The phrase "added fluoride" means that fluoride, a substance that helps prevent tooth decay, has been included or put into something as an extra ingredient. Full definition
Breast milk provides all the vitamins and minerals your baby needs, except for vitamin D and possibly fluoride if your local water supply does not add fluoride to drinking water. (aboutkidshealth.ca)
The specially trained staff also add fluoride treatments to improve health and reduce sensitivity. (birdneckanimalhospital.com)
But you do need to make sure that your water does not contain added fluoride, because before 6 months of age, fluoride can actually harm your baby's developing teeth. (pregnancymagazine.com)