This is a question that most mothers ask, but they should know that iron drops do not cause caries, but they can distinguish teeth that have eroded or begun to decay due to disruption of the enamel layer by blackening them.
Mothers should be careful after giving iron drops to a child, for example, 4 teeth will turn black and the rest will remain white, so if the cause of blackening of the teeth is iron drops, all teeth should turn black, not the few decayed teeth.
One of the common types of caries in the upper front teeth is the caries of breastfeeding either from breast milk or pasteurized milk, especially at night.