Moreover, as a handy treatment, some teeth were blackened by painting with a powder mixture of fushiko (gallnut powder), iron sulfate, and oyster shell, however, this method was not so popular.
又、簡便にした処方として、五倍子粉、硫酸鉄、蠣殻を合わせた粉末を歯に塗るだけのものもあったが、あまり普及しなかった。