The August 1, 1943, Journal of The American Dental Association referenced Dean as acknowledging the difficulty of identifying an optimal concentration with the following quote, "The same amount of fluorine that causes a mild toxic reaction in one individual may cause a severe reaction in another.
A quote from the August 1, 1943, Journal of The American Dental Association attributed to Dean highlighted the difficulty of determining an optimal fluoride level, as he noted, "The same amount of fluorine that causes a mild toxic reaction in one person may cause a severe reaction in another.