R.R.
Hi M.,
Completely safe to nurse them to sleep, no need to brush their teeth first. Your breastmilk will not pool in your son's mouth like milk from a bottle.
I will share my experiences with you- I have two children, 3.5 & 13 mos. I nursed my oldest to sleep his first 18 months, then gradually transitioned him to sleep on his own- by 2 years he would lay in his bed, stay there, and fall asleep on his own after we had a story and said prayers. I "gradually transitioned" by going to his room when he woke up wishing to nurse, and rocking him for a bit, then setting him back in bed. If he got upset, I'd do it again, and so on and so forth- sometimes laying him down on his tummy (not as an infant of course) and holding his shoulders firmly with one hand and patting him with the other hand gently helped too.
My second son is a nurse-a-holic, but even he will go to bed without nursing if it is his bedtime and he nursed recently and doesn't need more in the tank at the moment. I've also taught him that when mommy is done letting him nurse, mommy is done- so if I am tired of being in the same position or just tired of having my boob sucked on- we cuddle or rock and he falls asleep.
I read the Ezzo's book 'Baby Wise' and I can understand why people may think your baby will never learn to fall asleep on their own if you nurse them/rock them etc. But, my first DID, and he is a strong willed child, not an "easy baby". So, I tend to be drawn to the camp that says if you give them what they need (and of course, only if you are willing and not doing it for reasons that leave you feeling bitter or sleep deprived), when they're ready they'll be happy to do it for themselves.
Sounds like you're a very conscientious mom and I'd recommend the book "Heaven on Earth" for a great read on harmonious parenting of little ones! It talks a lot about "rhythms" that will help your baby be ready for what comes next and be conditioned to not only accept, but look forward to each part of the day, whether it's napping or going to bed for the night. Also, "The Quotidian Mysteries: Laundry, Liturgy, & Women's Work" is a short but philosophical and enriching book that really helped me get so much spiritual meaning out of the dishes and laundry which "are consuming your waking life" =) I also add that, as you said, "Many right things CONFLICT"- how true! One of the wonderful things about mothering is that if we let it, it will bring out intuition to guide us in caring for our children in a way that affirms US and affirms THEM- even if it wouldn't work for someone else. So, maybe nursing children to sleep isn't right for others, but might be right for you.