How do toothpastes for sensitive teeth work?

I've read that they contain potassium nitrate... How does it interact with teeth?

How do toothpastes for sensitive teeth work?
the active ingredient blocks the open ends of the dentine tubules,restoring the 'seal' that was provided by the enamel that has probably worn down due to heavy brushing.
Reply:These toothpastes desensitize the tooth nerve directly. Treating teeth with fluoride mouthwashes also can help reduce tooth sensitivity.
Reply:Tooth paste for sensitive teeth does work but it may need time to work for you. It wont happen overnight.
Reply:There is a chemical called potassium nitrate that blocks the tiny tubes that lead to the nerve of the tooth. This is what decreases sensitivity.
Reply:The two answers above me are correct. Here's a photo that is MONSTROUSLY enlarged showing dentinal tubules. The potassium nitrate precipitates into the openings and eventually plugs these holes up.





http://oralhealth.dent.umich.edu/VODI/ht...





Here's another picture that explains why that works. If you ignore the enamel layer, which is not present on the roots, you will see that the dentinal tubules go all the way from the pulp chamber (where the nerve lives) to the outside world. There is fluid in the tubules. Some nerve fibers actually enter the tubules. Anything that moves or disturbs the fluid might be transmitted to the nerve fibers. This is usually interpreted as pain. Blocking up the tubules will reduce the possibility of this from happening.





http://www.adha.org/CE_courses/course9/f...



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