If fluoride is effective as dentists claim does this make sense?

In the 2004-2005 school year, the Winnebago County Health Department spot checked more than 11,000 students in Winnebago and Stephenson counties and found 35 percent needed routine treatment and nearly five percent needed urgent attention — meaning they had five or more cavities or had developed abscesses.

Extract - click title to see full report. Illinois is a fluoridation mandated state(NYSCOF)