I’ve recently noticed that my son has greyish streaks on his teeth, the rest of the tooth is white. It starts from the gums and goes down. All 8 of his teeth have this, even the two newest teeth that have barely come through the gums. Not sure what to do. I’ve read it could be too much iron but it says that it should wipe off and it does not. It almost looks like it’s inside the tooth. He has not had any trauma to his teeth or mouth at all. Couldn’t get a picture because he’s such a busy body. Any ideas?