Philips Sonicare 9900 Prestige Electric Toothbrush, 5 Brush Heads, Blue

Why it's worth it

The DiamondClean Prestige 9900 reads how hard you're brushing and quietly adjusts as you go. If your gums have receded or your teeth twinge at cold water, this is the brush that cleans seriously without making you flinch.

SenseIQ handles the pressure problem for you. Most sensors warn you and leave the rest up to you. This one senses what you're doing moment to moment and dials the intensity back on its own. If your teeth are sensitive, that's the difference between a brush you use twice a day and one you start skipping.

The cleaning numbers are the highest Philips claims. Up to 20 times more plaque removed than a manual brush, and up to 15 times healthier gums after six weeks. Healthy gums matter more for whitening than people expect — inflamed, receding tissue exposes darker root surface and makes every whitening product sting.

From our review of 11 electric toothbrushes for whitening, by Eleanor Vance, Health & Beauty Editor

What we like

• +SenseIQ handles the pressure problem for you
• +The cleaning numbers are the highest Philips claims
• +Five Premium All-in-One heads come in the box
• +The travel setup is genuinely good

What to know

• –It's the most expensive brush in this guide by a clear margin
• –SenseIQ can feel like it's nannying you
• –The charging stand stays home