Words not so much?
"Uncle Tom" is still used today as a derisive term. We've already discussed "pickaninny." Even Aunt Jemima has moved away from the "Mammy" image.
The words are still powerful.
Some of them have remained in use, but the power they're carrying now is the power that came from the book, they didn't give power to the book. But pickaninny is not on that list, the word has basically gone away, like ugly fashions it crops up again every 20 years or so but for the most part it's on the ash-heap of history like most of these http://en.wikipedia.org/wiki/List_of_ethnic_slurs .