only one of my extended nursers had any kind of tooth decay-and that was riehle...of course all the dentists we saw blamed night nursing as well...i did what i knew was best and continued nursing him as he needed-day or night.
we had some work done, in office, but if i ever had to make the choice again, we'd have the child put under.
fwiw-all the work fell out and had to be redone twice...eventually we had the teeth pulled out completely and now he's got adult teeth in their place and they're healthy, thank the goddess
lll has some good info on night nursing on their site-dentists are idiots when it comes to nursing & teeth.