What makes "Sensodyne" work?

My dentist told me to stop using my regular toothpaste (Aim) for a few weeks and just use Sensodyne when brushing my teeth. It’s supposed to Relieve “Painful Sensitivity” which I at first took to mean that it’s “less harsh” than regular toothpaste. But I read on the back…

“Do not use this product longer than 4 weeks unless recommended by a dentist or doctor.”

So now I’m thinking it changes the teeth somehow to make them less sensitive. But how? And what happens if you use it for 6 months, or a year?

The ingredients sound fairly alarming. And it tastes nasty. And it burns when I try to swish.

POTASSIUM NITRATE (5%)
SODIUM FLUORIDE (0.15% W/V FLUORIDE ION)

What’s the deal? Thanks in advance for any clues to what I’m putting in my mouth.

The current understanding of tooth sensitivity is that the tooth, which is supposed to be a nonporous mineral matrix, for whatever reason erodes and has tiny channels that can transmit sensation to the nerve. The sensitivity paste has minerals that help “remineralize” the tooth and block these channels after several weeks of use.

If you got this sensitivity by scrubbing your gums until the roots are partially exposed, the sensodyne isn’t going to help much though.

http://www.dentalgentlecare.com/sensitivity.htm

From DIY Dentistry.

I’m not sure why you’re getting a ‘burning sensation’. I’d recommend trying a different toothpaste - all the ‘sensitive’ toothpastes contain the same active ingredients in the same percentages. One of them might taste better for you. (And they’ll probably be cheaper, too).

I use it (all the time…my dentist said it’s ok). But he told me to switch to Crest for Sensitive Teeth, as it is reported by most users to be better than Sensodyne.