In 1945 Joseph C. Muhler was a first year dental student in Dr. Harry G. Day's biological chemistry class. Dr. Day selected a few students, including Joseph Muhler, to conduct laboratory tests on fluoride in bone and teeth. This publication represents one of the earliest published studies on fluoride from Indiana University.
Muhler, J. C. (1946). Toxicity of fluorides in dental health. Dental Student, 25(2), 28-30.
Journal of the American Dental Association, 1955
Researchers had long suspected that fluoride could impact tooth enamel and that regular, low-level exposure to fluoride would be beneficial rather than special, topical applications. It made logical sense to incorporate fluoride as a dentifrice additive which was already used daily. In 1955, Muhler et al. reported significant reductions in cavities as well as reversals in caries diagnosis in children using fluoridated toothpaste.
Muhler, J. C., Radike, A. W., Nebergall, W. H., & Day, H. G. (1955). Effect of a stannous fluoride-containing dentifrice on caries reduction in children. II. Caries experience after one year. Journal of the American Dental Association, 50(2), 163-166.