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Philips Sonicare DiamondClean Smart 9500 Review

This top-notch toothbrush is packed with smart features but comes at a hefty price
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Price:   $270 List | $240 at Amazon
Pros:  Great cleaning power, stylish, solidly comfortable
Cons:  Exorbitantly expensive
Manufacturer:   Philips
By David Wise and Austin Palmer  ⋅  Oct 10, 2018
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#2 of 11
  • Comfort - 40% 6
  • Cleaning - 30% 8
  • Ease of Use - 20% 6
  • Battery Life - 10% 6

The Skinny

Finishing in the upper portion of the group, the Sonicare DiamondClean Smart is undeniably a great toothbrush. It did very well in our cleaning tests and is both comfortable to brush with and convenient to use, with a solid battery life to boot. It's got a sleek and stylish appearance and includes a comprehensive set of smart features. Unfortunately, all of this performance comes at a price and the DiamondClean Smart is prohibitively expensive for most people.

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Our Analysis and Test Results

The DiamondClean Smart slightly outperformed the Sonicare Series 2 and finished just behind the Brio SmartClean in our testing process. While the Brio is the most comfortable of this trio, the Sonicare DiamondClean Smart did do the best in our cleaning test. It is a little less convenient to use when compared to the Series 2 and can't match the Brio when it comes to battery life. Additionally, the DiamondClean Smart is by far the most expensive of these three brushes, costing about $200 more than either of them.

Performance Comparison

We have spent the past two years buying, testing, and comparing the performance of the best electric toothbrushes on the market in our quest to find the best. We divided up our testing procedure into four weighted rating metrics, with the DiamondClean Smart's results when it came to cleaning, ease of use, comfort, and battery life explained below.


Comprising 40% of the total score, our set of comfort tests has the most bearing on the final score for each toothbrush. We had a panel of testers rate the brushing comfort of each product, as well as comparing the noise level and the ability to detect too much brushing pressure to finalize the scores. The DiamondClean Smart delivered a decent showing, meriting a 6 out of 10 for its results.

None of our panel of judges had any major issues with this toothbrush, with most of them rating it as one of the more comfortable models. We particularly liked how this toothbrush felt to hold, with its matte finish and size feeling very ergonomic in your hand. However, some of our testers with more petite mouths did find it slightly unpleasant when brushing their back molars and this brush is just powerful enough to be a little too much for those with the most sensitive gums. However, you can use the sensitive mode to mitigate this if you find that it bothers you.

This toothbrush is about average in terms of noise, being overall one of the quieter brushes in terms of amplitude. However, we did find this brush to have a high pitch whine that can be a bit irritating.

This toothbrush also won some extra points by having a pressure sensor that will slow the brush down if you are pressing too hard.


For our next metric, we ranked and scored how well each brush cleaned by performing a plaque removal test. This accounts for 30% of the final score for each toothbrush, with the DiamondClean Smart tying for the top spot of the entire group and earning an 8 out of 10.

For this test, we had our judges skip brushing their teeth in the morning and encouraged them to consume as many sugary foods as possible. They then used a plaque disclosing tablet in the afternoon, which stained all of the accumulated plaque over the 16 hour period or so since they last brushed a bright red. We then took before photos, had them use the DiamondClean Smart for a standard cleaning cycle, and took after-brushing photos, using those to determine scores.

The DiamondClean Smart removed virtually all of the stained plaque for most of our testers, with only one person missing a few of the harder to reach places on the inside surfaces of their teeth, putting it on par with the best brushes that we have seen to date.

Ease of Use

Accounting for 20% of the final score, our Ease of Use metric came next. We graded and judged how easy to use the interface to run and switch cleaning modes on each brush is, how difficult it is to clean, if there is an easy option for storing additional brush heads, and if there is a two-minute timer to ensure you brush the correct amount. The DiamondClean Smart again did quite well, receiving a 6 out of 10 for its performance.

It is quite easy and intuitive to switch between modes using the additional mode select button. You simply press the button to cycle through the different cleaning options, of which there are 5, and the mode indicator you are in will light up accordingly.

The charging cup does not have any storage for additional brush heads, but the USB charging case does have spots to store two brush heads.

This brush does have a 2-minute timer with intervals to help you pace out your brushing.

Battery Life

For the remaining 10% of the total score, we assessed the battery life of each electric toothbrush. To take both brushing and standby power draws into account, we ran each brush for a standard brushing cycle in the morning and evening, awarding points on how many days each one lasted. The DiamondClean Smart finished out with a solid showing, earning a 6 out of 10.

This toothbrush lasted for 24 days in our test — impressive, considering the standby power draw of the smart features.


This brush is the absolute worst option if you are shopping on a budget. Period.


While the DiamondClean Smart is a very cool, top-notch electric toothbrush that scored well across the board, its extraordinarily high price tag makes it quite hard to recommend.

David Wise and Austin Palmer