I nurse my daughter to sleep at night. Will I give her cavities?

My daughter likes the comfort of feeding before bed. She likes to fall asleep nursing, like a pacifier. She refuses bottles and pacifiers. Will I eventually give her cavities? She is only five months old. God gave me the ability to comfort her and feed her, I don't want to take that away from her. I will not ever use formula as it is not what was intended for her. I am worried about the cavity issue. I would hate to give them to her. I will endure being bitten. That is no problem, it will only be temporary until she figures out how to nurse without biting.