Flouridation In 1931 at the University of Arizona Agricultural Experiment Station M. C. Smith, E. M. Lantz, and H. V. Smith discovered that when given drinking water supplied with fluorine, rats would develop tooth defects. Further testing by H. T. Dean and E. Elove of the United States Public Health Service confirmed this report, and stated that what is known as mottled tooth. Mottled tooth is a condition in which white spots develop on the back teeth. Gradually the white spots get darker and darker until the tooth is eroded completely. This was believed to be caused by fluorine in drinking water (Behrman pg. 181). A s