The U.S. Centers for Disease Control thinks that cavities are a big deal and that they were an even bigger deal in the past - before fluoride. Tooth decay is and was a major problem.
And like all good science papers do. CDC's paper on fluoride as a twentieth century triumph for public health started with a review of the problem. A review to get us all on the same page about that problem.
Photomicrograph of Streptococcus mutans, the #1 bacteria that causes cavities
Let's get clear what CDC says cavities really are and what their significance was over the course of the 20th century
With a series of fluoride tooth decay articles, let's review: