Is that normal? l mean it usually just last for a second but on certain teeth it really hurts!

Has that ever happened to you?

well katy, what is happening is that the crest white strips r making ur teeth extremely sensitive. l know what u r talking about, l myself using a crest white light, which uses a type of ultraviolet light & some gel stuff to whiten ur teeth. l had to stop using it because my teeth became so sensitive after a while, that l could hardly eat or drink anything. l would suggest to keep using them, but if it starts lasting more than the short period of time u said, then l would immediately end the use. hope that helps katy.

Another suggestion would be to try a fluoride rinse twice a day. This will help with the sensitivity you are experiencing. We call these ''zingers''. It is common during whitening and will usually go away after you quit whitening. You can also try a toothpaste like Sensodyne.

to make your teeth less sensitive to the whitening process you'd want to start using fluoride on regular bases. Usually dentist has prescription strength paste in the office for sale, ask yours.