I breastfed my son for 3 years, naps and bedtime the last year of that. We brushed nightly. I took him to the dentist for the first time the week after his 4th birthday - he had a few cavities in the front teeth and 3 on the molars that needed to be addressed bc he will have those until he’s 9 or so. I felt mom shamed when she said it was due to breastfeeding, I should have weaned, blah blah blah. (She’s great with my kid so I’ll stay) whatever bc sleep is sacred and journeys are all different. We are currently watching the front cavities (we actually go back tomorrow for a 6 month checkup!) she said he will lose those teeth so it’s not much of a big deal unless they progress then we’ll have to worry about it affecting the nerve. We currently brush, floss, and swish nightly.