How do they do teeth whitening at the dentist?

And does it hurt? How old do you have to be to get it? Thanks :)
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Teeth Whitening is basically a result of the abrasive nature of the whiteners. Bleaching results in the moisture content of the teeth being sucked out and thereby the result is a whiter appearance of the teeth. Do go through the articles in the source link from which I provided this answer.
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