fluoride has been used to prevent dental caries. it is used in supply water and toothpastes. one undesirable effect has been found: mild dental fluorosis. such stains have aroused concern among specialists. this paper examines, in the literature, ethical aspects resulting from the use of fluoride in public health associated with the "caries prevention versus mild fluorosis occurrence" contradiction and investigates the occurrence of any ethical dilemma among the professionals involved in decision on the use of such products. databases were assessed to identify papers through terms such as ética, bioética, ethics and fluor. the material contributed to the drawing up of a questionnaire answered by researchers and health authorities. the data provided by the interviews underwent content analysis. the ethics dilemma may be stated as: "the use of fluoride products to prevent dental caries has in public health the inconvenience of producing mild dental fluorosis in the population, however, the non-use of fluoride has the inconvenience of not preventing the appearance of a disease (caries) that can be prevented if such product is used." the dilemma has shown to be solved, by admitting that the use of such products would be fair and that its benefit would exceed its damages. nevertheless, some of the respondents admitted a violation of the principle of autonomy.