you should be brushing his teeth either with a flannel or baby toothbrush at least twice a day regardless of what he eats or drinks.

I was also told by my MCHN that BM could cause tooth decay because of all the natural sweetness but I figured its better for her to have the BF rather than fruit etc as the natural acidity in fruits can contribute to tooth decay. We started giving DD a sip of water AFTER her BF through the nights if she hadn't fallen asleep, to help wash away some of the BM may try this as well??