My first thought was the iron supplements, or even iron in chewable
vitamins.  But if your kids don't take any of these, there are still
plenty of different types of chromogenic bacteria commonly found in
plaque that can cause colored stains (remember the cowpoke with green
teeth?).

Steve

I have had two childre, siblings of ages 4 and 7, that have presented with
black extrinsic line stains on their teeth at the gum line. The children
have great oral hygiene as to other indicators. Otherwise there was no other
finding.. caries free, no plaque/calculus, etc. These stains were easily
cleaned with simple prophy paste.

As I am aware, these stains are harmless and do not increase caries
occurance. Does any have any suggestions to the source of this stain?

Sources that I can think of:

- Iron supplements (they do not take any)

- Tea, Coffee, Tobacco (not present in this case)

- Chlorhexidine (do not take)

Any other possible comon sources?

Thanks in advance