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Comment by johnchristopher | Hacker News Reader

> my 10 year old Sonicare is starting to shit the bed so I started to look for a new one. Back then there was 2 models. Now there's like 8, each with several variations

Electric toothbrush marketing designations are out of control. When I was looking for one I found a website that went out of its way to identify which models were behind marketing wording and numbers and what their specs were (mainly: movements per minute and pulsations per minute). Companies love to rebrand the same models with different numbers based on how many additional brushes they put in the package but they rarely put those specs on their own websites. Anyway, oral b 2700 still looks good.

> is starting to shit the bed

Off-topic but... language, please ?

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> movements per minute and pulsations per minute

According to an ex-Sonicare senior engineer I work with, this is not actually what's important at all. The key thing they looked at (and still do look at) is the amplitude/travel distance of the bristle tips, and how that changes under load. It should stay strong under light load, but collapse under heavy load (so that when you mash the thing way too hard into your gums, power transfer stops and your gums don't get brutalized). It's a surprisingly delicate balance.

We recently had cause to look at a few of these devices (sorry for the vagueness, you know how it goes) and most of the non-Sonicare ones are pretty awful. The rotary Oral-B ones aren't bad at what they are, but they aren't the same. There is one Sonicare clone that really impressed though, and it's not expensive.

> The key thing they looked at (and still do look at) is the amplitude/travel distance of the bristle tips, and how that changes under load. It should stay strong under light load, but collapse under heavy load (so that when you mash the thing way too hard into your gums, power transfer stops and your gums don't get brutalized). It's a surprisingly delicate balance.

Isn't that what the pressure sensor is supposed to be for ?

I'm describing the what and why, not the how. The older? better? models don't use or need any pressure sensor, it's all designed in to the resonant motor mechanism. The "new" pressure sensor is 100% marketing.

> There is one Sonicare clone that really impressed though, and it's not expensive.

Come on. Don't do that without naming it.

> oral b 2700 still looks good

I thought the same until I tried a Sonicare. The cheap Oral B models feel more like power drills in comparison (and also started destroying my gums).

Which model ?

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