I have used Crest 3D White Whitestrips Professional Effects and had great results. The best time to whiten your teeth is after a cleaning/polishing at your Dentist. Debris, plaque, etc has been removed.
i bought Crest 3D White Intensive Professional Effects Whitestrips and let me tell u girl they work really good my teeth got super white! and i only used them 3 times.most ppl say that they make ur teeth hurt by mine didnt hurt at all.
I agree, they work really well. I noticed that when I use them more than 2 days in a roll, my teeth start to become extra sensitive and hurt. I usually space them out (2-3x/week). You will still notice whiter teeth but without the teeth sensitivity. I don't use the entire box. Usually just do 2-3 strips the week before an event.