My ds started fussing at 3mo old and it took three weeks for the first two littlw suckers to appear. He got sick with bronchiolitis right after, although he had started to settle again. My hv was really surprised his teeth arrived so early, she says it's usually between 6-8 moths that they appear ,although the grizzling can start far earlier than that.
I took him to the dentist yesterday (never too young to start I guess) and he says he could feel the top two front ones and a canine tooth on the bottom row which he says will really hurt to come through - the eye teeth and molars are the worst....oh joy!!!!!
I give him bonjela on his gums and infant paracetamol to help with th pain - the eye tooth is really hurting him at the moment.