The fluoride mixes with enamel, the hard surface on teeth, to help prevent holes, or cavities,from forming.

VOA: special.2009.03.11

They click upon themselves as the breeze rises and turn many-colored as the stir cracks and crazes their enamel.

一阵风吹起，树枝就咯喇喇响,闪射出五彩缤纷，原来这一颤动,冰块坼裂成瓷瓶上的无数细纹。

耶鲁公开课 - 现代诗歌课程节选

Researchers tested new household enamel paints from twelve countries in Africa, Asia and South America.

VOA: special.2009.08.31

It found that the majority of new enamel paints from China, India and Malaysia contained lead at levels of at least five thousand parts per million.

VOA: special.2009.08.31