teeth, stained

Children's teeth may become discolored for a number of reasons. Certain substances can actually discolor the enamel:

Floride in excessive amounts can cause fluorosis, which can vary in severity from minor white patches to brown stains
Hyperbilirubinemia in the newborn period can cause dark staining of the deciduous teeth ("baby teeth")
Tetracycline antibiotics given to the mother after the third month of gestation or to the child before age 8 can cause brown or yellow discoloration of the enamel; very short courses of tetracycline, for example for suspected Rocky Mountain fever after a tick bite, do not seem to carry as much risk of staining as longer or repeated courses
Iron drops given for iron deficiency may seem to stain the teeth, but actually only stain the accumulated plaque, not the enamel itself; these black stains eventually are removed by brushing. The discoloration of iron drops can be minimized by mixing the iron drops in some apple juice and giving them with a straw or sippee cup.