or power of the toothbrush.
- 1 light – low intensity
- 2 lights – medium intensity
- 3 lights – high intensity
High intensity is the most powerful, but different cleaning modes use different amounts of power from the brush motor. The intensity will be higher on the standard Clean mode compared to Gum Care for example.
Normally the intensity is changed by pressing a separate mode button.
But with the Prestige, you simply press on the 3 dots. The intensity icons are essentially a button themselves. It functions like the power button in that you get no resistive or clicky feedback. You will see the LEDs changing and feel the handle vibrate. Keep pressing the button until you have selected the intensity you desire.
You can also change the intensity from the smartphone application
Below these LEDs sits the SenseIQ logo. This lights up too. I will explain precisely what SenseIQ is shortly.
In the lower half of the brush handle, toward the very bottom is the battery status icon.
This will pulse white when the toothbrush is on charge. It will also light up after each use to offer some insight into the battery power remaining.
I cover the battery in more detail within the ‘battery life’ section of this review. The key thing to note is that you should get at least 2 weeks of use from the built-in rechargeable Lithium-Ion battery.
Just above the battery icon, sits the brush head replacement reminder icon. It is barely noticeable unless it is lit. But, it is not lit all that often.
This reminder system is 1 of 2 parts that make up BrushSync technology. The other part is mode pairing.
The majority of Sonicare brush heads have a radio-frequency identification (RFID) chip built-in. This includes the provided A3 Premium All-in-One brush head.
The chip is detected by the handle, when the head is fitted. The handle then logs how often and for how long the head has been used.
Our own research has shown that 4 in 10 people do not change their brush head every 3 months. And a quarter of people only change their brush head every 6 months.
Using the brush head for longer than 3 months can mean that the brush head is cleaning less effectively. Worn and frayed bristles could also be doing damage to the teeth and gums.
This is where the brush head replacement reminder comes in.
Once the handle has tracked that the head has been used for 3 months, the reminder icon will be lit an amber color. This is your visual clue to replace the head.
For those wondering, it is smarter than simply tracking the date the head was fitted. If you brush for 3 minutes, 3 times a day, the reminder will be lit sooner than someone who brushes twice a day for 2 minutes.
The light will remain lit until the head is replaced or the reminder feature is disabled.
This is a system exclusive to Sonicare toothbrushes.
The 2nd part of BrushSync technology is mode pairing. As the name implies, the brushing mode is changed automatically, to best suit the brush head attached. That is providing the handle has the appropriate cleaning mode.
It should be noted that mode pairing doesn’t actually apply to the 9900. This is due to the way the cleaning modes are enabled and disabled.
Normally on the lower half of the brush handle, you will find labels for the cleaning modes available. It is too quite common on premium models, to have a separate button to change/cycle between these modes. This does not apply on the Prestige.
This is all to do with the simplification of use that Philips are looking to achieve.
The reality is you don’t need lots of different cleaning modes.
There is rarely much difference between them and the results each mode offers. A whitening mode is rarely actually going to make your teeth whiter, despite what many think.
The slight exception is a sensitive/gum care mode. These tend to be less powerful and offer a more gentle brushing experience. With the Prestige you just need to change the intensity from high to low for that more gentle brushing.
Feedback from readers of this site would imply most stick to using just 1 mode most of the time.
Sonicare’s own research has shown that most users are confused by which mode to select.
This is why then just 1 mode, ‘Clean’ is enabled on the brush handle.
You do have an additional 4 cleaning modes but they are not available on the handle itself. You need to enable these in the app.
The 5 brushing mode options you have are:
- 2 minutes
- 2 minutes and 40 seconds
- Gum Health
- 3 minutes and 20 seconds
- Deep Clean
- 3 minutes
- 2 minutes
Clean is the default mode.
You can enable any of the other modes, from the smartphone application. But, only 1 mode can be active on the handle at any one time.
You can’t enable them all and switch between them with just a tap.
To change the mode you need to go into the app, change the mode and then let the handle update.
It does make it more awkward for those who like to change modes. It is because of this approach that the BrushSync mode pairing does not function.
Our Sonicare cleaning modes article explains the differences between each mode in detail.
In conjunction with the change the cleaning modes, is the introduction of a new brush head. It is named the A3 Premium All-in-One.
This head has been engineered to be effective at removing plaque, help whiten the teeth and be kind to the gums too. It does away with the need for different brush heads. More on these shortly.
On the very bottom edge of the brush handle is a light ring. You can barely notice it unless a light shines from it. This is not a customizable light right, like you get on the likes of the Oral-B iO. Instead, either a purple or yellow light will emerge. The color depends on whether the pressure or scrubbing sensor has been activated.
The base of the brush handle is flat, with some regulatory information printed on it. There is no recess into which a charging pin on the charging stand would fit. There is no need to physically connect a cable to the toothbrush either. The Prestige uses the same wireless charging like other brushes. The difference is that the stand is configured differently.
The sides are free of ports and controls as is the rear of the handle. There is a lack of raised gripping points. This is good because it helps retain the slick and premium design. But it is also a bit of a negative. Some extra ridges on the rear would give the fingertips a little extra surface to grip onto. That said, many Sonicare models are designed like this and I haven’t found it to be a big issue.
When laid flat on its back, it doesn’t roll all that easy. It can roll onto its side. But, the balance of the weight and the shape means it doesn’t actually roll away. The bristles of the brush head shouldn’t make contact with the countertop either.
At the top of the brush handle is where the brush head attaches. It clips onto the metal shaft that extends from the motor located inside.
The Prestige 9900 is not as tall as the DiamondClean Smart. In fact, it is 18mm smaller. It is also not as thick. Given the extra features in this brush, this is good to see.
When fitted, there is a very small gap between the brush head and the brush handle. This is normal. If you look at the head side on, you will also see that it is angled ever so slightly. This is all to help with reach when brushing, particularly at the back of the mouth.
At the top of the handle, just below the fitted brush head there is a gold colored plastic ring. It wraps around the top of the handle. It gives a slight design accent to the toothbrush, which I like. This gold accent is consistent with the travel case and charging stand too.
The head supplied with the champagne and pink variants are white. The head supplied with the midnight blue mode is black. It is a slight contrast in color to the handle itself.
Sealed inside the brush handle is the rechargeable battery and other electronics required.
The handle is water resistant, which means a rinse under the tap is absolutely fine. Sonicare doesn’t state whether you can use in the shower or not. Do not use in the bath though. You don’t want the brush to become submerged.
The motor inside is a sonic motor that causes the bristles of the brush heads to move in a side to side sweeping action.
31,000 brush strokes or 62,000 movements per minute is what you get from the Prestige. This is the same as almost all other Sonicare toothbrushes.
To explain this further you would count 1 movement as the bristles moving from the top to the bottom of the tooth. Imagine a pause, the 2nd movement would be from the bottom back to the top.
A single brush stroke is the bristles moving top, to bottom and back again.
I wanted to make this point as often movements are quoted and perceived to be more powerful or better. The reality is this is not the case. It is just another way to describe the same thing.
Whether you get that full power (31,000 brush strokes) depends on the cleaning mode selected. Some modes do not use the full power of the brush.
When powered on the brush does produce a sound. It is not silent. This is typical of a sonic toothbrush. An audible humming sound. It measures in at 71 decibels. It is quieter than the likes of the Oral-B brushes that have a much more mechanical sound.
As you power on the toothbrush, you activate the 2 minute timer and pacer.
The general recommendation is to brush the teeth twice a day for 2 minutes. And during this 2 minute clean you should aim to brush the teeth as evenly as possible. It is no good brushing just the front teeth.
This is where the timer and pacer come in. They help you with this. These are one of the most essential features of electric toothbrushes. Brushing for the right amount of time and using the correct technique will improve your oral health.
Typically, it is advised to break the mouth up into 4 sections, upper right, upper left, lower right and lower left. The idea is 30 seconds are spent on each section of the mouth. After 2 minutes the result will be a fairly even clean across all teeth.
Sonicare have implemented this slightly differently. On the 9900 Prestige, they have set the pacer at 20 second intervals.
This results in 6 sections of the mouth to brush.
- 1 – Upper right back teeth
- 2 – Upper front teeth
- 3 – Upper left back teeth
- 4 – Lower left back teeth
- 5 – Lower front teeth
- 6 – Lower right back teeth
The 6 sections of 20 seconds intervals still result in the same brushing time. It is just a slightly different approach.
As you clean each section, you need to make sure you brush the front, back and top surfaces of the teeth.
Doing this should help ensure all teeth get an even clean and you help maintain your smile.
At the end of the 2 minutes, the toothbrush automatically turns itself off. This is a very obvious sign that the required brushing time has passed.
If you want to brush for longer, you can. You will just need to turn the toothbrush on again.
Different cleaning modes on the 9900 last longer than the standard 2 minutes. As a consequence, the pacer and sections to focus on change. The image below gives more information on the approach to use. Be sure to become familiar with these, to get the best results.
During any cleaning mode, a number of different sensors are active on the Prestige 9900.
Most notable are the pressure sensor and scrubbing sensor.
The pressure sensor alerts you when you are brushing with too much force.
Brushing harder does not equal a better clean. Excessive pressure can be damaging to the teeth and gums.
The Prestige alerts you in 2 different ways. It will vibrate the handle with a particular vibration pattern. But it will also make the light ring at the bottom of the brush handle flash with a purple light. Both of these will remain active until the pressure is reduced.
Only the DiamondClean Smart and the 9900 Prestige have a visible pressure sensor.
A visible sensor is much more common on Oral-B models.
If you are using the smartphone application at the same time, it will alert you on screen too.
When the pressure sensor is activated so too is the adaptive intensity technology.
What this does is reduce the intensity of the brush motor if the pressure sensor is active for more than 5 seconds.
For example, your brushing intensity is set to high. You brush your teeth and apply too much pressure. As you do the brush handle will begin vibrating and the pressure sensor light will flash. If this continues for 5 seconds, the intensity will drop to medium.
If it continues for another 5 it will drop to the lowest intensity.
The intensity will remain low for the rest of that cleaning mode, even if you relieve the pressure. You can alter it manually if you like.
This adaptive intensity can be turned off within the app if you would rather.
The Prestige is the first Sonicare to also have a scrubbing sensor built-in.
When brushing with an electric toothbrush, you don’t need to move the brush head around lots. It is different to a manual brush. Instead you move more slowly from tooth to tooth, letting the brush head (which is moving) do a lot of the work.
If it detects you are moving the brush head around too much, the scrubbing sensor will be activated.
Like the pressure sensor it vibrates the handle and illuminates the light ring. This time an amber colored light is emitted. It does not flash like the pressure sensor, it is a solid light.
When the scrubbing sensor is activated, the intensity and sound of the brush changes. But the intensity setting remains set to the one you have selected.
Stop scrubbing and the light will go out and the motor will return to full power.
Like the adaptive intensity, the scrubbing sensor can be turned on and off within the app. It is turned off by default.
The scrubbing and pressure sensor is all part of SenseIQ.
We have a separate article that explains SenseIQ in more detail. But essentially it is a term used to describe a number of different bits of technology built into the 9900. It is designed to sense, adapt and care.
It senses by monitoring your brushing frequency, duration, coverage, motion and pressure.
It adapts by adjusting the intensity (power) of the bristle movements.
It cares by helping you improve your brushing over time.
It analyses data from the various sensors at 100 times per second. This allows it to give the real-time feedback through the light ring and handle vibrations.
With these things covered, let’s take a look at the brush head.
The A3 Premium All-in-One head is made available at the same time as the Prestige. It is the first model to ship with it included in the box.
You get just 1 head included.
As the name implies it is an all in one solution. It is designed to do away with the need for different styles of brush heads.
For many years people have been confused about which brush head to use.
Our Sonicare brush heads article explains the differences between heads. You only need to read some of the comments on that article to see how confused users are.
We highlight when you might want to use each. Yet, our overarching message has always been to pick one and stick with it.
A brush head does play an important part. But, improving your oral care routine will provide greater benefits than any 1 style of head.
The A3 head feels like Sonicare are listening and taking a positive step forward here.
They are making it simpler for users. Yet another example of the simplicity theme.
It has been designed to do all of the things users request of a brush head. It removes plaque effectively, promotes healthier gums and whiten teeth.
Although the main body is of plastic construction, the back and sides of the head are made from a soft rubber. This makes it nice and gentle on the soft cheek and gum tissues.
The head simply pushes onto and pulls off of the brush handle.
There are longer bristles at the top and bottom of the head. The sides of the head also have slightly longer bristles compared to the very center.
This allows the brush to cup the teeth but also to allow the longer side bristles to gently brush the gumline.
The soft nylon bristles flex to absorb excess pressure and avoid unwanted damage.
I noticed myself how the bristles on this head appear to be quite a bit softer than many other Sonicare heads.
You can see the complex configuration of bristle clusters. These have been precisely engineered to clean the teeth well. Different locations and at angles to the clusters provide an effective clean.
Each bristle has a triangular tip. This is designed to help remove stains effectively from the outset surface of the tooth. The triangular shape offers more contact with the tooth surface than rounded bristle tips do.
Sonicare have published what seem like very impressive stats.
Their independent tests have shown that this A3 head removed 20x more plaque than a manual brush. It can achieve 100% stain reduction versus a manual toothbrush (in a lab test) for whiter teeth. And over a 6 week period it can achieve 15x healthier gums vs a manual toothbrush.
It all sounds impressive, but everyone’s mouth and teeth are different. There are hundreds of different manual toothbrushes as people’s brushing time and styles vary. So, the reality is you won’t get exactly the same results.
Perhaps more meaningful is the comparison to existing Sonicare brush heads. The C3 and G3 brush heads removed 10x more plaque, whereas the A3 head achieves 20x more plaque removal. This is quite a significant improvement.
Simply put, it cleans the teeth well. I can vouch for this. I have been using it for a few weeks and I have been impressed. It is soft and the clean feels thorough.
In fact, it feels like it gives the most intense and thorough clean I have ever had from a Sonicare toothbrush. This was noticeable from the first use. To some extent this reiterates that the layout and configuration of the bristles work.
Pair this with the sonic cleaning action and it makes for a great combination. It will serve the vast majority very well.
The clean is very good. I have no complaints.
I have no hard evidence to support this, but weirdly, I do think my teeth look whiter after brushing with Sonicare. They have a slightly whiter hue. It seems it could be better at removing the surface stains on the teeth.
It feels softer, and less intense than Oral-B.
I quite like the harsher brushing of Oral-B.
I come away with a stronger ‘just cleaned’ feeling than I do with Sonicare. But, this is just my opinion and you may feel differently.
The debate of Oral-B vs Sonicare will continue for a long time. There is evidence that argues both sides. The important thing to do is stick with a brush and use it correctly.
This A3 Premium All-in-One head, like most Sonicare now offers, is BrushSync enabled. This means it has the RFID chip built-in. Unfortunately, this can make it more difficult (nearly impossible) to recycle the brush heads.
For a company keen on being more sustainable there is some work to be done here.
For those wondering, it is fine to use the Prestige and the A3 head on bridges, crowns, implants and braces.
It is now time to dig into the smartphone application. I want to explain what it is, how it works and how you can get the most from it.
If you are not already familiar with smart toothbrushes, our guide goes into quite some depth about how they work.
The important thing to be aware of is that there are different levels of smart brushes. There are those that are Bluetooth enabled but in reality, offer little more than an on-screen timer. Then you have those that are fully featured and include real-time tracking of the brush. The Prestige 9900 falls into this later category.
At the time of review, the DiamondClean Smart has been the flagship smart toothbrush from Philips. It has been on the market for a little over 3 years. In many respects the Prestige 9900 looks and feels like its successor. Yet, Philips says it is not.
The DiamondClean Smart will be available for some time yet. It is still an excellent toothbrush. In fact, there are ways in which the Smart is better than the Prestige. View our Prestige 9900 vs DiamondClean Smart comparison for more information on this
The Prestige has more technology than the DiamondClean. But the key differentiator here is simplicity. I believe this is the reason you would likely want to opt for the 9900. The refined approach of the Prestige feels better.
I will be very clear when I say you do not need a smart toothbrush. They are very clever and can offer benefits, but they are not essential.
For many, similar results can be achieved by perfecting a good tooth brushing routine.
But, if you demand the best and you can commit, then a smart toothbrush like this can help you become a better brusher. It can help you take better care of your oral health, by forming better habits.
For those that own a smart toothbrush already. Unless yours is broken, I see limited reason to upgrade to this new Prestige model.
To take advantage of the smart features you need to connect the Prestige brush handle to your smartphone. To do this you need to use the free Sonicare app, available for Android and iOS. You will need a device running Android version 8 or iOS 13.0 for the app to work.
Once installed, the app can be opened and it will guide you through the pairing process. It should be relatively straightforward.
Do be aware you can only connect to 1 brush handle at any one time. The Sonicare app and Prestige brush handle is designed for 1 user. Technically you can share the brush handle. but, there is no way to separate brushing data for individual users.
If you want a smart toothbrush that works for all the members in your family, this is not it.
Connecting your handle offers a number of different features and functions. The key and most impressive of these is the real-time tracking. Sensors in the brush handle relay in real-time information to the app.
To get the maximum benefit, when you brush your teeth, have the app on your smartphone open at the same time.
You will have to open the app, it won’t automatically start when you pick up the toothbrush.
Once opened, you need to pick up your toothbrush. The lifting of your toothbrush activates the handle, but doesn’t turn it on. The app should then detect and connect to the brush within about 5 seconds (usually less).
You then follow the guided brushing routine on screen.
It breaks the mouth down into 6 sections and over the 2 minute brushing session it moves you through all 6.
It highlights the section you start with. As you get to 20 seconds it will highlight the section to move onto and so on.
On-screen there is a slightly dulled graphic of all your teeth. As you brush the teeth in the section turn white. This then allows you to clearly see what you have and have not brushed.
As you proceed around the mouth more teeth turn white. The aim at least is to have turned them all to white by the end of the brushing session.
The handle is smart enough to detect whether you are brushing the front or back surfaces. When it does it will adapt the graphic on screen to show the location you are brushing.
It does not yet detect or show when you are brushing the biting surfaces. These need to be brushed too, so it would be nice to see the app show this in the future.
When using this guided brushing routine, it will not detect if you are brushing the left side of the mouth when you should be brushing the right. You need to follow the app for it to register the data correctly.
Essentially if you don’t follow the guidance your data will be off. You could have spent 30 seconds or more brushing an area out of sequence. This will never register, even though you have brushed all teeth.
This is different to Oral-B and their smart brushes like the iO. These allow you to move around the mouth in a less consistent fashion and still track it. Neither is necessarily better or worse. But, sticking to a pattern/route will help ensure consistency and build better habits. And building good oral care habits is Sonicare’s aim.
I would like to see the app do more to alert you if you are brushing in the wrong area, with the intention of encouraging you to move back to the guided session. Perhaps it could with a future update.
I would also like to see more text on screen. The graphics work. But I think some would benefit from the app stating which surface to brush now, using text. For example, the app could suggest brushing outer tooth surfaces. It could then follow this up with biting surfaces and then inside surfaces.
The accuracy of the tracking isn’t 100% perfect all of the time. But, it is pretty good from what I have experienced. There can be a slight lag but it doesn’t cause any real problems.
Oral-B iO users complain that achieving 100% coverage within 2 minutes is difficult. You often have to brush for nearly 3 minutes to achieve this.
Sonicare doesn’t show the coverage as a percentage. But by white teeth in the app, it is possible to turn them white in 2 minutes.
Activate the pressure or scrubbing sensor when brushing and you will be notified on-screen. You will get the alert via the handle itself as well.
You will also see a timer so that you know how long you have been brushing for and how much time remains.
At the end of the session, your data is summarised on screen and logged within the app.
You are presented with 3 mouth maps. They are:
- Yellow teeth are the ones you have not brushed
- White teeth are the ones you have brushed
- Purple teeth are the ones you have brushed with too much pressure
- White teeth are the ones you have brushed without applying too much pressure
- Gold teeth are the ones you have scrubbed
- White teeth are the ones you have not scrubbed
Beneath each mouth map is a little bit of personalized feedback from the app.
The principle of guided brushing is showing you areas that you have not brushed correctly. It is to educate rather than tell you off. If you keep missing areas of the mouth, in the long term this could cause problems. The app is designed to highlight this to you, so you can take corrective action before it is too late.
This data is stored in your progress report by day, month and year. It is available for review at a later time if you want to look back and review your progress.
Each session is logged by date, and then by time. The coverage, pressure and scrubbing maps are stored for each session.
The dashboard is the best place to go. It gives an overview for the week or month. It calculates and shows the averages. Daily data can be useful, but average brushing data is much more powerful.
The dashboard gives you clear actionable insights, using bold colors, charts and visuals.
With the DiamondClean Smart, the mouth map data was only obtained if you had the app opened when you brushed. With the Prestige there is no need to worry about always having your phone with you. Thanks to the offline coverage tracking, this 3D mouth map data is available even if you didn’t use the app at the time of brushing.
The handle retains data and syncs with the handle when it is within range. If your smartphone is in another room, the brush can still send the data back to it. It does this all seamlessly in the background.
This is another part of the simplification process. You still get lots of valuable data, without using the app in real-time.
The benefit of using the app in real-time is that you can clearly see those areas you have missed. This means you can respond quicker and perfect your brushing.
As you use the Prestige, sensors in the handle are obtaining and storing lots of useful data. This is a positive and a negative. Lots of data means more information for review, but it can be too much.
But, to make things better for us all Sonicare uses Artificial Intelligence (AI). This intelligently sorts and understands this data. The AI presents personalized insights and feedback to help you brush better. This is all presented via the home screen and dashboard.
The theory is you can take action based on this feedback to improve your brushing.
It won’t be for everyone, but I can get behind the principle of what Sonicare are doing here.
The clear visuals and bold use of color makes it easy to see some of the highs and lows in your brushing routine. Green is good and orange are areas for improvement.
Sonicare suggests personalized feedback and to be fair there is some. It will use your name that you have typed into the app. But it might not be as comprehensive as you would expect. It is pretty standard stuff based on the data that is being fed into the app.
I am not knocking it, just aligning expectations.
For example, the data could show that on Tuesday and Thursday evenings you only brush for 1 minute. 30 seconds of which are with too much pressure. However, from what I can tell, it isn’t clever enough to highlight this specifically. And more importantly question why, if every other brushing session is perfect.
That said there is more than enough data shared and presented. You get a pretty good idea if you are doing well or not.
It doesn’t mean everything is perfect. But lots of green will likely mean you have better overall oral health than those with lots of orange icons etc.
As I have highlighted, you don’t need to have your phone with you when you brush. But, doing so gives you the best chance of taking corrective action.
The dilemma is where to put your phone. Do you hold it in your hand? Do you rest it on a shelf or worktop in the bathroom?
It would be nice if Sonicare included some form of phone stand/holder in the box. This would allow for your device to be securely held, out of harm’s way when brushing. I found I just tended to hold it at arms length from me when I brushed. Or I propped it up somewhere, hoping it didn’t slip and take a fall onto the tiled floor or into the sink.
Oral-B have the same issue. With some brushes they provide a holder, others they do not. It seems like companies don’t know what the right thing to do is. Admittedly many won’t want a smartphone holder in the bathroom. But if you are going to encourage app use, might it make sense to include something like this?
Aside from the real-time tracking the Sonicare app does offer a few extra features within the app.
Exactly what is available and how it looks may change with future app updates.
You get the ability to control the intensity and the cleaning modes available.
You can turn on and off the scrubbing sensor and adaptive intensity.
When you change a setting/mode brush vibrates and makes a sound confirming it has been updated. This is a very small but significantly important feature. Such subtleties make a big difference to your overall user experience.
A great feature is the ability to see the remaining battery power as a precise percentage.
This is the first Sonicare toothbrush to show battery power as a percentage (within the app). Before it has always been a more vague text status.
What is also worth noting is these key functions and controls are easily accessible. They are not buried deep within the app.
You can track each brush head you have fitted to the handle of the Prestige and learn how many uses you have left of each. You can also update the handle software, yes, this is a thing. And you can access generalized tutorials on how to take care of your teeth.
The home screen of the app does give a nice simplified overview too. It greets you. It then shows whether the brush handle is currently connected and the date of the last sync.
It will tell you the status of your brush head if there are limited brushing sessions left. It will also give you extra tips depending on your habits. If you are scrubbing or using too much pressure regularly it will give some polite prompts. These are to help and encourage you to reduce this.
What you see will depend on your individual circumstances. When you first connect the Prestige you will likely see tutorials/how to based content. This demonstrates how to use features and brush correctly.
At the bottom of the app are 3 key buttons/menus, these are home, dashboard and brush. There are then 3 dots. This is the extended menu.
Within this menu are the following items:
- Login to keep things up to date
- My products
- Key info about brush you have connected including the ability to update it
- My brush head
- Key info about the brush head(s) connected the brush handle
- Guideid brushing settings
- Change start location
- Add up to 3 focus areas
- Plaque buildup
- Bleeding area
- Gum recession
- You can add 3 in total, not 3 of each. It won’t necessarily add time
- Shop for products
- Lists the available Sonicare products with links to sellers
- Dental professional
- Add in an appointment for your next dental visit
- Data about the app itself
- Help and support
- Product information
- Contact us
- Controls over privacy settings of the application
As you can tell there is quite a lot to the app in terms of what is on offer and the data you can access.
I think it would be nice if you could change the total brushing time for each mode or at least customize it. For example, if your dentist wanted you to brush for 3 minutes.
It would be useful to be able to change to a 30 second/4 quadrant timer rather than the 20 second six section pacing.
These and a couple of other small changes could make the app more appealing for some. But, for the vast majority there is way more than you need.
Included in the box with the Prestige is a travel case. This might not be something everyone wants. But, it is very useful, particularly if you travel frequently. It protects the handle and head from damage and accidental activation.
The case provided with the 9900 is a Premium case. It is very fitting of this product type. It is not a cheap and basic plastic case like you get with a lot of brushes. It is strong, yet compact. It holds the brush handle and 1 brush head.
It is wrapped in vegan leather and that leather is color matched to the brush handle itself.
At either end of the case are plastic plates that are gold in color and match with the brush handle. There is also a small vegan leather strap to help hold the case securely. This strap is not removable, nor is it large enough to allow you to wrap it around the wrist.
If you look at the case with the strap at the bottom, the case hinges open on the left side like a book. Magnets keep the case securely closed and there is a satisfying thud when it closes.
The brush head gets positioned under the brush handle. This makes the case taller than it is wider.
Unlike most toothbrush cases you can actually charge the 9900 whilst it is in the case.
This is the first travel case to offer USB-C charging as far as I am aware. The connector is at the opposite end of the case to the strap.
To charge the toothbrush whilst in the case, you connect the provided USB-A to USB-C cable.
The USB-C connector goes into the case and the USB-A end goes into a USB socket on a power source such as a computer. Or you can use the included USB power adapter to connect to the wall.
The downside for me here is that the cable is detachable and there is no place within the case to store the cable.
Being able to charge the toothbrush in the case is better than nothing, for sure. However, it could be easy to mislay the cable or forget it. What is great about the DiamondClean Smart is that the USB cable is built into the case, so you always have it.
That said, offering a USB-C connection on the Pretige’s case is very current. More and more products use this connector. This makes the Prestige future proof. It also makes it fairly easy to obtain such a cable if you need it.
It is a shame that it holds just 1 brush head. Many travel cases hold 2. Then again, most people have their own toothbrush rather than sharing. It also keeps the case nice and compact.
And finally, it is important to know that the 9900 comes with a 2 year warranty as standard. This covers any manufacturing or workmanship defects that may occur during ownership. All being well it will stand the test of time. But, by the very nature, it is impossible to say it will be entirely fault free.
Summary of design, usability, clean & general use
- Revised design with a seamless power button.
- Buttons are pressure sensitive rather than resistive.
- Handle available in different colors.
- 3 different intensity settings.
- 5 different cleaning modes available.
- Visible pressure sensor built-in to alert you when brushing too hard.
- A scrubbing sensor can alert you when moving the brush too much.
- SenseIQ technology helps protect your teeth and build good habits.
- 1 x A3 Premium All-in-One brush head included
- Cleans the teeth really well.
- Brush head replacement reminder system.
- Bluetooth connectivity with real-time tracking.
- Offline tracking allows useful data to be stored without needing to use in real-time.
- Artificial Intelligence helps build better oral care habits through personalized feedback.
- Sense of simplification to the toothbrush despite being very capable.
- A smartphone holder would have been useful.
- The travel case holds 1 brush head and handle.
- The brush can be charged in the travel case via a USB-C connector.
- Water resistant handle.
- 2 year warranty provided.
We all have different expectations around battery life. Some are happy with just a weeks use on a full charge whilst others want their toothbrush to last a couple of months.
My satisfactory benchmark is around about 2 weeks. I say 2 weeks because this sort of battery life doesn’t make it feel like your brush is always on charge. It also allows you to go away on vacation and not have to worry about taking the charging stand with you.
Although the Prestige is a bit different with its charging travel case, but more on that in a moment.
Built into the handle of the 9900 is a rechargeable Lithium-Ion battery. This is pretty much standard feature across the Sonicare range. It is not user removable.
Sonicare claims a battery life of 2 weeks. This is based on 1 person brushing their teeth twice a day, for 2 minutes on the standard cleaning mode.
More often than not actual battery performance is quite different. Different, for the better. Take the Sonicare 4100 ProtectiveClean for example. The suggested life is 2 weeks, but it achieved 5 in my hands-on testing.
The Prestige is no different, which is great.
On a full charge I achieved 60 brushing sessions, using the ‘clean’ mode, with the intensity set to high. This is equal to 30 days.
That is a total of 120 minutes usage time, based on 2 cleans per day of 2 minutes in length.
I think it is pretty safe to say that 2 weeks is the least you can expect from this brush.
Given that the flagship Oral-B iO only achieved just 2 weeks at best, Sonicare is some way ahead.
Provided in the box is a charging stand. It is made up of 2 parts.
The first is the main charging base/plate.
This fairly thin circular pad is fairly lightweight due to the plastic construction. The base has 3 rubber feet to prevent sliding on a worktop. The sides and top are completely smooth to the touch.
The plate is gold irrespective of the variant. It is the same gold color as you find on the travel case and the brush handle. It is a small continuity of design.
Hardwired into it is a USB cable with a Type A male connector at the end.
The cable is approximately 100cm (39 inches) long.
This can connect to a USB connector on a power socket, computer, laptop or battery bank. Or you can connect it to the USB power adapter provided in the box and connect it into the wall socket.
The power adapter supports 100-240v. This means is that you can travel to other countries, like the UK for example and use this charging stand. You will need a plug adapter only and not a voltage adapter.
Or because it has a USB cable, you may not need the power adapter at all.
The Prestige could sit on top of this plate. But to help center the brush and give an extra bit of security, there is a frosted plastic part, known as the puck. This sits on top of the plate. Once fitted the handle sits within the center of the puck.
There is no prong on the charging stand and no recess on the base of the brush handle. It uses the same wireless charging as other electric toothbrushes. It is just implemented differently here.
When the brush is placed onto the charging stand the handle will beep twice and vibrate. This confirms it is charging. This won’t happen if the charging stand is not connected to a power source.
When the brush is on charge, you will get feedback from the battery charge/status light on the brush handle.
A flashing light indicated that the toothbrush is charging. When the handle is fully charged, the battery light goes a solid white for 30 seconds and then switches off.
A full charge can take up to 16 hours, if the battery is flat or very low. It is not a rapid charging time of 3 hours like you get with the iO from Oral-B.
The brush has technology to prevent overcharging. So it is ok to leave the brush sat on the charging stand when not in use. Whilst you can constantly top up the battery, for the best battery life, unplug the charger. Try to give the brush fuller charges rather than lots of short ones.
When off the charging stand the battery icon on the handle will provide some feedback on the remaining power.
- A solid white LED means a full battery.
- A flashing white LED means a medium battery.
- A flashing white LED and three beeps mean a low battery.
- A flashing white LED and five beeps mean no brushing sessions left, you need to charge the toothbrush.
You can get a more accurate battery charge status from within the app. This shows the remaining power as a percentage (%). This is the first Sonicare brush to offer this feature.
The Prestige is one of a select number of toothbrushes that can be charged within its travel case.
On one end of the travel case is a USB Type-C power connector. This is a great addition. It is fantastic to see Philips using a modern power connector.
Included in the box is a USB-A to USB-C cable (about 65cm in length), so you can charge it from a USB port. A USB power brick/adapter is provided as well, if you want to connect it to a wall socket.
Many new smartphones and other technology products use USB-C connectors. This means you could share the same charger with your phone and Prestige toothbrush. You don’t have to use the one provided.
The DiamondClean Smart from Sonicare has a USB cable hardwired into the case. This means you always have the cable with you. With the Prestige, this cable is detachable.
It is a bit frustrating that there is nowhere to store this cable within the case. You have to carry it separately. I acknowledge you won’t need it all the time. But, it is easy to misplace or forget.
I don’t think it would have made the case that much larger to store it inside. But, I do accept it may have altered the design a little. Clearly this is not a big issue. It is a much better solution than Oral-B’s which involves a bulky proprietary power adapter. It is just something to be aware of.
Sonicare doesn’t state how long it takes to charge in the case. I haven’t been able to determine this either in my testing. I do know that a charge of 8 hours will fully charge the battery.
You don’t get any charging lights on the outside of the case. You need to open it up to see the battery icon on the brush handle to see if the charge is complete or not. A complete charge will mean all the lights on the handle will have gone out.
When the power cable is connected to the case the brush handle will beep twice and vibrate to confirm it is charging.
Summary of battery life
- A claimed 2+ weeks of battery life.
- Achieved around 4 weeks in hands-on testing.
- A rechargeable lithium-ion battery built-in.
- Comes with USB charging stand.
- USB power adapter provided.
- The charging stands supports 100-240V.
- Can take up to 16 hours to charge fully.
- Battery icon on handle gives feedback on remaining power.
- Exact battery percentage (%) available within the app.
- The display shows battery charge in 10% increments.
- The travel case allows the toothbrush to be charged inside.
- USB Type-C connector on case.
- Detachable USB-A to USB-C cable provided
Price & where to buy
I have included links to buying options here at the start of the review.
In the section below, I discuss the price more generally and in relation to similar products.
As you will have realized by now, the Sonicare 9900 Prestige is a feature rich toothbrush. This means it isn’t going to be the most cost effective brush you can buy. You are going to have to pay a premium for the extra technology built-in.
The suggested retail price is $399.99.
The flagship DiamondClean Smart had a retail price of up to $360 when it launched several years ago. Therefore, a further $40 premium for the Prestige 9900 isn’t all that surprising.
Is it worth this? No.
Yes, it is comparably priced to the most other premium electric toothbrushes. But, there is limited justification to pay as much as this for a toothbrush.
You can get much more affordable options that clean the teeth just as well.
If you really want it and are prepared to pay for it, then I can’t stop you. It is a very impressive piece of kit.
But, going in our favor is the fact that more often than not there is some discount on this price. It does vary, but it is pretty common to achieve around 20% discount.
This means the more typical selling price is $320. It is still a lot of money, but it is a saving nonetheless.
Another factor to consider is the ongoing cost.
You need to replace brush heads on average every 3 months.
The exact price depends on the head you buy, the pack size and the seller. But, as a rough guide a BrushSync enabled head will work out at around $10 each.
A typical working life of an electric toothbrush is normally around 5 years. Many will, in fact, last a lot longer, with good care.
Here at Electric Teeth, we like to price the brush over a 3 year period. This will give a benchmark of ownership cost and allow comparison to other brushes.
There is the initial purchase price of approximately $320 for the brush. Add in the cost of replacement brush heads at approximately $10 each and there is an additional cost of $110 over 3 years.
The total cost, therefore, comes to $430 or $0.39 per day.
As you might expect, this isn’t cheap.
If you paid the full price for the Prestige you would be looking at $510 or $0.47 per day.
The very capable DiamondClean Smart works out at around $0.29 per day.
Oral-B’s iO comes in at $0.28.
Our best value Sonicare toothbrush, the 4100 Series costs just $0.14. A third of the price.
Or even better value is the Oral-B Smart 1500 at $0.11 per day.
It isn’t all about price. But, it is something that many of us will need to factor in.
If you think the Prestige is worth it be my guest and go ahead and get it. You are unlikely to be disappointed.
I am just trying to shine a bit or reality on the price.
As clever and useful as the tech is, it requires commitment. You could pick up brushes a third of the price. Then perfect your brushing technique, without having to invest extra money. You would need to learn how to brush your teeth properly and monitor areas for improvement.
Sharing the brush handle (switching heads) with other users will help bring the cost down. But, it would ruin the smart features of the brush as they are not designed for use by different users. It is all centered around 1 user.
Please note that all prices quoted are approximates and will vary based on location, supplier and time of purchase. These figures were correct at the time of writing and should not be relied upon as hard fact, but used as a guide during your decision process.
Summary of price & where to buy
- List of buying options included here
- A recommended retail price of $399.99 for 9900 Prestige.
- The typical selling price is usually 20% less than retail.
- The typical selling price around $320.
- Replacement brush heads cost approximately $10 each.
- Ownership over 3 years to be in the range of $0.39 per day.
Reliability & long term use
In the few weeks that I have been using this brush I have not experienced any reliability issues. Nor have I noticed any elements of the brush that should be a real cause for concern.
In the years I have been testing Sonicare brushes, I have only had 2 brushes fail on me. Both were outside their 2 year warranty period.
Feedback would suggest this is not always the experience others have had. Select models, notably the DiamondClean (not the smart version) has been more prone to reliability issues.
I do believe Philips will have learnt from this. One of the things that have really highlighted as part of the Prestige is the seamless button design. There is no physical gap around the power button. This stops gunk building up around the button and causing usability problems. To me this is an admission that this is a problem that has been experienced in the past. They are looking to overcome this with this new approach.
Philips has fairly high standards of production. As an established brand, reliability should be better than lesser known alternatives. By the very nature of the product, they can’t ever be 100% fault free. But, should the worst happen there is a 2 year warranty that you can make use of.
You could also take advantage of the Sonicare 90 day money back guarantee if you are not happy with it for any reason.
I am happy to admit that I like this toothbrush a lot.
It performs well. The clean of the teeth is great and it looks good.
There are lots of premium elements. For example, the travel case is practical and classy. You wouldn’t know it was a toothbrush inside.
The smart technology works. I like the fact that more data syncs in the background and you don’t need to have your phone with you every time you use it.
The simplification works. I think many new users will be as impressed as I am.
It feels a more complete and refined option in comparison to the Oral-B iO.
I do believe it is the best smart toothbrush on the market today.
But, and yes there is a but.
This is a top of the line toothbrush. You are paying at least twice that of the best value options.
There is value in the extras, but is it worth twice as much? Ultimately, no.
You are going to need to commit to making the most from the app to get the benefits. If you can commit to this, I believe you could commit to learning the essential steps you need to improve your general oral care routine. This would include technique, brushing time and frequency. This learning wouldn’t take much time and adds no extra cost.
The sensible choice is to buy a more cost effective brush and enjoy the monetary savings.
But, if you desire to own the best, then the Prestige is it.
- Height (without head) – 17.5cm / 6.9 inches
- Height (with head) – 24cm / 9.4 inches
- Width – 2.7cm / 1.1 inches
- Thickness – 2.8cm / 1.1 inches
- Weight (without head) – 117g/4.1oz
- Weight (with head) – 123g/4.3oz
All are approximates
- Is the Prestige 9900 an oscillating brush?
- No, it is a sonic toothbrush, with a sweeping action brush head.
- What brushing/cleaning modes are available?
- The Prestige 9900 has 5 cleaning modes, although only Clean mode is available by default.
- The additional modes must be activated via the app.
- All of the modes available are:
- Clean Mode
- White/White+ Mode
- Deep Clean/Deep Clean+ Mode
- Gum Health/Gum Care Mode
- Sensitive Mode
- Learn more about Sonicare electric toothbrush cleaning modes.
- What brush head does 9900 Presitge come with and what alternative ones can be used?
- 1 x A3 Premium All-in-One brush head is supplied.
- Sonicare offer a total of 12 different brush heads, each of which can be purchased separately and used with this toothbrush. Those options are:
- C1 Pro Results
- C2 Optimal Plaque Control
- C3 Premium Plaque Control
- G2 Optimal Gum Care
- G3 Premium Gum Care
- I InterCare
- S Sensitive
- W DiamondClean
- W3 Premium White
- T1 TongueCare+
- A3 Premium All-in-One
- Does the Philips 9900 have a pressure sensor?
- Yes, it does.
- Does the Prestige have Bluetooth?
- Yes, it does.
- Does it come with a travel case?
- Yes, a travel case is included.
- It holds the handle and 1 brush head.
- The toothbrush can be charged in the case using the provided USB Type A to USB Type C cable.
- Does it come with a charger?
- Yes, a charging station is included with the 9900.
- It can also be charged in the travel case.
- How long does the battery last?
- The battery lasts up to 120 minutes, which if used on the standard daily clean mode is 30 days based on 2 cleans per day.
- Can I use the Prestige in the shower?
- It is not advised. Although the handle is water resistant, the manual supplied does not specifically state that you can or you cannot. Do not submerge it in water.
- Does the Philips 9900 come with a warranty & how long is it?
- If purchased new from an approved retailer the brush will come with a 2 year.
- How do I turn the Adaptive Intensity feature on and off?
- This is turned on by default.
- You can turn the feature off or on within the Sonicare app.
- Open the Sonicare app.
- On the pre-brushing screen, tap the ^ button to expand the toothbrush settings.
- In the Adaptive Intensity section, tap on the blue toggle slider to switch the feature on or off. The feature is on if the white circle is over to the right.
- How do I turn the Scrubbing Feedback feature on and off?
- This is turned on by default.
- You can turn the feature off or on within the Sonicare app.
- Open the Sonicare app.
- On the pre-brushing screen, tap the ^ button to expand the toothbrush settings.
- In the Scrubbing Feedback section, tap on the blue toggle slider to switch the feature on or off. The feature is on if the white circle is over to the right.
- How do I change the cleaning mode?
- The clean brushing mode is enabled by default.
- You can change the cleaning modes from within the Sonicare app only.
- Open the Sonicare app.
- On the pre-brushing screen, tap the ^ button to expand the toothbrush settings.
- Tap the mode box. You will see your current selected mode, and the options to choose between.
- Tap on the circle next to the mode you want to change to.
- When you see a check mark on the update screen, your mode has been successfully changed.
- Tap the < arrow to start brushing with your new mode.
Do you own or have you used the 9900 Prestige from Sonicare?
Are there certain features that you really like or dislike?
Let us know what you think about this brush and let others who may well be considering purchasing one know your opinions before they do.
The 9900 Prestige brush spoken about in this review was provided by Philips PR department. Electric Teeth did not purchase this model. No financial reward was provided to conclude the review the way that we did. No editorial control was given.