Which type of teeth whitening kits will give me the fastest results?

I need to buy a teeth whitening kit. Which product or brand will give me the fastest results (in one week or less)?
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Your best bet is to go to your dentist and get trays because then you know they'll fit your teeth. It can be quite expensive, over her it's £140 per tray..so £280 for uppers and lowers, but after you have the trays you have them for life. And you get a kit included in the price, but if you want them whiter all you have to do is buy more bleach which is about £15. If not, then I'd say crest whitestrips supreme are your best bet.
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