SYNOPSIS
The safety of fluoride use to prevent dental caries has been controversial. To clarify the risk of embryotoxicity of fluoride influencing human fetuses/newborns, we investigated the embryotoxicity levels of 4 fluorides (NaF, KF, SnF2, and CuF2) using the EST method, which is an in vitro embryotoxicity screening test devel-oped by Spielmann et al. in 1997. Of the fluorides, NaF and SnF2 are used to prevent dental caries in Japan. All substances were "non-embryotoxic", but SnF2 and CuF2 were close to the borderline of "weak embryotoxic". Since many young people use fluoride to prevent dental caries, further investigation of the em-bryotoxicity of fluorine is desired.
Key words: embryotoxicity, fluoride, NaF, SnF2, cell differentiation