Well, when you have a root canal there is always an infection left-they can't get it all, it's impossible. There are millions of microscopic canals they simply cannot get into to, but the bacteria is still in them.

I'm sure you'll get a better answer later that can explain the inflammation/antibiotics, because I don't know the answer.

I can say, I've had a front tooth removed and had a "flipper' while my implants healed, I got it the same day as my extraction. Dentists/surgeons can work together to make sure you are not without a front tooth!