teeth whitening?

I had my teeth whitened at the dentist over a year ago. Unfortunatly I am a smoker and they're not as white as they were. Do the crest whitestrips really work? Which ones are the best...there are some different ones and I just wanted to know which is the best and how good they really work....Thanks
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//// whitening system you can purchase from drug store don't work , even if it works , it is only temporary, you need to do brite smile system with your dentist
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