My 6 year old daughter has brown stains on her teeth, what should i do to make her teeth white again?

Microabrasion!: A minimally invasive dental procedure called microabrasion uses a slurry of flour of pumice and a mild solution of hydrochloric acid to gently and painlessly remove the brown/gray stains of dental fluorosis. If your stains are white, then you can augment the effect with dental whitening afterward. Other stain causes should be evaluated by your dentist.

See dentist: If they are stains, your dentist can clean them off and instruct you and your child in correct oral hygiene. If they are cavities, they need treatment. This is not a diy problem, call the pro.