How can do you whiten bonded teeth?

I had my teeth bonded about 3 years ago and they stayed pretty white for the first few months now not so much. How can I whiten them? iv heard normal whitening kits wont work on bonded teeth is that true? Anyone who has had bonded teeth do you know of a product i could get to whiten my teeth?
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The bonding being basically a plastic material will pick up stain, and porcelain will not. Some times the stain can be superficial and can be polished off. But often it will be throughout the filling material and the only way to correct this is to replace the filling. And you are right that any whitening system will not lighten the composite fillings. Consult you dentist to see the best way to handle this. Good luck.
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