Help! When I got my braces off there was a grey stain on my teeth - how do I get rid of it?

I think the metal left a stain on my teeth and I want it removed - will teeth whitening done by a dentist remove it?
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Is it smooth or rough? It may be some cement left on there. If it's rough it's cement and you need to go back to the Ortho to get it taken off. If it's smooth I have no clue...just ask your normal dentist.
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