Do those whitening and enamel building tootpastes actually work?

[Abitrary]

I've heard that some of those pastes can be abrasive. I asked my dentist about this and he said:

'Imagine a mountain made of diamond, in a strange land, and once a year a bird comes to sharpen his beak upon it. When the mountain is no more, then neither will we'

 

[tomb1960]

What's so bad about yellow teeth?!