Can teething necklaces be worn during sleep?
Because infants and children move around during that period of time, you should remove the necklace whenever your child is without supervision. I recommend putting the necklace around your babies’ ankle with a sock over it to prevent it from coming off during the night.
Ifo from http://www.latvianamberstore.com/publ/baltic_amber_teething_necklace_faq/can_teething_necklaces_be_worn_during_sleep/4-1-0-53