The above 2012 chart shows that fluoridation has no effect on tooth decay in New York State. The counties on the bottom are listed according to rate of fluoridation. The dark blue line represents fluoridation. The pink line is the cavity rates of 3rd graders. The light blue (or teal) line shows that decay rates are actually going slightly upwards as fluoridation rates increase. This chart is based on NYS Department of Health statistics.
The below chart shows that fluoridation didn't close the gap between poor (red line) and non-poor (blue line) and that fluoridation is not correlated to less tooth decay. This is based on 2004 NYS Dep't of Health statistics. The trend line in decay rates goes slightly upwards as fluoridation increases (light green)