Fluorosis
Fluorosis is a condition in which your body has been exposed to too much fluoride. In normal doses (typically found in a safe drinking water system and an ADA-approved toothpaste), fluoride is a healthy compound that promotes strong teeth, which has the ability to fight cavities and other problems.

But sometimes, fluorosis occurs when fluoride-containing toothpastes or rinses are swallowed, instead of expelled.

Fluorosis causes a number of aesthetic problems, including abnormally darkened or stained teeth. While such problems are generally harmless to your health, they can create concerns with your appearance.