You don’t have to be too concerned about the safety of using expired crest white strips. Expiration dates are there because the product will lose its effectiveness over time. Crest 3d Whitestrips Dental Whitening Kit Glamorous White 28 Strips Although crest 3d white whitestrips that have passed expiration date are still safe, we don’t recommend using them past their expiration date, as the whitening ingredient’s efficacy will be. Do crest white strips work after expiration date . They are crest 3d white strips btw. I have a package of crest white strips premium plus my friend gave me from his work they have expired are they still effective after expiration date? The expiration date is october 2012. Some effect is better than throwing away. Nevertheless, there is very little reason to do so. For example crest 3d white 2 hour express claims that you can get whiter teeth in just two hours, and bills itself as the whitening kit you should use when you have an unexpected import...