I believe this just happens in some children.  There is newer evidence that when our mouths become colonized with bacteria, as they all do, there are different types of bacteria.  Some are more aggressive and some are "nice".  This is why it dental cavaties are thought to run in families.  Mom licks the spoon and then feeds baby and baby is given the same bacteria-aggressive or friendly.  I have two close friends with young daughters whose teeth are all the sudden horrible.  Like capped teeth, pulled teeth, crowned teeth, many cavaties.  They do not have CAH and they brush regularly and eat healthy.  You just never know.  Julia