Yes. Nursing caries. Can occur from repeated exposure of the lingual, or tongue, side of the. The teeth to the sugar in breast milk, especially if the mother & baby have streptococcus mutans bacteria in their mouths. When mom & baby fall asleep, the nipple retracts, allowing breast milk to bathe the baby's emerging teeth repeatedly. At 6 months, night feeds become a habit. See healthy children. Org for safe sleep.
Unlikely. Unlike bottles, most mothers do disengage once the baby is asleep. Of course, a degree of caries is possible even with breast feeding.