Oral-B iO 3 vs Sonicare ProtectiveClean 5100

Oral-B's magnetic iO drive is the main reason to pick the iO 3 over the brand's older entry brushes. Models like the Pro 1000 oscillate the head with a gear-and-spring mechanism, and you can feel it: a buzzy, rattly sensation that gets tiring by the second minute. The iO line swapped that hardware for an electromagnetic drive that moves the head at 40,000 micro-vibrations per minute. It runs smoother and noticeably quieter, and the iO 3 is the cheapest brush Oral-B sells with it. That's a real hardware upgrade, not a rebadge of decade-old technology.

Sonicare cleans differently. The ProtectiveClean 5100 vibrates at 31,000 brush strokes per minute, and instead of scrubbing the tooth surface directly it agitates the saliva film around each tooth — the fluid motion does part of the work. Dentists often steer patients with gum recession or exposed root surfaces toward sonic brushes for exactly this reason, and if you've never owned an electric brush, the gentler action spares you the adjustment period that an oscillating head like the iO's demands. The 5100 also happens to be the cheapest Sonicare with a pressure sensor. If gum health is why you're shopping, treat that sensor as the minimum requirement, because everything below it in the Sonicare lineup leaves you guessing about force.

And the two pressure sensors aren't equal. Press too hard with the 5100 and it simply stops vibrating until you ease off, then restarts on its own. You can't ignore it. The iO 3 instead lights a small LED on the handle, and noticing a little light while steering a brush around your molars at 6 a.m. is a test plenty of people fail. Hard scrubbing is the main way electric brushes damage gums. This difference is worth more than most of the spec table, and for gum protection the auto-pause wins.

Neither brush has Bluetooth or an app. Good. App-connected brushes want a phone propped against the bathroom mirror every morning, and the evidence that coaching apps change brushing habits any better than a plain timer is mixed. Both models have the 2-minute timer with 30-second quadrant pulses, the one habit most dentists say actually matters.

Spending more in either lineup buys app coaching, specialty modes like whitening, and brighter displays. None of it changes how clean your teeth get. Buy the iO 3 if you want the smoother, quieter magnetic drive at the lowest price Oral-B offers it and you already brush with a light hand. The 5100 is the safer pick when anyone in your house scrubs too hard or has sensitive gums, since the auto-pause corrects that without asking you to notice anything. Either one beats a manual toothbrush by a margin that makes the rest of this page look like fine print.