My son needs iron supplements, how can i prevent these from rotting his teeth?

Don't worry : The supplements will not rot out his teeth. Just work on his oral hygiene (brush and floss at least twice daily) and eat and drink a healthy diet. His teeth and gums will be fine. Good luck.

They won't: But bacteria will. Start with a professional cleaning @ Dentist's office. Ask Dentist for proper oral hygiene instructions and diet review. Regular professional care is mandatory.