Hey Ladies, Just wanted to add some info to this thread, I am a Dental Hygienist, so this is what I do all day long, remember even in the same profession everyone has different opinions especially on elective procedures doesn't necessarily mean one is right or one is wrong so here is my OPINION
First thing First never ever buy those off the wall whitening products you may see on tv, like the $20 UV light or God forbid, those setups in the tanning salons or mall!
Crest White Strips are Great! Our practice highly recommends them, they are just as good as the Custom Tray Bleaching, they are just not as high of a concentration of the bleaching agent, however the custom trays are actually fitted to your mouth so you will get into the "hard to reach" in between parts of your teeth better than the strips. Zoom/ Zoom2 Whitening, this is basically just the I'm to lazy to wear trays or need it done tomorrow method, unless I was given a deal on it, I wouldn't pay the amount unless I needed it done ASAP.
As for sensitivity its completely normal, the best thing you can do is use a sensitivity toothpaste at least for a couple days before you start ( at least a week or two for Zoom), it takes sensitivty toothpaste two weeks to work and also you need to be using it for the full two minutes while brushing or it isn't going to work either, the bleach can make your gums sensitive will go away though...absolutely do not stop flossing! IMO best senitivity toothpaste are sensodyne or crest sensitivity, if one doesn't work for you the other should ( they work in 2 different ways)
Up Keep: No matter what the box says make sure you brush and floss before using....whitening doesn't "fade" its your daily habits that will affect the color of your teeth, commonsense stuff like smoking, coffee, tea, drk cola also remember red wines, blueberries, red sauce...just drink through a straw and you will be fine!