Question: how often do you have to use whitening strips?
Answer: Yes, Crest 3D Whitestrips do not harm tooth enamel and are safe to use, so you can use one pack right after another. With that said, Crest 3D Whitestrips will whiten teeth for at least six to 12 months, so we recommend using Whitestrips twice per year to maintain a whiter smile.