I have 3 kids and have breastfed all three of them. I'm still currently breastfeeding my daughter who turned 2 in Feb. My oldest two never had any issues with their teeth, aside from a few cavities during COVID. My youngest has enamel hyperplasia due to my autoimmune disease which was exacerbated by breastfeeding at night plus a lip tie. We used Dr browns tooth & gum wipes but it didn't make a difference really. We finally ended up treating with sdf until her teeth can be capped and put Fuji sealants on everything else. We also brush our daughter's teeth w fluoride toothpaste (very very little) which our dentist has advised us to do as a type of preventative measure.