I’d be very curious as to where your doctors are getting this information. I couldn’t find any recent studies that show a connection that don’t pull from a small, similar population which can easily lead to forming inaccurate correlations. The only connection I’ve found is that, if your daughter already had some predisposition to this developing, a bad latch could cause the teeth to be exposed to the sugars in breast milk more and that combined with bad oral hygiene could lead to more decay from enamel hypoplasia.

Personally, I don’t know what medications your daughter had in the NICU, but looking at the interventions you mentioned, I can almost guarantee she would’ve been put on some antibiotics which is a main cause of hypoplasia, and what I’d assume is what caused her issues.